CINXE.COM

<!DOCTYPE html> <html class="client-nojs vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-sticky-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-enabled skin-theme-clientpref-day vector-toc-available" lang="en" dir="ltr"> <head> <meta charset="UTF-8"> <title>Cooperation (evolution) - Wikipedia</title> <script>(function(){var className="client-js vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-sticky-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-enabled skin-theme-clientpref-day vector-toc-available";var cookie=document.cookie.match(/(?:^|; )enwikimwclientpreferences=([^;]+)/);if(cookie){cookie[1].split('%2C').forEach(function(pref){className=className.replace(new RegExp('(^| )'+pref.replace(/-clientpref-\w+$|[^\w-]+/g,'')+'-clientpref-\\w+( |$)'),'$1'+pref+'$2');});}document.documentElement.className=className;}());RLCONF={"wgBreakFrames":false,"wgSeparatorTransformTable":["",""],"wgDigitTransformTable":["",""],"wgDefaultDateFormat":"dmy", "wgMonthNames":["","January","February","March","April","May","June","July","August","September","October","November","December"],"wgRequestId":"08562f7f-29c7-41bd-a48c-faaeb352315d","wgCanonicalNamespace":"","wgCanonicalSpecialPageName":false,"wgNamespaceNumber":0,"wgPageName":"Cooperation_(evolution)","wgTitle":"Cooperation (evolution)","wgCurRevisionId":1258135617,"wgRevisionId":1258135617,"wgArticleId":4839105,"wgIsArticle":true,"wgIsRedirect":false,"wgAction":"view","wgUserName":null,"wgUserGroups":["*"],"wgCategories":["CS1 errors: periodical ignored","CS1 errors: missing periodical","Articles with short description","Short description matches Wikidata","Use dmy dates from January 2021","Evolutionary biology","Ethology"],"wgPageViewLanguage":"en","wgPageContentLanguage":"en","wgPageContentModel":"wikitext","wgRelevantPageName":"Cooperation_(evolution)","wgRelevantArticleId":4839105,"wgIsProbablyEditable":true,"wgRelevantPageIsProbablyEditable":true,"wgRestrictionEdit":[], "wgRestrictionMove":[],"wgNoticeProject":"wikipedia","wgCiteReferencePreviewsActive":false,"wgFlaggedRevsParams":{"tags":{"status":{"levels":1}}},"wgMediaViewerOnClick":true,"wgMediaViewerEnabledByDefault":true,"wgPopupsFlags":0,"wgVisualEditor":{"pageLanguageCode":"en","pageLanguageDir":"ltr","pageVariantFallbacks":"en"},"wgMFDisplayWikibaseDescriptions":{"search":true,"watchlist":true,"tagline":false,"nearby":true},"wgWMESchemaEditAttemptStepOversample":false,"wgWMEPageLength":50000,"wgRelatedArticlesCompat":[],"wgCentralAuthMobileDomain":false,"wgEditSubmitButtonLabelPublish":true,"wgULSPosition":"interlanguage","wgULSisCompactLinksEnabled":false,"wgVector2022LanguageInHeader":true,"wgULSisLanguageSelectorEmpty":false,"wgWikibaseItemId":"Q3312519","wgCheckUserClientHintsHeadersJsApi":["brands","architecture","bitness","fullVersionList","mobile","model","platform","platformVersion"],"GEHomepageSuggestedEditsEnableTopics":true,"wgGETopicsMatchModeEnabled":false, "wgGEStructuredTaskRejectionReasonTextInputEnabled":false,"wgGELevelingUpEnabledForUser":false};RLSTATE={"ext.globalCssJs.user.styles":"ready","site.styles":"ready","user.styles":"ready","ext.globalCssJs.user":"ready","user":"ready","user.options":"loading","ext.cite.styles":"ready","skins.vector.search.codex.styles":"ready","skins.vector.styles":"ready","skins.vector.icons":"ready","jquery.makeCollapsible.styles":"ready","ext.wikimediamessages.styles":"ready","ext.visualEditor.desktopArticleTarget.noscript":"ready","ext.uls.interlanguage":"ready","wikibase.client.init":"ready","ext.wikimediaBadges":"ready"};RLPAGEMODULES=["ext.cite.ux-enhancements","mediawiki.page.media","ext.scribunto.logs","site","mediawiki.page.ready","jquery.makeCollapsible","mediawiki.toc","skins.vector.js","ext.centralNotice.geoIP","ext.centralNotice.startUp","ext.gadget.ReferenceTooltips","ext.gadget.switcher","ext.urlShortener.toolbar","ext.centralauth.centralautologin","mmv.bootstrap","ext.popups", "ext.visualEditor.desktopArticleTarget.init","ext.visualEditor.targetLoader","ext.echo.centralauth","ext.eventLogging","ext.wikimediaEvents","ext.navigationTiming","ext.uls.interface","ext.cx.eventlogging.campaigns","ext.cx.uls.quick.actions","wikibase.client.vector-2022","ext.checkUser.clientHints","ext.growthExperiments.SuggestedEditSession","wikibase.sidebar.tracking"];</script> <script>(RLQ=window.RLQ||[]).push(function(){mw.loader.impl(function(){return["user.options@12s5i",function($,jQuery,require,module){mw.user.tokens.set({"patrolToken":"+\\","watchToken":"+\\","csrfToken":"+\\"}); }];});});</script> <link rel="stylesheet" href="/w/load.php?lang=en&modules=ext.cite.styles%7Cext.uls.interlanguage%7Cext.visualEditor.desktopArticleTarget.noscript%7Cext.wikimediaBadges%7Cext.wikimediamessages.styles%7Cjquery.makeCollapsible.styles%7Cskins.vector.icons%2Cstyles%7Cskins.vector.search.codex.styles%7Cwikibase.client.init&only=styles&skin=vector-2022"> <script async="" src="/w/load.php?lang=en&modules=startup&only=scripts&raw=1&skin=vector-2022"></script> <meta name="ResourceLoaderDynamicStyles" content=""> <link rel="stylesheet" href="/w/load.php?lang=en&modules=site.styles&only=styles&skin=vector-2022"> <meta name="generator" content="MediaWiki 1.44.0-wmf.4"> <meta name="referrer" content="origin"> <meta name="referrer" content="origin-when-cross-origin"> <meta name="robots" content="max-image-preview:standard"> <meta name="format-detection" content="telephone=no"> <meta name="viewport" content="width=1120"> <meta property="og:title" content="Cooperation (evolution) - Wikipedia"> <meta property="og:type" content="website"> <link rel="preconnect" href="//upload.wikimedia.org"> <link rel="alternate" media="only screen and (max-width: 640px)" href="//en.m.wikipedia.org/wiki/Cooperation_(evolution)"> <link rel="alternate" type="application/x-wiki" title="Edit this page" href="/w/index.php?title=Cooperation_(evolution)&action=edit"> <link rel="apple-touch-icon" href="/static/apple-touch/wikipedia.png"> <link rel="icon" href="/static/favicon/wikipedia.ico"> <link rel="search" type="application/opensearchdescription+xml" href="/w/rest.php/v1/search" title="Wikipedia (en)"> <link rel="EditURI" type="application/rsd+xml" href="//en.wikipedia.org/w/api.php?action=rsd"> <link rel="canonical" href="https://en.wikipedia.org/wiki/Cooperation_(evolution)"> <link rel="license" href="https://creativecommons.org/licenses/by-sa/4.0/deed.en"> <link rel="alternate" type="application/atom+xml" title="Wikipedia Atom feed" href="/w/index.php?title=Special:RecentChanges&feed=atom"> <link rel="dns-prefetch" href="//meta.wikimedia.org" /> <link rel="dns-prefetch" href="//login.wikimedia.org"> </head> <body class="skin--responsive skin-vector skin-vector-search-vue mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject mw-editable page-Cooperation_evolution rootpage-Cooperation_evolution skin-vector-2022 action-view"><a class="mw-jump-link" href="#bodyContent">Jump to content</a> <div class="vector-header-container"> <header class="vector-header mw-header"> <div class="vector-header-start"> <nav class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-dropdown" class="vector-dropdown vector-main-menu-dropdown vector-button-flush-left vector-button-flush-right" > <input type="checkbox" id="vector-main-menu-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-main-menu-dropdown" class="vector-dropdown-checkbox " aria-label="Main menu" > <label id="vector-main-menu-dropdown-label" for="vector-main-menu-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-menu mw-ui-icon-wikimedia-menu"></span> <span class="vector-dropdown-label-text">Main menu</span> </label> <div class="vector-dropdown-content"> <div id="vector-main-menu-unpinned-container" class="vector-unpinned-container"> <div id="vector-main-menu" class="vector-main-menu vector-pinnable-element"> <div class="vector-pinnable-header vector-main-menu-pinnable-header vector-pinnable-header-unpinned" data-feature-name="main-menu-pinned" data-pinnable-element-id="vector-main-menu" data-pinned-container-id="vector-main-menu-pinned-container" data-unpinned-container-id="vector-main-menu-unpinned-container" > <div class="vector-pinnable-header-label">Main menu</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-main-menu.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-main-menu.unpin">hide</button> </div> <div id="p-navigation" class="vector-menu mw-portlet mw-portlet-navigation" > <div class="vector-menu-heading"> Navigation </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-mainpage-description" class="mw-list-item"><a href="/wiki/Main_Page" title="Visit the main page [z]" accesskey="z"><span>Main page</span></a></li><li id="n-contents" class="mw-list-item"><a href="/wiki/Wikipedia:Contents" title="Guides to browsing Wikipedia"><span>Contents</span></a></li><li id="n-currentevents" class="mw-list-item"><a href="/wiki/Portal:Current_events" title="Articles related to current events"><span>Current events</span></a></li><li id="n-randompage" class="mw-list-item"><a href="/wiki/Special:Random" title="Visit a randomly selected article [x]" accesskey="x"><span>Random article</span></a></li><li id="n-aboutsite" class="mw-list-item"><a href="/wiki/Wikipedia:About" title="Learn about Wikipedia and how it works"><span>About Wikipedia</span></a></li><li id="n-contactpage" class="mw-list-item"><a href="//en.wikipedia.org/wiki/Wikipedia:Contact_us" title="How to contact Wikipedia"><span>Contact us</span></a></li> </ul> </div> </div> <div id="p-interaction" class="vector-menu mw-portlet mw-portlet-interaction" > <div class="vector-menu-heading"> Contribute </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-help" class="mw-list-item"><a href="/wiki/Help:Contents" title="Guidance on how to use and edit Wikipedia"><span>Help</span></a></li><li id="n-introduction" class="mw-list-item"><a href="/wiki/Help:Introduction" title="Learn how to edit Wikipedia"><span>Learn to edit</span></a></li><li id="n-portal" class="mw-list-item"><a href="/wiki/Wikipedia:Community_portal" title="The hub for editors"><span>Community portal</span></a></li><li id="n-recentchanges" class="mw-list-item"><a href="/wiki/Special:RecentChanges" title="A list of recent changes to Wikipedia [r]" accesskey="r"><span>Recent changes</span></a></li><li id="n-upload" class="mw-list-item"><a href="/wiki/Wikipedia:File_upload_wizard" title="Add images or other media for use on Wikipedia"><span>Upload file</span></a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> <a href="/wiki/Main_Page" class="mw-logo"> <img class="mw-logo-icon" src="/static/images/icons/wikipedia.png" alt="" aria-hidden="true" height="50" width="50"> <span class="mw-logo-container skin-invert"> <img class="mw-logo-wordmark" alt="Wikipedia" src="/static/images/mobile/copyright/wikipedia-wordmark-en.svg" style="width: 7.5em; height: 1.125em;"> <img class="mw-logo-tagline" alt="The Free Encyclopedia" src="/static/images/mobile/copyright/wikipedia-tagline-en.svg" width="117" height="13" style="width: 7.3125em; height: 0.8125em;"> </span> </a> </div> <div class="vector-header-end"> <div id="p-search" role="search" class="vector-search-box-vue vector-search-box-collapses vector-search-box-show-thumbnail vector-search-box-auto-expand-width vector-search-box"> <a href="/wiki/Special:Search" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only search-toggle" title="Search Wikipedia [f]" accesskey="f"><span class="vector-icon mw-ui-icon-search mw-ui-icon-wikimedia-search"></span> <span>Search</span> </a> <div class="vector-typeahead-search-container"> <div class="cdx-typeahead-search cdx-typeahead-search--show-thumbnail cdx-typeahead-search--auto-expand-width"> <form action="/w/index.php" id="searchform" class="cdx-search-input cdx-search-input--has-end-button"> <div id="simpleSearch" class="cdx-search-input__input-wrapper" data-search-loc="header-moved"> <div class="cdx-text-input cdx-text-input--has-start-icon"> <input class="cdx-text-input__input" type="search" name="search" placeholder="Search Wikipedia" aria-label="Search Wikipedia" autocapitalize="sentences" title="Search Wikipedia [f]" accesskey="f" id="searchInput" > <span class="cdx-text-input__icon cdx-text-input__start-icon"></span> </div> <input type="hidden" name="title" value="Special:Search"> </div> <button class="cdx-button cdx-search-input__end-button">Search</button> </form> </div> </div> </div> <nav class="vector-user-links vector-user-links-wide" aria-label="Personal tools"> <div class="vector-user-links-main"> <div id="p-vector-user-menu-preferences" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-userpage" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <nav class="vector-appearance-landmark" aria-label="Appearance"> <div id="vector-appearance-dropdown" class="vector-dropdown " title="Change the appearance of the page's font size, width, and color" > <input type="checkbox" id="vector-appearance-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-appearance-dropdown" class="vector-dropdown-checkbox " aria-label="Appearance" > <label id="vector-appearance-dropdown-label" for="vector-appearance-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-appearance mw-ui-icon-wikimedia-appearance"></span> <span class="vector-dropdown-label-text">Appearance</span> </label> <div class="vector-dropdown-content"> <div id="vector-appearance-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <div id="p-vector-user-menu-notifications" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-overflow" class="vector-menu mw-portlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="https://donate.wikimedia.org/wiki/Special:FundraiserRedirector?utm_source=donate&utm_medium=sidebar&utm_campaign=C13_en.wikipedia.org&uselang=en" class=""><span>Donate</span></a> </li> <li id="pt-createaccount-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:CreateAccount&returnto=Cooperation+%28evolution%29" title="You are encouraged to create an account and log in; however, it is not mandatory" class=""><span>Create account</span></a> </li> <li id="pt-login-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:UserLogin&returnto=Cooperation+%28evolution%29" title="You're encouraged to log in; however, it's not mandatory. [o]" accesskey="o" class=""><span>Log in</span></a> </li> </ul> </div> </div> </div> <div id="vector-user-links-dropdown" class="vector-dropdown vector-user-menu vector-button-flush-right vector-user-menu-logged-out" title="Log in and more options" > <input type="checkbox" id="vector-user-links-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-user-links-dropdown" class="vector-dropdown-checkbox " aria-label="Personal tools" > <label id="vector-user-links-dropdown-label" for="vector-user-links-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-ellipsis mw-ui-icon-wikimedia-ellipsis"></span> <span class="vector-dropdown-label-text">Personal tools</span> </label> <div class="vector-dropdown-content"> <div id="p-personal" class="vector-menu mw-portlet mw-portlet-personal user-links-collapsible-item" title="User menu" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport" class="user-links-collapsible-item mw-list-item"><a href="https://donate.wikimedia.org/wiki/Special:FundraiserRedirector?utm_source=donate&utm_medium=sidebar&utm_campaign=C13_en.wikipedia.org&uselang=en"><span>Donate</span></a></li><li id="pt-createaccount" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:CreateAccount&returnto=Cooperation+%28evolution%29" title="You are encouraged to create an account and log in; however, it is not mandatory"><span class="vector-icon mw-ui-icon-userAdd mw-ui-icon-wikimedia-userAdd"></span> <span>Create account</span></a></li><li id="pt-login" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:UserLogin&returnto=Cooperation+%28evolution%29" title="You're encouraged to log in; however, it's not mandatory. [o]" accesskey="o"><span class="vector-icon mw-ui-icon-logIn mw-ui-icon-wikimedia-logIn"></span> <span>Log in</span></a></li> </ul> </div> </div> <div id="p-user-menu-anon-editor" class="vector-menu mw-portlet mw-portlet-user-menu-anon-editor" > <div class="vector-menu-heading"> Pages for logged out editors <a href="/wiki/Help:Introduction" aria-label="Learn more about editing"><span>learn more</span></a> </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-anoncontribs" class="mw-list-item"><a href="/wiki/Special:MyContributions" title="A list of edits made from this IP address [y]" accesskey="y"><span>Contributions</span></a></li><li id="pt-anontalk" class="mw-list-item"><a href="/wiki/Special:MyTalk" title="Discussion about edits from this IP address [n]" accesskey="n"><span>Talk</span></a></li> </ul> </div> </div> </div> </div> </nav> </div> </header> </div> <div class="mw-page-container"> <div class="mw-page-container-inner"> <div class="vector-sitenotice-container"> <div id="siteNotice"></div> </div> <div class="vector-column-start"> <div class="vector-main-menu-container"> <div id="mw-navigation"> <nav id="mw-panel" class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-pinned-container" class="vector-pinned-container"> </div> </nav> </div> </div> <div class="vector-sticky-pinned-container"> <nav id="mw-panel-toc" aria-label="Contents" data-event-name="ui.sidebar-toc" class="mw-table-of-contents-container vector-toc-landmark"> <div id="vector-toc-pinned-container" class="vector-pinned-container"> <div id="vector-toc" class="vector-toc vector-pinnable-element"> <div class="vector-pinnable-header vector-toc-pinnable-header vector-pinnable-header-pinned" data-feature-name="toc-pinned" data-pinnable-element-id="vector-toc" > <h2 class="vector-pinnable-header-label">Contents</h2> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-toc.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-toc.unpin">hide</button> </div> <ul class="vector-toc-contents" id="mw-panel-toc-list"> <li id="toc-mw-content-text" class="vector-toc-list-item vector-toc-level-1"> <a href="#" class="vector-toc-link"> <div class="vector-toc-text">(Top)</div> </a> </li> <li id="toc-In_animals" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#In_animals"> <div class="vector-toc-text"> <span class="vector-toc-numb">1</span> <span>In animals</span> </div> </a> <button aria-controls="toc-In_animals-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle In animals subsection</span> </button> <ul id="toc-In_animals-sublist" class="vector-toc-list"> <li id="toc-Kin_selection" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Kin_selection"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.1</span> <span>Kin selection</span> </div> </a> <ul id="toc-Kin_selection-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-In_plants" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#In_plants"> <div class="vector-toc-text"> <span class="vector-toc-numb">2</span> <span>In plants</span> </div> </a> <ul id="toc-In_plants-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Explanation" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Explanation"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Explanation</span> </div> </a> <button aria-controls="toc-Explanation-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Explanation subsection</span> </button> <ul id="toc-Explanation-sublist" class="vector-toc-list"> <li id="toc-Direct_fitness_benefits" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Direct_fitness_benefits"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.1</span> <span>Direct fitness benefits</span> </div> </a> <ul id="toc-Direct_fitness_benefits-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Indirect_fitness_benefits" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Indirect_fitness_benefits"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.2</span> <span>Indirect fitness benefits</span> </div> </a> <ul id="toc-Indirect_fitness_benefits-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Multi-level_selection" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Multi-level_selection"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Multi-level selection</span> </div> </a> <ul id="toc-Multi-level_selection-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Market_effect" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Market_effect"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>Market effect</span> </div> </a> <ul id="toc-Market_effect-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Symbiosis" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Symbiosis"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>Symbiosis</span> </div> </a> <button aria-controls="toc-Symbiosis-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Symbiosis subsection</span> </button> <ul id="toc-Symbiosis-sublist" class="vector-toc-list"> <li id="toc-Mutualism" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Mutualism"> <div class="vector-toc-text"> <span class="vector-toc-numb">6.1</span> <span>Mutualism</span> </div> </a> <ul id="toc-Mutualism-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Hidden_benefits" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Hidden_benefits"> <div class="vector-toc-text"> <span class="vector-toc-numb">7</span> <span>Hidden benefits</span> </div> </a> <ul id="toc-Hidden_benefits-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Prisoner's_dilemma" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Prisoner's_dilemma"> <div class="vector-toc-text"> <span class="vector-toc-numb">8</span> <span>Prisoner's dilemma</span> </div> </a> <ul id="toc-Prisoner's_dilemma-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Evolutionary_mechanisms_suggesting_that_reciprocity_is_the_result,_not_the_cause,_of_the_evolution_of_cooperation" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Evolutionary_mechanisms_suggesting_that_reciprocity_is_the_result,_not_the_cause,_of_the_evolution_of_cooperation"> <div class="vector-toc-text"> <span class="vector-toc-numb">9</span> <span>Evolutionary mechanisms suggesting that reciprocity is the result, not the cause, of the evolution of cooperation</span> </div> </a> <ul id="toc-Evolutionary_mechanisms_suggesting_that_reciprocity_is_the_result,_not_the_cause,_of_the_evolution_of_cooperation-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-History_of_cooperation_research" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#History_of_cooperation_research"> <div class="vector-toc-text"> <span class="vector-toc-numb">10</span> <span>History of cooperation research</span> </div> </a> <ul id="toc-History_of_cooperation_research-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> <span class="vector-toc-numb">11</span> <span>See also</span> </div> </a> <ul id="toc-See_also-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Notes" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Notes"> <div class="vector-toc-text"> <span class="vector-toc-numb">12</span> <span>Notes</span> </div> </a> <ul id="toc-Notes-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-References" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> <span class="vector-toc-numb">13</span> <span>References</span> </div> </a> <ul id="toc-References-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-listBullet mw-ui-icon-wikimedia-listBullet"></span> <span class="vector-dropdown-label-text">Toggle the table of contents</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-titlebar-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <h1 id="firstHeading" class="firstHeading mw-first-heading"><span class="mw-page-title-main">Cooperation (evolution)</span></h1> <div id="p-lang-btn" class="vector-dropdown mw-portlet mw-portlet-lang" > <input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="vector-dropdown-checkbox mw-interlanguage-selector" aria-label="Go to an article in another language. Available in 11 languages" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-11" aria-hidden="true" ><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">11 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D8%AA%D8%B9%D8%A7%D9%88%D9%86_(%D8%AA%D8%B7%D9%88%D8%B1)" title="تعاون (تطور) – Arabic" lang="ar" hreflang="ar" data-title="تعاون (تطور)" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-bg mw-list-item"><a href="https://bg.wikipedia.org/wiki/%D0%A1%D1%8A%D1%82%D1%80%D1%83%D0%B4%D0%BD%D0%B8%D1%87%D0%B5%D1%81%D1%82%D0%B2%D0%BE_(%D0%B5%D0%B2%D0%BE%D0%BB%D1%8E%D1%86%D0%B8%D1%8F)" title="Сътрудничество (еволюция) – Bulgarian" lang="bg" hreflang="bg" data-title="Сътрудничество (еволюция)" data-language-autonym="Български" data-language-local-name="Bulgarian" class="interlanguage-link-target"><span>Български</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Cooperaci%C3%B3_(evoluci%C3%B3)" title="Cooperació (evolució) – Catalan" lang="ca" hreflang="ca" data-title="Cooperació (evolució)" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Cooperaci%C3%B3n_(evoluci%C3%B3n)" title="Cooperación (evolución) – Spanish" lang="es" hreflang="es" data-title="Cooperación (evolución)" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D9%87%D9%85%DA%A9%D8%A7%D8%B1%DB%8C_(%D9%81%D8%B1%DA%AF%D8%B4%D8%AA)" title="همکاری (فرگشت) – Persian" lang="fa" hreflang="fa" data-title="همکاری (فرگشت)" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-gl mw-list-item"><a href="https://gl.wikipedia.org/wiki/Cooperaci%C3%B3n_(evoluci%C3%B3n)" title="Cooperación (evolución) – Galician" lang="gl" hreflang="gl" data-title="Cooperación (evolución)" data-language-autonym="Galego" data-language-local-name="Galician" class="interlanguage-link-target"><span>Galego</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%ED%98%91%EB%A0%A5_(%EC%A7%84%ED%99%94)" title="협력 (진화) – Korean" lang="ko" hreflang="ko" data-title="협력 (진화)" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-ml mw-list-item"><a href="https://ml.wikipedia.org/wiki/%E0%B4%B8%E0%B4%B9%E0%B4%95%E0%B4%B0%E0%B4%A3%E0%B4%82_(%E0%B4%9C%E0%B5%80%E0%B4%B5%E0%B4%AA%E0%B4%B0%E0%B4%BF%E0%B4%A3%E0%B4%BE%E0%B4%AE%E0%B4%82)" title="സഹകരണം (ജീവപരിണാമം) – Malayalam" lang="ml" hreflang="ml" data-title="സഹകരണം (ജീവപരിണാമം)" data-language-autonym="മലയാളം" data-language-local-name="Malayalam" class="interlanguage-link-target"><span>മലയാളം</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Coopera%C3%A7%C3%A3o_(biologia)" title="Cooperação (biologia) – Portuguese" lang="pt" hreflang="pt" data-title="Cooperação (biologia)" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/Kar%C5%9F%C4%B1l%C4%B1kl%C4%B1_yard%C4%B1mla%C5%9Fma_(evrim)" title="Karşılıklı yardımlaşma (evrim) – Turkish" lang="tr" hreflang="tr" data-title="Karşılıklı yardımlaşma (evrim)" data-language-autonym="Türkçe" data-language-local-name="Turkish" class="interlanguage-link-target"><span>Türkçe</span></a></li><li class="interlanguage-link interwiki-zh-yue mw-list-item"><a href="https://zh-yue.wikipedia.org/wiki/%E5%90%88%E4%BD%9C_(%E9%80%B2%E5%8C%96)" title="合作 (進化) – Cantonese" lang="yue" hreflang="yue" data-title="合作 (進化)" data-language-autonym="粵語" data-language-local-name="Cantonese" class="interlanguage-link-target"><span>粵語</span></a></li> </ul> <div class="after-portlet after-portlet-lang"><span class="wb-langlinks-edit wb-langlinks-link"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q3312519#sitelinks-wikipedia" title="Edit interlanguage links" class="wbc-editpage">Edit links</a></span></div> </div> </div> </div> </header> <div class="vector-page-toolbar"> <div class="vector-page-toolbar-container"> <div id="left-navigation"> <nav aria-label="Namespaces"> <div id="p-associated-pages" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-associated-pages" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-nstab-main" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/Cooperation_(evolution)" title="View the content page [c]" accesskey="c"><span>Article</span></a></li><li id="ca-talk" class="vector-tab-noicon mw-list-item"><a href="/wiki/Talk:Cooperation_(evolution)" rel="discussion" title="Discuss improvements to the content page [t]" accesskey="t"><span>Talk</span></a></li> </ul> </div> </div> <div id="vector-variants-dropdown" class="vector-dropdown emptyPortlet" > <input type="checkbox" id="vector-variants-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-variants-dropdown" class="vector-dropdown-checkbox " aria-label="Change language variant" > <label id="vector-variants-dropdown-label" for="vector-variants-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet" aria-hidden="true" ><span class="vector-dropdown-label-text">English</span> </label> <div class="vector-dropdown-content"> <div id="p-variants" class="vector-menu mw-portlet mw-portlet-variants emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> </div> </div> </nav> </div> <div id="right-navigation" class="vector-collapsible"> <nav aria-label="Views"> <div id="p-views" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-views" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-view" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/Cooperation_(evolution)"><span>Read</span></a></li><li id="ca-edit" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=Cooperation_(evolution)&action=edit" title="Edit this page [e]" accesskey="e"><span>Edit</span></a></li><li id="ca-history" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=Cooperation_(evolution)&action=history" title="Past revisions of this page [h]" accesskey="h"><span>View history</span></a></li> </ul> </div> </div> </nav> <nav class="vector-page-tools-landmark" aria-label="Page tools"> <div id="vector-page-tools-dropdown" class="vector-dropdown vector-page-tools-dropdown" > <input type="checkbox" id="vector-page-tools-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-tools-dropdown" class="vector-dropdown-checkbox " aria-label="Tools" > <label id="vector-page-tools-dropdown-label" for="vector-page-tools-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet" aria-hidden="true" ><span class="vector-dropdown-label-text">Tools</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-tools-unpinned-container" class="vector-unpinned-container"> <div id="vector-page-tools" class="vector-page-tools vector-pinnable-element"> <div class="vector-pinnable-header vector-page-tools-pinnable-header vector-pinnable-header-unpinned" data-feature-name="page-tools-pinned" data-pinnable-element-id="vector-page-tools" data-pinned-container-id="vector-page-tools-pinned-container" data-unpinned-container-id="vector-page-tools-unpinned-container" > <div class="vector-pinnable-header-label">Tools</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-page-tools.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-page-tools.unpin">hide</button> </div> <div id="p-cactions" class="vector-menu mw-portlet mw-portlet-cactions emptyPortlet vector-has-collapsible-items" title="More options" > <div class="vector-menu-heading"> Actions </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-more-view" class="selected vector-more-collapsible-item mw-list-item"><a href="/wiki/Cooperation_(evolution)"><span>Read</span></a></li><li id="ca-more-edit" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=Cooperation_(evolution)&action=edit" title="Edit this page [e]" accesskey="e"><span>Edit</span></a></li><li id="ca-more-history" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=Cooperation_(evolution)&action=history"><span>View history</span></a></li> </ul> </div> </div> <div id="p-tb" class="vector-menu mw-portlet mw-portlet-tb" > <div class="vector-menu-heading"> General </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="t-whatlinkshere" class="mw-list-item"><a href="/wiki/Special:WhatLinksHere/Cooperation_(evolution)" title="List of all English Wikipedia pages containing links to this page [j]" accesskey="j"><span>What links here</span></a></li><li id="t-recentchangeslinked" class="mw-list-item"><a href="/wiki/Special:RecentChangesLinked/Cooperation_(evolution)" rel="nofollow" title="Recent changes in pages linked from this page [k]" accesskey="k"><span>Related changes</span></a></li><li id="t-upload" class="mw-list-item"><a href="/wiki/Wikipedia:File_Upload_Wizard" title="Upload files [u]" accesskey="u"><span>Upload file</span></a></li><li id="t-specialpages" class="mw-list-item"><a href="/wiki/Special:SpecialPages" title="A list of all special pages [q]" accesskey="q"><span>Special pages</span></a></li><li id="t-permalink" class="mw-list-item"><a href="/w/index.php?title=Cooperation_(evolution)&oldid=1258135617" title="Permanent link to this revision of this page"><span>Permanent link</span></a></li><li id="t-info" class="mw-list-item"><a href="/w/index.php?title=Cooperation_(evolution)&action=info" title="More information about this page"><span>Page information</span></a></li><li id="t-cite" class="mw-list-item"><a href="/w/index.php?title=Special:CiteThisPage&page=Cooperation_%28evolution%29&id=1258135617&wpFormIdentifier=titleform" title="Information on how to cite this page"><span>Cite this page</span></a></li><li id="t-urlshortener" class="mw-list-item"><a href="/w/index.php?title=Special:UrlShortener&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FCooperation_%28evolution%29"><span>Get shortened URL</span></a></li><li id="t-urlshortener-qrcode" class="mw-list-item"><a href="/w/index.php?title=Special:QrCode&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FCooperation_%28evolution%29"><span>Download QR code</span></a></li> </ul> </div> </div> <div id="p-coll-print_export" class="vector-menu mw-portlet mw-portlet-coll-print_export" > <div class="vector-menu-heading"> Print/export </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="coll-download-as-rl" class="mw-list-item"><a href="/w/index.php?title=Special:DownloadAsPdf&page=Cooperation_%28evolution%29&action=show-download-screen" title="Download this page as a PDF file"><span>Download as PDF</span></a></li><li id="t-print" class="mw-list-item"><a href="/w/index.php?title=Cooperation_(evolution)&printable=yes" title="Printable version of this page [p]" accesskey="p"><span>Printable version</span></a></li> </ul> </div> </div> <div id="p-wikibase-otherprojects" class="vector-menu mw-portlet mw-portlet-wikibase-otherprojects" > <div class="vector-menu-heading"> In other projects </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="t-wikibase" class="wb-otherproject-link wb-otherproject-wikibase-dataitem mw-list-item"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q3312519" title="Structured data on this page hosted by Wikidata [g]" accesskey="g"><span>Wikidata item</span></a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> </div> </div> </div> <div class="vector-column-end"> <div class="vector-sticky-pinned-container"> <nav class="vector-page-tools-landmark" aria-label="Page tools"> <div id="vector-page-tools-pinned-container" class="vector-pinned-container"> </div> </nav> <nav class="vector-appearance-landmark" aria-label="Appearance"> <div id="vector-appearance-pinned-container" class="vector-pinned-container"> <div id="vector-appearance" class="vector-appearance vector-pinnable-element"> <div class="vector-pinnable-header vector-appearance-pinnable-header vector-pinnable-header-pinned" data-feature-name="appearance-pinned" data-pinnable-element-id="vector-appearance" data-pinned-container-id="vector-appearance-pinned-container" data-unpinned-container-id="vector-appearance-unpinned-container" > <div class="vector-pinnable-header-label">Appearance</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-appearance.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-appearance.unpin">hide</button> </div> </div> </div> </nav> </div> </div> <div id="bodyContent" class="vector-body" aria-labelledby="firstHeading" data-mw-ve-target-container> <div class="vector-body-before-content"> <div class="mw-indicators"> </div> <div id="siteSub" class="noprint">From Wikipedia, the free encyclopedia</div> </div> <div id="contentSub"><div id="mw-content-subtitle"></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Evolutionary process where groups of organisms work or act together for common or mutual benefits</div> <p class="mw-empty-elt"> </p> <style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist li{margin:0;display:inline}.mw-parser-output .hlist.inline,.mw-parser-output .hlist.inline dl,.mw-parser-output .hlist.inline ol,.mw-parser-output .hlist.inline ul,.mw-parser-output .hlist dl dl,.mw-parser-output .hlist dl ol,.mw-parser-output .hlist dl ul,.mw-parser-output .hlist ol dl,.mw-parser-output .hlist ol ol,.mw-parser-output .hlist ol ul,.mw-parser-output .hlist ul dl,.mw-parser-output .hlist ul ol,.mw-parser-output .hlist ul ul{display:inline}.mw-parser-output .hlist .mw-empty-li{display:none}.mw-parser-output .hlist dt::after{content:": "}.mw-parser-output .hlist dd::after,.mw-parser-output .hlist li::after{content:" · ";font-weight:bold}.mw-parser-output .hlist dd:last-child::after,.mw-parser-output .hlist dt:last-child::after,.mw-parser-output .hlist li:last-child::after{content:none}.mw-parser-output .hlist dd dd:first-child::before,.mw-parser-output .hlist dd dt:first-child::before,.mw-parser-output .hlist dd li:first-child::before,.mw-parser-output .hlist dt dd:first-child::before,.mw-parser-output .hlist dt dt:first-child::before,.mw-parser-output .hlist dt li:first-child::before,.mw-parser-output .hlist li dd:first-child::before,.mw-parser-output .hlist li dt:first-child::before,.mw-parser-output .hlist li li:first-child::before{content:" (";font-weight:normal}.mw-parser-output .hlist dd dd:last-child::after,.mw-parser-output .hlist dd dt:last-child::after,.mw-parser-output .hlist dd li:last-child::after,.mw-parser-output .hlist dt dd:last-child::after,.mw-parser-output .hlist dt dt:last-child::after,.mw-parser-output .hlist dt li:last-child::after,.mw-parser-output .hlist li dd:last-child::after,.mw-parser-output .hlist li dt:last-child::after,.mw-parser-output .hlist li li:last-child::after{content:")";font-weight:normal}.mw-parser-output .hlist ol{counter-reset:listitem}.mw-parser-output .hlist ol>li{counter-increment:listitem}.mw-parser-output .hlist ol>li::before{content:" "counter(listitem)"\a0 "}.mw-parser-output .hlist dd ol>li:first-child::before,.mw-parser-output .hlist dt ol>li:first-child::before,.mw-parser-output .hlist li ol>li:first-child::before{content:" ("counter(listitem)"\a0 "}</style><style data-mw-deduplicate="TemplateStyles:r1126788409">.mw-parser-output .plainlist ol,.mw-parser-output .plainlist ul{line-height:inherit;list-style:none;margin:0;padding:0}.mw-parser-output .plainlist ol li,.mw-parser-output .plainlist ul li{margin-bottom:0}</style><style data-mw-deduplicate="TemplateStyles:r1246091330">.mw-parser-output .sidebar{width:22em;float:right;clear:right;margin:0.5em 0 1em 1em;background:var(--background-color-neutral-subtle,#f8f9fa);border:1px solid var(--border-color-base,#a2a9b1);padding:0.2em;text-align:center;line-height:1.4em;font-size:88%;border-collapse:collapse;display:table}body.skin-minerva .mw-parser-output .sidebar{display:table!important;float:right!important;margin:0.5em 0 1em 1em!important}.mw-parser-output .sidebar-subgroup{width:100%;margin:0;border-spacing:0}.mw-parser-output .sidebar-left{float:left;clear:left;margin:0.5em 1em 1em 0}.mw-parser-output .sidebar-none{float:none;clear:both;margin:0.5em 1em 1em 0}.mw-parser-output .sidebar-outer-title{padding:0 0.4em 0.2em;font-size:125%;line-height:1.2em;font-weight:bold}.mw-parser-output .sidebar-top-image{padding:0.4em}.mw-parser-output .sidebar-top-caption,.mw-parser-output .sidebar-pretitle-with-top-image,.mw-parser-output .sidebar-caption{padding:0.2em 0.4em 0;line-height:1.2em}.mw-parser-output .sidebar-pretitle{padding:0.4em 0.4em 0;line-height:1.2em}.mw-parser-output .sidebar-title,.mw-parser-output .sidebar-title-with-pretitle{padding:0.2em 0.8em;font-size:145%;line-height:1.2em}.mw-parser-output .sidebar-title-with-pretitle{padding:0.1em 0.4em}.mw-parser-output .sidebar-image{padding:0.2em 0.4em 0.4em}.mw-parser-output .sidebar-heading{padding:0.1em 0.4em}.mw-parser-output .sidebar-content{padding:0 0.5em 0.4em}.mw-parser-output .sidebar-content-with-subgroup{padding:0.1em 0.4em 0.2em}.mw-parser-output .sidebar-above,.mw-parser-output .sidebar-below{padding:0.3em 0.8em;font-weight:bold}.mw-parser-output .sidebar-collapse .sidebar-above,.mw-parser-output .sidebar-collapse .sidebar-below{border-top:1px solid #aaa;border-bottom:1px solid #aaa}.mw-parser-output .sidebar-navbar{text-align:right;font-size:115%;padding:0 0.4em 0.4em}.mw-parser-output .sidebar-list-title{padding:0 0.4em;text-align:left;font-weight:bold;line-height:1.6em;font-size:105%}.mw-parser-output .sidebar-list-title-c{padding:0 0.4em;text-align:center;margin:0 3.3em}@media(max-width:640px){body.mediawiki .mw-parser-output .sidebar{width:100%!important;clear:both;float:none!important;margin-left:0!important;margin-right:0!important}}body.skin--responsive .mw-parser-output .sidebar a>img{max-width:none!important}@media screen{html.skin-theme-clientpref-night .mw-parser-output .sidebar:not(.notheme) .sidebar-list-title,html.skin-theme-clientpref-night .mw-parser-output .sidebar:not(.notheme) .sidebar-title-with-pretitle{background:transparent!important}html.skin-theme-clientpref-night .mw-parser-output .sidebar:not(.notheme) .sidebar-title-with-pretitle a{color:var(--color-progressive)!important}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .sidebar:not(.notheme) .sidebar-list-title,html.skin-theme-clientpref-os .mw-parser-output .sidebar:not(.notheme) .sidebar-title-with-pretitle{background:transparent!important}html.skin-theme-clientpref-os .mw-parser-output .sidebar:not(.notheme) .sidebar-title-with-pretitle a{color:var(--color-progressive)!important}}@media print{body.ns-0 .mw-parser-output .sidebar{display:none!important}}</style><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><table class="sidebar sidebar-collapse nomobile nowraplinks" style="border:2px solid #90ee90"><tbody><tr><td class="sidebar-pretitle">Part of a series on</td></tr><tr><th class="sidebar-title-with-pretitle" style="background:#90ee90;padding:0.2em;font-size:175%;font-weight:bold"><a href="/wiki/Evolutionary_biology" title="Evolutionary biology">Evolutionary biology</a></th></tr><tr><td class="sidebar-image"><span class="notpageimage" typeof="mw:File"><a href="/wiki/File:Darwin%27s_finches_by_Gould.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/a/ae/Darwin%27s_finches_by_Gould.jpg/180px-Darwin%27s_finches_by_Gould.jpg" decoding="async" width="180" height="136" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/a/ae/Darwin%27s_finches_by_Gould.jpg/270px-Darwin%27s_finches_by_Gould.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/a/ae/Darwin%27s_finches_by_Gould.jpg/360px-Darwin%27s_finches_by_Gould.jpg 2x" data-file-width="1748" data-file-height="1319" /></a></span><div class="sidebar-caption"><a href="/wiki/Darwin%27s_finches" title="Darwin's finches">Darwin's finches</a> by <a href="/wiki/John_Gould" title="John Gould">John Gould</a></div></td></tr><tr><td class="sidebar-above" style="display:block; margin-bottom:0.55em; background-color: transparent;"> <div class="hlist"> <ul><li><a href="/wiki/Index_of_evolutionary_biology_articles" title="Index of evolutionary biology articles">Index</a></li> <li><a href="/wiki/Introduction_to_evolution" title="Introduction to evolution">Introduction</a></li> <li><a href="/wiki/Evolution" title="Evolution">Main</a></li> <li><a href="/wiki/Outline_of_evolution" title="Outline of evolution">Outline</a></li></ul> <div class="hlist"> </div> <ul><li><a href="/wiki/Glossary_of_evolutionary_biology" class="mw-redirect" title="Glossary of evolutionary biology">Glossary</a></li> <li><a href="/wiki/Evidence_of_common_descent" title="Evidence of common descent">Evidence</a></li> <li><a href="/wiki/History_of_life" title="History of life">History</a></li></ul> </div></td></tr><tr><td class="sidebar-content" style="background:transparent;"> <div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="text-align:center;padding-bottom:0;background:#90ee90;font-size:100%;font-weight:bold;;color: var(--color-base)">Processes and outcomes</div><div class="sidebar-list-content mw-collapsible-content plainlist"><div class="hlist"> <ul><li><a href="/wiki/Population_genetics" title="Population genetics">Population genetics</a></li> <li><a href="/wiki/Genetic_variation" title="Genetic variation">Variation</a></li> <li><a href="/wiki/Genetic_diversity" title="Genetic diversity">Diversity</a></li> <li><a href="/wiki/Mutation" title="Mutation">Mutation</a></li> <li><a href="/wiki/Natural_selection" title="Natural selection">Natural selection</a></li> <li><a href="/wiki/Adaptation" title="Adaptation">Adaptation</a></li> <li><a href="/wiki/Polymorphism_(biology)" title="Polymorphism (biology)">Polymorphism</a></li> <li><a href="/wiki/Genetic_drift" title="Genetic drift">Genetic drift</a></li> <li><a href="/wiki/Gene_flow" title="Gene flow">Gene flow</a></li> <li><a href="/wiki/Speciation" title="Speciation">Speciation</a></li> <li><a href="/wiki/Adaptive_radiation" title="Adaptive radiation">Adaptive radiation</a></li> <li><a class="mw-selflink selflink">Co-operation</a></li> <li><a href="/wiki/Coevolution" title="Coevolution">Coevolution</a></li> <li><a href="/wiki/Coextinction" title="Coextinction">Coextinction</a></li> <li><a href="/wiki/Contingency_(evolutionary_biology)" title="Contingency (evolutionary biology)">Contingency</a></li> <li><a href="/wiki/Divergent_evolution" title="Divergent evolution">Divergence</a></li> <li><a href="/wiki/Convergent_evolution" title="Convergent evolution">Convergence</a></li> <li><a href="/wiki/Parallel_evolution" title="Parallel evolution">Parallel evolution</a></li> <li><a href="/wiki/Extinction" title="Extinction">Extinction</a></li></ul> </div></div></div></td> </tr><tr><td class="sidebar-content" style="background:transparent;"> <div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="text-align:center;padding-bottom:0;background:#90ee90;font-size:100%;font-weight:bold;;color: var(--color-base)">Natural history</div><div class="sidebar-list-content mw-collapsible-content plainlist"><div class="hlist"> <ul><li><a href="/wiki/Abiogenesis" title="Abiogenesis">Origin of life</a></li> <li><a href="/wiki/Common_descent" title="Common descent">Common descent</a></li> <li><a href="/wiki/History_of_life" title="History of life">History of life</a></li> <li><a href="/wiki/Timeline_of_the_evolutionary_history_of_life" title="Timeline of the evolutionary history of life">Timeline of evolution</a></li> <li><a href="/wiki/Human_evolution" title="Human evolution">Human evolution</a> <ul><li><a href="/wiki/Recent_human_evolution" title="Recent human evolution">Recent human evolution</a></li></ul></li> <li><a href="/wiki/Phylogenetic_tree" title="Phylogenetic tree">Phylogeny</a></li> <li><a href="/wiki/Biodiversity" title="Biodiversity">Biodiversity</a></li> <li><a href="/wiki/Biogeography" title="Biogeography">Biogeography</a></li> <li><a href="/wiki/Taxonomy_(biology)" title="Taxonomy (biology)">Classification</a></li> <li><a href="/wiki/Evolutionary_taxonomy" title="Evolutionary taxonomy">Evolutionary taxonomy</a></li> <li><a href="/wiki/Cladistics" title="Cladistics">Cladistics</a></li> <li><a href="/wiki/Transitional_fossil" title="Transitional fossil">Transitional fossil</a></li> <li><a href="/wiki/Extinction_event" title="Extinction event">Extinction event</a></li></ul> </div></div></div></td> </tr><tr><td class="sidebar-content" style="background:transparent;"> <div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="text-align:center;padding-bottom:0;background:#90ee90;font-size:100%;font-weight:bold;;color: var(--color-base)">History of evolutionary theory</div><div class="sidebar-list-content mw-collapsible-content plainlist"><div class="hlist"> <ul><li><a href="/wiki/History_of_evolutionary_thought" title="History of evolutionary thought">Overview</a></li> <li><a href="/wiki/Evolutionary_ideas_of_the_Renaissance_and_Enlightenment" title="Evolutionary ideas of the Renaissance and Enlightenment">Renaissance</a></li> <li><a href="/wiki/Transmutation_of_species" title="Transmutation of species">Before Darwin</a></li> <li><a href="/wiki/Charles_Darwin" title="Charles Darwin">Darwin</a></li> <li><i><a href="/wiki/On_the_Origin_of_Species" title="On the Origin of Species">Origin of Species</a></i></li> <li><a href="/wiki/The_eclipse_of_Darwinism" title="The eclipse of Darwinism">Before synthesis</a></li> <li><a href="/wiki/Modern_synthesis_(20th_century)" title="Modern synthesis (20th century)">Modern synthesis</a></li> <li><a href="/wiki/History_of_molecular_evolution" title="History of molecular evolution">Molecular evolution</a></li> <li><a href="/wiki/Evolutionary_developmental_biology" title="Evolutionary developmental biology">Evo-devo</a></li> <li><a href="/wiki/Current_research_in_evolutionary_biology" class="mw-redirect" title="Current research in evolutionary biology">Current research</a></li> <li><a href="/wiki/History_of_speciation" title="History of speciation">History of speciation</a></li> <li><a href="/wiki/History_of_paleontology" title="History of paleontology">History of paleontology</a> (<a href="/wiki/Timeline_of_paleontology" title="Timeline of paleontology">timeline</a>)</li></ul> </div></div></div></td> </tr><tr><td class="sidebar-content" style="background:transparent;"> <div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="text-align:center;padding-bottom:0;background:#90ee90;font-size:100%;font-weight:bold;;color: var(--color-base)">Fields and applications</div><div class="sidebar-list-content mw-collapsible-content plainlist"> <ul><li><a href="/wiki/Applications_of_evolution" title="Applications of evolution">Applications of evolution</a></li> <li><a href="/wiki/Biosocial_criminology" title="Biosocial criminology">Biosocial criminology</a></li> <li><a href="/wiki/Ecological_genetics" title="Ecological genetics">Ecological genetics</a></li> <li><a href="/wiki/Evolutionary_aesthetics" title="Evolutionary aesthetics">Evolutionary aesthetics</a></li> <li><a href="/wiki/Evolutionary_anthropology" title="Evolutionary anthropology">Evolutionary anthropology</a></li> <li><a href="/wiki/Evolutionary_computation" title="Evolutionary computation">Evolutionary computation</a></li> <li><a href="/wiki/Evolutionary_ecology" title="Evolutionary ecology">Evolutionary ecology</a></li> <li><a href="/wiki/Evolutionary_economics" title="Evolutionary economics">Evolutionary economics</a></li> <li><a href="/wiki/Evolutionary_epistemology" title="Evolutionary epistemology">Evolutionary epistemology</a></li> <li><a href="/wiki/Evolutionary_ethics" title="Evolutionary ethics">Evolutionary ethics</a></li> <li><a href="/wiki/Evolutionary_game_theory" title="Evolutionary game theory">Evolutionary game theory</a></li> <li><a href="/wiki/Evolutionary_linguistics" title="Evolutionary linguistics">Evolutionary linguistics</a></li> <li><a href="/wiki/Evolutionary_medicine" title="Evolutionary medicine">Evolutionary medicine</a></li> <li><a href="/wiki/Evolutionary_neuroscience" title="Evolutionary neuroscience">Evolutionary neuroscience</a></li> <li><a href="/wiki/Evolutionary_physiology" title="Evolutionary physiology">Evolutionary physiology</a></li> <li><a href="/wiki/Evolutionary_psychology" title="Evolutionary psychology">Evolutionary psychology</a></li> <li><a href="/wiki/Experimental_evolution" title="Experimental evolution">Experimental evolution</a></li> <li><a href="/wiki/Phylogenetics" title="Phylogenetics">Phylogenetics</a></li> <li><a href="/wiki/Paleontology" title="Paleontology">Paleontology</a></li> <li><a href="/wiki/Selective_breeding" title="Selective breeding">Selective breeding</a></li> <li><a href="/wiki/Laboratory_experiments_of_speciation" title="Laboratory experiments of speciation">Speciation experiments</a></li> <li><a href="/wiki/Sociobiology" title="Sociobiology">Sociobiology</a></li> <li><a href="/wiki/Island_biogeography" class="mw-redirect" title="Island biogeography">Island biogeography</a></li> <li><a href="/wiki/Systematics" title="Systematics">Systematics</a></li> <li><a href="/wiki/Universal_Darwinism" title="Universal Darwinism">Universal Darwinism</a></li></ul></div></div></td> </tr><tr><td class="sidebar-content" style="background:transparent;"> <div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="text-align:center;padding-bottom:0;background:#90ee90;font-size:100%;font-weight:bold;;color: var(--color-base)">Social implications</div><div class="sidebar-list-content mw-collapsible-content plainlist"> <ul><li><a href="/wiki/Eugenics" title="Eugenics">Eugenics</a></li> <li><a href="/wiki/Evolution_as_fact_and_theory" title="Evolution as fact and theory">Evolution as fact and theory</a></li> <li><a href="/wiki/Dysgenics" title="Dysgenics">Dysgenics</a></li> <li><a href="/wiki/Social_effects_of_evolutionary_theory" title="Social effects of evolutionary theory">Social effects</a></li> <li><a href="/wiki/Rejection_of_evolution_by_religious_groups" title="Rejection of evolution by religious groups">Creation–evolution controversy</a></li> <li><a href="/wiki/Theistic_evolution" title="Theistic evolution">Theistic evolution</a></li> <li><a href="/wiki/Objections_to_evolution" title="Objections to evolution">Objections to evolution</a></li> <li><a href="/wiki/Level_of_support_for_evolution" title="Level of support for evolution">Level of support</a></li> <li><a href="/wiki/Nature_versus_nurture" title="Nature versus nurture">Nature-nurture controversy</a></li></ul></div></div></td> </tr><tr><td class="sidebar-below hlist"> <ul><li><span class="nowrap"><span class="nowrap"><span class="noviewer" typeof="mw:File"><a href="/wiki/File:Tree_of_life.svg" class="mw-file-description"><img alt="icon" src="//upload.wikimedia.org/wikipedia/commons/thumb/0/09/Tree_of_life.svg/16px-Tree_of_life.svg.png" decoding="async" width="16" height="13" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/0/09/Tree_of_life.svg/24px-Tree_of_life.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/0/09/Tree_of_life.svg/32px-Tree_of_life.svg.png 2x" data-file-width="915" data-file-height="760" /></a></span> </span><a href="/wiki/Portal:Evolutionary_biology" title="Portal:Evolutionary biology">Evolutionary biology portal</a></span></li> <li><span class="nowrap"><span class="noviewer" typeof="mw:File"><span title="Category"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/23px-Symbol_category_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/31px-Symbol_category_class.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <a href="/wiki/Category:Evolutionary_biology" title="Category:Evolutionary biology">Category</a></span></li></ul></td></tr><tr><td class="sidebar-navbar"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><style data-mw-deduplicate="TemplateStyles:r1239400231">.mw-parser-output .navbar{display:inline;font-size:88%;font-weight:normal}.mw-parser-output .navbar-collapse{float:left;text-align:left}.mw-parser-output .navbar-boxtext{word-spacing:0}.mw-parser-output .navbar ul{display:inline-block;white-space:nowrap;line-height:inherit}.mw-parser-output .navbar-brackets::before{margin-right:-0.125em;content:"[ "}.mw-parser-output .navbar-brackets::after{margin-left:-0.125em;content:" ]"}.mw-parser-output .navbar li{word-spacing:-0.125em}.mw-parser-output .navbar a>span,.mw-parser-output .navbar a>abbr{text-decoration:inherit}.mw-parser-output .navbar-mini abbr{font-variant:small-caps;border-bottom:none;text-decoration:none;cursor:inherit}.mw-parser-output .navbar-ct-full{font-size:114%;margin:0 7em}.mw-parser-output .navbar-ct-mini{font-size:114%;margin:0 4em}html.skin-theme-clientpref-night .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}@media(prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}}@media print{.mw-parser-output .navbar{display:none!important}}</style><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Evolutionary_biology" title="Template:Evolutionary biology"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Evolutionary_biology" title="Template talk:Evolutionary biology"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Evolutionary_biology" title="Special:EditPage/Template:Evolutionary biology"><abbr title="Edit this template">e</abbr></a></li></ul></div></td></tr></tbody></table> <p>In <a href="/wiki/Evolution" title="Evolution">evolution</a>, <b>cooperation</b> is the process where groups of organisms work or act together for common or mutual benefits. It is commonly defined as any <a href="/wiki/Adaptation" title="Adaptation">adaptation</a> that has evolved, at least in part, to increase the <a href="/wiki/Reproductive_success" title="Reproductive success">reproductive success</a> of the actor's social partners.<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> For example, territorial choruses by male <a href="/wiki/Lion" title="Lion">lions</a> discourage intruders and are likely to benefit all contributors.<sup id="cite_ref-Clutton-Brock_2009_51–57_2-0" class="reference"><a href="#cite_note-Clutton-Brock_2009_51–57-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> </p><p>This process contrasts with intragroup competition where individuals work against each other for selfish reasons. Cooperation exists not only in humans but in other animals as well. The diversity of taxa that exhibits cooperation is quite large, ranging from <a href="/wiki/Zebra" title="Zebra">zebra</a> herds to pied <a href="/wiki/Old_World_babbler" title="Old World babbler">babblers</a> to <a href="/wiki/African_elephants" class="mw-redirect" title="African elephants">African elephants</a>. Many animal and plant species cooperate with both members of their own species and with members of other species. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="In_animals">In animals</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cooperation_(evolution)&action=edit&section=1" title="Edit section: In animals"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Cooperation in animals appears to occur mostly for direct benefit or between relatives. Spending time and resources assisting a related individual may at first seem destructive to an organism's chances of survival but is actually beneficial over the long-term. Since relatives share part of the helper's genetic make-up, enhancing each individual's chance of survival may actually increase the likelihood that the helper's genetic traits will be passed on to future generations.<sup id="cite_ref-Hamilton_3-0" class="reference"><a href="#cite_note-Hamilton-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> </p><p>However, some researchers, such as ecology professor Tim Clutton-Brock, assert that cooperation is a more complex process. They state that helpers may receive more direct, and less indirect, gains from assisting others than is commonly reported. These gains include protection from predation and increased reproductive fitness. Furthermore, they insist that cooperation may not solely be an interaction between two individuals but may be part of the broader goal of unifying populations.<sup id="cite_ref-Clutton_4-0" class="reference"><a href="#cite_note-Clutton-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> </p><p>Prominent biologists, such as <a href="/wiki/Charles_Darwin" title="Charles Darwin">Charles Darwin</a>, <a href="/wiki/E._O._Wilson" title="E. O. Wilson">E. O. Wilson</a>, and <a href="/wiki/W._D._Hamilton" title="W. D. Hamilton">W. D. Hamilton</a>, have found the evolution of cooperation fascinating because <a href="/wiki/Natural_selection" title="Natural selection">natural selection</a> favors those who achieve the greatest reproductive success while <a href="/wiki/Cooperative" title="Cooperative">cooperative</a> behavior often decreases the reproductive success of the actor (the individual performing the cooperative behavior). Hence, cooperation seemed to pose a challenging problem to the theory of natural selection, which rests on the assumption that individuals compete to survive and maximize their reproductive successes.<sup id="cite_ref-Clutton-Brock_2009_51–57_2-1" class="reference"><a href="#cite_note-Clutton-Brock_2009_51–57-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> Additionally, some species have been found to perform cooperative behaviors that may at first sight seem detrimental to their own evolutionary fitness. For example, when a <a href="/wiki/Ground_squirrel" title="Ground squirrel">ground squirrel</a> sounds an alarm call to warn other group members of a nearby coyote, it draws attention to itself and increases its own odds of being eaten.<sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> There have been multiple hypotheses for the evolution of cooperation, all of which are rooted in Hamilton's models based on <a href="/wiki/Inclusive_fitness" title="Inclusive fitness">inclusive fitness</a>. These models hypothesize that cooperation is favored by natural selection due to either direct fitness benefits (mutually beneficial cooperation) or indirect fitness benefits (<a href="/wiki/Altruism_(biology)#Implications_in_evolutionary_theory" title="Altruism (biology)">altruistic cooperation</a>).<sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> As explained below, direct benefits encompass by-product benefits and enforced reciprocity, while indirect benefits (kin selection) encompass limited dispersal, kin discrimination and the greenbeard effect. </p> <div class="mw-heading mw-heading3"><h3 id="Kin_selection">Kin selection</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cooperation_(evolution)&action=edit&section=2" title="Edit section: Kin selection"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>One specific form of cooperation in animals is kin selection, which involves animals promoting the reproductive success of their kin, thereby promoting their own fitness.<sup id="cite_ref-Clutton_4-1" class="reference"><a href="#cite_note-Clutton-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span class="cite-bracket">[</span>nb 1<span class="cite-bracket">]</span></a></sup> </p><p>Different theories explaining kin selection have been proposed, including the "pay-to-stay" and "territory inheritance" hypotheses. The "pay-to-stay" theory suggests that individuals help others rear offspring in order to return the favor of the breeders allowing them to live on their land. The "territory inheritance" theory contends that individuals help in order to have improved access to breeding areas once the breeders depart.<sup id="cite_ref-10" class="reference"><a href="#cite_note-10"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup> </p><p>Studies conducted on red wolves support previous researchers' contention that helpers obtain both immediate and long-term gains from cooperative breeding.<sup id="cite_ref-Clutton_4-2" class="reference"><a href="#cite_note-Clutton-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> Researchers evaluated the consequences of red wolves' decisions to stay with their packs for extended periods of time after birth. While delayed dispersal helped other wolves' offspring, studies also found that it extended male helper wolves' life spans. This suggests that kin selection may not only benefit an individual in the long-term through increased fitness but also in the short-term through increased survival chances.<sup id="cite_ref-11" class="reference"><a href="#cite_note-11"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> </p><p>Some research suggests that individuals provide more help to closer relatives. This phenomenon is known as kin discrimination.<sup id="cite_ref-Griffin_12-0" class="reference"><a href="#cite_note-Griffin-12"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> In their meta-analysis, researchers compiled data on kin selection as mediated by genetic relatedness in 18 species, including the <a href="/wiki/Western_bluebird" title="Western bluebird">western bluebird</a>, <a href="/wiki/Pied_kingfisher" title="Pied kingfisher">pied kingfisher</a>, <a href="/wiki/Australian_magpie" title="Australian magpie">Australian magpie</a>, and <a href="/wiki/Dwarf_mongoose" class="mw-redirect" title="Dwarf mongoose">dwarf mongoose</a>. They found that different species exhibited varying degrees of kin discrimination, with the largest frequencies occurring among those who have the most to gain from cooperative interactions.<sup id="cite_ref-Griffin_12-1" class="reference"><a href="#cite_note-Griffin-12"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="In_plants">In plants</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cooperation_(evolution)&action=edit&section=3" title="Edit section: In plants"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Cooperation exists not only in animals but also in plants. In a greenhouse experiment with <i><a href="/wiki/Ipomoea_hederacea" title="Ipomoea hederacea">Ipomoea hederacea</a></i>, a climbing plant, results show that kin groups have higher efficiency rates in growth than non-kin groups do. This is expected to rise out of reduced competition within the kin groups.<sup id="cite_ref-13" class="reference"><a href="#cite_note-13"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Explanation">Explanation</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cooperation_(evolution)&action=edit&section=4" title="Edit section: Explanation"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The inclusive fitness theory provides a good overview of possible solutions to the fundamental problem of cooperation. The theory is based on the hypothesis that cooperation helps in transmitting underlying genes to future generations either through increasing the reproductive successes of the individual (direct fitness) or of other individuals who carry the same genes (indirect fitness). Direct benefits can result from simple by-product of cooperation or enforcement mechanisms, while indirect benefits can result from cooperation with genetically similar individuals.<sup id="cite_ref-Hamilton_3-1" class="reference"><a href="#cite_note-Hamilton-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Direct_fitness_benefits">Direct fitness benefits</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cooperation_(evolution)&action=edit&section=5" title="Edit section: Direct fitness benefits"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>This is also called mutually beneficial cooperation as both actor and recipient depend on direct fitness benefits, which are broken down into two different types: <a href="/wiki/Byproduct" class="mw-redirect" title="Byproduct">by-product benefit</a> and <a href="/wiki/Enforcement" title="Enforcement">enforcement</a>. </p><p>By-product benefit arises as a consequence of social partners having a shared interest in cooperation. For example, in meerkats, larger group size provides a benefit to all the members of that group by increasing survival rates, foraging success and conflict wins.<sup id="cite_ref-14" class="reference"><a href="#cite_note-14"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup> This is because living in groups is better than living alone, and cooperation arises passively as a result of many animals doing the same thing. By-product benefit can also arise as a consequence of subordinate animals staying and helping a nest that is dominated by leaders who often suffer high mortality rates. It has been shown that cooperation would be most advantageous for the sex that is more likely to remain and breed in the natal group. This is because the subordinate will have a higher chance to become dominant in the group as time passes. Cooperation in this scenario is often seen between non-related members of the same species, such as the wasp <i><a href="/wiki/Polistes_dominula" class="mw-redirect" title="Polistes dominula">Polistes dominula</a></i>.<sup id="cite_ref-15" class="reference"><a href="#cite_note-15"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup> </p><p><b>Prisoner's Delight</b>, another term to describe <b>by-product benefit</b>, is a term coined by <a href="/wiki/Kenneth_Binmore" title="Kenneth Binmore">Kenneth Binmore</a> in 2007 after he found that benefits can result as an automatic consequence of an otherwise "self-interested" act in <a href="/wiki/Cooperative_hunting" class="mw-redirect" title="Cooperative hunting">cooperative hunting</a>. He illustrated this with a scenario having two hunters, each hunter having the choice of hunting (cooperate) or not hunting (free-riding). Assuming that cooperative hunting results in greater rewards than just a one-player hunt, when hunting is not rare, both hunters and non-hunters benefit because either player is likely to be with other hunters, and thus likely to reap the rewards of a successful hunt. This situation demonstrates "Prisoner's Delight" because the food of a successful hunt is shared between the two players regardless of whether or not they participated.<sup id="cite_ref-Behavioral_Ecology_2012_16-0" class="reference"><a href="#cite_note-Behavioral_Ecology_2012-16"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> </p><p>It has been shown that <a href="/wiki/Free-rider_problem" title="Free-rider problem">free riding</a>, or reaping the benefits without any effort, is often a problem in collective action. Examples of free riding would be if an employee in a labor union pays no dues, but still benefits from union representation. In a study published in 1995, scientists found that <a href="/wiki/Panthera_leo" class="mw-redirect" title="Panthera leo">female lions</a> showed individual differences in the extent to which they participated in group-territorial conflict. Some lions consistently 'cooperated' by approaching intruders, while others 'lagged' behind to avoid the risk of fighting. Although the lead female recognized the laggards, she failed to punish them, suggesting that cooperation is not maintained by reciprocity.<sup id="cite_ref-17" class="reference"><a href="#cite_note-17"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup> </p><p>Cooperation is maintained in situations where <a href="/wiki/Free_rider_problem" class="mw-redirect" title="Free rider problem">free-riding</a> is a problem through enforcement, which is the mechanism where the actor is rewarded for cooperating or punished for not cooperating. This happens when cooperation is favored in aiding those who have helped the actors in the past. Punishment for noncooperation has been documented in <a href="/wiki/Meerkats" class="mw-redirect" title="Meerkats">meerkats</a>, where dominant females will attack and evict subordinate females who become pregnant. The pregnancy is seen as a failure to cooperate because only the dominant females are allowed to bear offspring. Dominant females will attack and kill the offspring of subordinate females if they evade <a href="/wiki/Eviction" title="Eviction">eviction</a> and eviction often leads to increased stress and decreased survival.<sup id="cite_ref-18" class="reference"><a href="#cite_note-18"><span class="cite-bracket">[</span>17<span class="cite-bracket">]</span></a></sup> </p><p>Enforcement can also be mutually beneficial, and is often called <a href="/wiki/Reciprocal_altruism" title="Reciprocal altruism">reciprocal cooperation</a> because the act of cooperation is preferentially directed at individuals who have helped the actor in the past (directly), or helped those who have helped the actor in the past (indirectly).<sup id="cite_ref-19" class="reference"><a href="#cite_note-19"><span class="cite-bracket">[</span>18<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Indirect_fitness_benefits">Indirect fitness benefits</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cooperation_(evolution)&action=edit&section=6" title="Edit section: Indirect fitness benefits"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The second class of explanations for cooperation is indirect fitness benefits, or <a href="/wiki/Altruism_(biology)" title="Altruism (biology)">altruistic</a> cooperation. There are three major mechanisms that generate this type of fitness benefit: <a href="/wiki/Biological_dispersal" title="Biological dispersal">limited dispersal</a>, <a href="/wiki/Kin_discrimination" class="mw-redirect" title="Kin discrimination">kin discrimination</a> and the <a href="/wiki/Green-beard_effect" title="Green-beard effect">green-beard effect</a>. </p><p>Hamilton originally suggested that high relatedness could arise in two ways: direct kin recognition between individuals or limited dispersal, or population viscosity, which can keep relatives together.<sup id="cite_ref-20" class="reference"><a href="#cite_note-20"><span class="cite-bracket">[</span>19<span class="cite-bracket">]</span></a></sup> The easiest way to generate relatedness between social partners is limited dispersal, a mechanism in which genetic similarity correlates with spatial proximity. If individuals do not move far, then kin usually surrounds them. Hence, any act of altruism would be directed primarily towards kin. This mechanism has been shown in <i><a href="/wiki/Pseudomonas_aeruginosa" title="Pseudomonas aeruginosa">Pseudomonas aeruginosa</a></i> bacteria, where cooperation is disfavored when populations are well mixed, but favored when there is high local relatedness.<sup id="cite_ref-21" class="reference"><a href="#cite_note-21"><span class="cite-bracket">[</span>20<span class="cite-bracket">]</span></a></sup> </p><p>Kin discrimination also influences cooperation because the actor can give aid preferentially towards related partners. Since kin usually share common genes, it is thought that this nepotism can lead to genetic relatedness between the actor and the partner's offspring, which affects the cooperation an actor might give. </p><p>This mechanism is similar to what happens with the <a href="/wiki/Green-beard_effect" title="Green-beard effect">green-beard effect</a>, but with the green-beard effect, the actor has to instead identify which of its social partners share the gene for cooperation. A green-beard system must always co-occur within individuals and alleles to produce a perceptible trait, recognition of this trait in others, and preferential treatment to those recognized. Examples of green-beard behavior have been found in <a href="/wiki/Hydrozoans" class="mw-redirect" title="Hydrozoans">hydrozoans</a>, <a href="/wiki/Slime_molds" class="mw-redirect" title="Slime molds">slime molds</a>, <a href="/wiki/Yeast" title="Yeast">yeast</a>, and <a href="/wiki/Ants" class="mw-redirect" title="Ants">ants</a>. An example is in <a href="/wiki/Uta_stansburiana" class="mw-redirect" title="Uta stansburiana">side-blotch lizards</a>, where blue-throated males preferentially establish territories next to each other. Results show that neighboring blue-throats are more successful at mate guarding. However, blue males next to larger, more aggressive orange males suffer a cost.<sup id="cite_ref-22" class="reference"><a href="#cite_note-22"><span class="cite-bracket">[</span>21<span class="cite-bracket">]</span></a></sup> This strategy blue has evolutionary cycles of altruism alternating with mutualism tied to the RPS game. </p> <div class="mw-heading mw-heading2"><h2 id="Multi-level_selection">Multi-level selection</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cooperation_(evolution)&action=edit&section=7" title="Edit section: Multi-level selection"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Multi-level_selection" class="mw-redirect" title="Multi-level selection">Multi-level selection</a></div> <p>Multi-level selection theory suggests that selection operates on more than one level: for example, it may operate at an atomic and molecular level in cells, at the level of cells in the body, and then again at the whole organism level, and the community level, and the species level. Any level which is not competitive with others of the same level will be eliminated, even if the level below is highly competitive. A classic example is that of genes which prevent <a href="/wiki/Cancer" title="Cancer">cancer</a>. Cancer cells divide uncontrollably, and at the cellular level, they are very successful, because they are (in the short term) reproducing very well and out competing other cells in the body. However, at the whole organism level, cancer is often fatal, and so may prevent reproduction. Therefore, changes to the genome which prevent cancer (for example, by causing damaged cells to act co-operatively by destroying themselves) are favoured. Multi-level selection theory contends that similar effects can occur, for example, to cause individuals to co-operate to avoid behaviours which favour themselves short-term, but destroy the community (and their descendants) long term. </p> <div class="mw-heading mw-heading2"><h2 id="Market_effect">Market effect</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cooperation_(evolution)&action=edit&section=8" title="Edit section: Market effect"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>One theory suggesting a mechanism that could lead to the evolution of co-operation is the "market effect" as suggested by Noe and Hammerstein.<sup id="cite_ref-Noe_&_Hammerstein,_1994_23-0" class="reference"><a href="#cite_note-Noe_&_Hammerstein,_1994-23"><span class="cite-bracket">[</span>22<span class="cite-bracket">]</span></a></sup> The mechanism relies on the fact that in many situations there exists a <a href="/wiki/Trade-off" title="Trade-off">trade-off</a> between efficiency obtaining a desired resource and the amount of resources one can actively obtain. In that case, each partner in a system could benefit from specializing in producing one specific resource and obtaining the other resource by <a href="/wiki/Trade" title="Trade">trade</a>. When only two partners exist, each can specialize in one <a href="/wiki/Resource_(economics)" class="mw-redirect" title="Resource (economics)">resource</a>, and trade for the other. Trading for the resource requires co-operation with the other partner and includes a process of bidding and bargaining. </p><p>This mechanism can be relied to both within a species or social group and within species systems. It can also be applied to a multi-partner system, in which the owner of a resource has the power to choose its co-operation partner. This model can be applied in natural systems (examples exist in the world of apes, cleaner fish, and more). Easy for exemplifying, though, are systems from international trading. Arabic countries control vast amounts of oil, but seek technologies from western countries. These in turn are in need of Arab oil. The solution is co-operation by trade. </p> <div class="mw-heading mw-heading2"><h2 id="Symbiosis">Symbiosis</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cooperation_(evolution)&action=edit&section=9" title="Edit section: Symbiosis"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><a href="/wiki/Symbiosis" title="Symbiosis">Symbiosis</a> refers to two or more biological species that interact closely, often over a long period of time. Symbiosis includes three types of interactions—<a href="/wiki/Mutualism_(biology)" title="Mutualism (biology)">mutualism</a>, <a href="/wiki/Commensalism" title="Commensalism">commensalism</a>, and <a href="/wiki/Parasitism" title="Parasitism">parasitism</a>—of which only mutualism can sometimes qualify as cooperation. Mutualism involves a close, mutually beneficial interaction between two different biological species, whereas "cooperation" is a more general term that can involve looser interactions and can be interspecific (between species) or intraspecific (within a species). In commensalism, one of the two participating species benefits, while the other is neither harmed nor benefitted. In parasitism, one of the two participating species benefits at the expense of the other. </p><p>Symbiosis may be obligate or facultative. In obligate symbiosis, one or both species depends on the other for survival. In facultative symbiosis, the symbiotic interaction is not necessary for the survival of either species. </p><p>Two special types of symbiosis include <a href="/wiki/Endosymbiont" title="Endosymbiont">endosymbiosis</a>, in which one species lives inside of another, and ectosymbiosis, in which one species lives on another. </p> <div class="mw-heading mw-heading3"><h3 id="Mutualism">Mutualism</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cooperation_(evolution)&action=edit&section=10" title="Edit section: Mutualism"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Rhizobia_nodules_on_Vigna_unguiculata.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/a/a5/Rhizobia_nodules_on_Vigna_unguiculata.jpg/220px-Rhizobia_nodules_on_Vigna_unguiculata.jpg" decoding="async" width="220" height="147" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/a/a5/Rhizobia_nodules_on_Vigna_unguiculata.jpg/330px-Rhizobia_nodules_on_Vigna_unguiculata.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/a/a5/Rhizobia_nodules_on_Vigna_unguiculata.jpg/440px-Rhizobia_nodules_on_Vigna_unguiculata.jpg 2x" data-file-width="1000" data-file-height="667" /></a><figcaption><a href="/wiki/Rhizobia" title="Rhizobia">Rhizobia</a> nodules on <i><a href="/wiki/Vigna_unguiculata" class="mw-redirect" title="Vigna unguiculata">Vigna unguiculata</a></i></figcaption></figure> <p><a href="/wiki/Mutualism_(biology)" title="Mutualism (biology)">Mutualism</a> is a form of symbiosis in which both participating species benefit. </p><p>A classic example of mutualism is the interaction between <a href="/wiki/Rhizobia" title="Rhizobia">rhizobia</a> soil bacteria and legumes (<a href="/wiki/Fabaceae" title="Fabaceae">Fabaceae</a>). In this interaction, rhizobia bacteria induce root nodule formation in legume plants via an exchange of molecular signals.<sup id="cite_ref-Advances_in_Agronomy_24-0" class="reference"><a href="#cite_note-Advances_in_Agronomy-24"><span class="cite-bracket">[</span>23<span class="cite-bracket">]</span></a></sup> Within the root nodules, rhizobia fix atmospheric nitrogen into ammonia using the <a href="/wiki/Nitrogenase" title="Nitrogenase">nitrogenase</a> enzyme. The legume benefits from a new supply of usable nitrogen from the rhizobia, and the rhizobia benefits from organic acid energy sources from the plant as well as the protection provided by the root nodule. Since the rhizobia live within the legume, this is an example of endosymbiosis, and since both the bacteria and the plant can survive independently, it is also an example of facultative symbiosis. </p><p><a href="/wiki/Lichen" title="Lichen">Lichens</a> are another example of mutualism. Lichens consist of a <a href="/wiki/Fungus" title="Fungus">fungus</a> (the mycobiont) and a photosynthetic partner (the photobiont), which is usually a <a href="/wiki/Green_alga" class="mw-redirect" title="Green alga">green alga</a> or a <a href="/wiki/Cyanobacteria" title="Cyanobacteria">cyanobacteria</a>. The mycobiont benefits from the sugar products of <a href="/wiki/Photosynthesis" title="Photosynthesis">photosynthesis</a> generated by the photobiont, and the photobiont benefits from the increased water retention and increased surface area to capture water and mineral nutrients conferred by the mycobiont. Many lichens are examples of obligate symbiosis. In fact, one-fifth of all known extant fungal species form obligate symbiotic associations with green algae, cyanobacteria or both.<sup id="cite_ref-Lichens_25-0" class="reference"><a href="#cite_note-Lichens-25"><span class="cite-bracket">[</span>24<span class="cite-bracket">]</span></a></sup> </p><p>Not all examples of mutualism are also examples of cooperation. Specifically, in by-product mutualism, both participants benefit, but cooperation is not involved. For example, when an elephant defecates, this is beneficial to the elephant as a way to empty waste, and it is also beneficial to a dung beetle that uses the elephant's dung. However, neither participant's behavior yields a benefit from the other, and thus cooperation is not taking place.<sup id="cite_ref-Elephant_Dung_26-0" class="reference"><a href="#cite_note-Elephant_Dung-26"><span class="cite-bracket">[</span>25<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Hidden_benefits">Hidden benefits</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cooperation_(evolution)&action=edit&section=11" title="Edit section: Hidden benefits"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><b>Hidden benefits</b> are benefits from cooperation that are not obvious because they are obscure or delayed. (For example, a hidden benefit would not involve an increase in the number of offspring or offspring viability.) </p><p>One example of a hidden benefit involves <i>Malarus cyaneus</i>, the <a href="/wiki/Superb_fairy-wren" class="mw-redirect" title="Superb fairy-wren">superb fairy-wren</a>. In <i>M. cyaneus</i>, the presence of helpers at the nest does not lead to an increase in chick mass. However, the presence of helpers does confer a hidden benefit: it increases the chance that a mother will survive to breed in the next year.<sup id="cite_ref-Behavioral_Ecology_2012_16-1" class="reference"><a href="#cite_note-Behavioral_Ecology_2012-16"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> </p><p>Another example of a hidden benefit is indirect reciprocity, in which a donor individual helps a beneficiary to increase the probability that observers will invest in the donor in the future, even when the donor will have no further interaction with the beneficiary. </p><p>In a study of 79 students, participants played a game in which they could repeatedly give money to others and receive from others. They were told that they would never interact with the same person in the reciprocal role. A player's history of donating was displayed at each anonymous interaction, and donations were significantly more frequent to receivers who had been generous to others in earlier interactions.<sup id="cite_ref-Cooperation_Through_Image_Scoring_27-0" class="reference"><a href="#cite_note-Cooperation_Through_Image_Scoring-27"><span class="cite-bracket">[</span>26<span class="cite-bracket">]</span></a></sup> Indirect reciprocity has only been shown to occur in humans.<sup id="cite_ref-Behavioural_Processes_28-0" class="reference"><a href="#cite_note-Behavioural_Processes-28"><span class="cite-bracket">[</span>27<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Prisoner's_dilemma"><span id="Prisoner.27s_dilemma"></span>Prisoner's dilemma</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cooperation_(evolution)&action=edit&section=12" title="Edit section: Prisoner's dilemma"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Prisoner%27s_dilemma" title="Prisoner's dilemma">Prisoner's dilemma</a></div> <figure class="mw-halign-left" typeof="mw:File/Thumb"><a href="/wiki/File:Canis_lupus_pack_surrounding_Bison.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/4/45/Canis_lupus_pack_surrounding_Bison.jpg/200px-Canis_lupus_pack_surrounding_Bison.jpg" decoding="async" width="200" height="162" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/4/45/Canis_lupus_pack_surrounding_Bison.jpg/300px-Canis_lupus_pack_surrounding_Bison.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/4/45/Canis_lupus_pack_surrounding_Bison.jpg/400px-Canis_lupus_pack_surrounding_Bison.jpg 2x" data-file-width="599" data-file-height="484" /></a><figcaption>Cooperative hunting by wolves allows them to tackle much larger and more nutritious prey than any individual wolf could handle. However, such cooperation could, potentially, be exploited by selfish individuals who do not expose themselves to the dangers of the hunt, but nevertheless share in the spoils.</figcaption></figure> <p>Even if all members of a group benefit from cooperation, individual self-interest may not favor cooperation. The <a href="/wiki/Prisoner%27s_dilemma" title="Prisoner's dilemma">prisoner's dilemma</a> codifies this problem and has been the subject of much research, both theoretical and experimental. In its original form the prisoner's dilemma game (PDG) described two awaiting trial prisoners, A and B, each faced with the choice of betraying the other or remaining silent. The "<a href="/wiki/Game_theory" title="Game theory">game</a>" has four possible outcomes: (a) they both betray each other, and are both sentenced to two years in prison; (b) A betrays B, which sets A free and B is sentenced to four years in prison; (c) B betrays A, with the same result as (b) except that it is B who is set free and the other spends four years in jail; (d) both remain silent, resulting in a six-month sentence each. Clearly (d) ("cooperation") is the best mutual strategy, but from the point of view of the individual betrayal is unbeatable (resulting in being set free, or getting only a two-year sentence). Remaining silent results in a four-year or six-month sentence. This is exemplified by a further example of the PDG: two strangers attend a restaurant together and decide to split the bill. The mutually best ploy would be for both parties to order the cheapest items on the menu (mutual cooperation). But if one member of the party exploits the situation by ordering the most expensive items, then it is best for the other member to do likewise. In fact, if the fellow diner's personality is completely unknown, and the two diners are unlikely ever to meet again, it is always in one's own best interests to eat as expensively as possible. Situations in nature that are subject to the same dynamics (rewards and penalties) as the PDG define cooperative behavior: it is never in the individual's fitness interests to cooperate, even though mutual cooperation rewards the two contestants (together) more highly than any other strategy.<sup id="cite_ref-sigmund_29-0" class="reference"><a href="#cite_note-sigmund-29"><span class="cite-bracket">[</span>28<span class="cite-bracket">]</span></a></sup> As described in the <a href="/wiki/Nash_equilibrium" title="Nash equilibrium">Nash equilibrium</a>, cooperation cannot evolve under these circumstances. </p><p>However, in 1981 <a href="/wiki/Robert_Axelrod_(political_scientist)" title="Robert Axelrod (political scientist)">Axelrod</a> and <a href="/wiki/W._D._Hamilton" title="W. D. Hamilton">Hamilton</a><sup id="cite_ref-axelrod_30-0" class="reference"><a href="#cite_note-axelrod-30"><span class="cite-bracket">[</span>29<span class="cite-bracket">]</span></a></sup> noted that if the same contestants in the PDG meet repeatedly (in the so-called iterated prisoner's dilemma game, IPD) then tit-for-tat (foreshadowed by <a href="/wiki/Robert_Trivers" title="Robert Trivers">Robert Trivers</a>' 1971 reciprocal altruism theory<sup id="cite_ref-31" class="reference"><a href="#cite_note-31"><span class="cite-bracket">[</span>30<span class="cite-bracket">]</span></a></sup>) is a robust strategy which promotes altruism.<sup id="cite_ref-sigmund_29-1" class="reference"><a href="#cite_note-sigmund-29"><span class="cite-bracket">[</span>28<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-axelrod_30-1" class="reference"><a href="#cite_note-axelrod-30"><span class="cite-bracket">[</span>29<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-32" class="reference"><a href="#cite_note-32"><span class="cite-bracket">[</span>31<span class="cite-bracket">]</span></a></sup> In "tit-for-tat" both players' opening moves are cooperation. Thereafter each contestant repeats the other player's last move, resulting in a seemingly endless sequence of mutually cooperative moves. However, mistakes severely undermine tit-for-tat's effectiveness, giving rise to prolonged sequences of betrayal, which can only be rectified by another mistake. Since these initial discoveries, all the other possible IPD game strategies have been identified (16 possibilities in all, including, for instance, "generous tit-for-tat", which behaves like "tit-for-tat", except that it cooperates with a small probability when the opponent's last move was "betray".<sup id="cite_ref-33" class="reference"><a href="#cite_note-33"><span class="cite-bracket">[</span>32<span class="cite-bracket">]</span></a></sup>), but all can be outperformed by at least one of the other strategies, should one of the players switch to such a strategy. The result is that none is <a href="/wiki/Evolutionarily_stable_strategy" title="Evolutionarily stable strategy">evolutionarily stable</a>, and any prolonged series of the iterated prisoner's dilemma game, in which alternative strategies arise at random, gives rise to a chaotic sequence of strategy changes that never ends.<sup id="cite_ref-sigmund_29-2" class="reference"><a href="#cite_note-sigmund-29"><span class="cite-bracket">[</span>28<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-34" class="reference"><a href="#cite_note-34"><span class="cite-bracket">[</span>33<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-koeslag1_35-0" class="reference"><a href="#cite_note-koeslag1-35"><span class="cite-bracket">[</span>34<span class="cite-bracket">]</span></a></sup> </p><p>Results from <a href="/wiki/Experimental_economics" title="Experimental economics">experimental economics</a> show, however, that humans often act more cooperatively than strict self-interest would dictate.<sup id="cite_ref-36" class="reference"><a href="#cite_note-36"><span class="cite-bracket">[</span>35<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Evolutionary_mechanisms_suggesting_that_reciprocity_is_the_result,_not_the_cause,_of_the_evolution_of_cooperation"><span id="Evolutionary_mechanisms_suggesting_that_reciprocity_is_the_result.2C_not_the_cause.2C_of_the_evolution_of_cooperation"></span>Evolutionary mechanisms suggesting that reciprocity is the result, not the cause, of the evolution of cooperation</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cooperation_(evolution)&action=edit&section=13" title="Edit section: Evolutionary mechanisms suggesting that reciprocity is the result, not the cause, of the evolution of cooperation"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>In the light of the iterated prisoner's dilemma game and the reciprocal altruism theory failing to provide full answers to the evolutionary stability of cooperation, several alternative explanations have been proposed. </p> <figure class="mw-halign-left" typeof="mw:File/Thumb"><a href="/wiki/File:Paonroue.JPG" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/0/05/Paonroue.JPG/300px-Paonroue.JPG" decoding="async" width="300" height="225" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/0/05/Paonroue.JPG/450px-Paonroue.JPG 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/0/05/Paonroue.JPG/600px-Paonroue.JPG 2x" data-file-width="2048" data-file-height="1536" /></a><figcaption>A male peacock with its beautiful but clumsy, aerodynamically unsound erectile tail, which <a href="/wiki/Amotz_Zahavi" title="Amotz Zahavi">Amotz Zahavi</a> believes is a handicap, comparable to a race horse's handicap. The larger the handicap the more intrinsically fit the individual (see text).</figcaption></figure> <figure class="mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Curlin_in_the_Final_Turn_in_the_2008_Stephen_Foster_Handicap_(2972085393).jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/b/b7/Curlin_in_the_Final_Turn_in_the_2008_Stephen_Foster_Handicap_%282972085393%29.jpg/300px-Curlin_in_the_Final_Turn_in_the_2008_Stephen_Foster_Handicap_%282972085393%29.jpg" decoding="async" width="300" height="137" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/b/b7/Curlin_in_the_Final_Turn_in_the_2008_Stephen_Foster_Handicap_%282972085393%29.jpg/450px-Curlin_in_the_Final_Turn_in_the_2008_Stephen_Foster_Handicap_%282972085393%29.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/b/b7/Curlin_in_the_Final_Turn_in_the_2008_Stephen_Foster_Handicap_%282972085393%29.jpg/600px-Curlin_in_the_Final_Turn_in_the_2008_Stephen_Foster_Handicap_%282972085393%29.jpg 2x" data-file-width="887" data-file-height="404" /></a><figcaption>The best horses in a <a href="/wiki/Handicap_(horse_racing)" title="Handicap (horse racing)">handicap race</a> carry the largest weights, so the size of the handicap is a measure of the animal's quality.</figcaption></figure> <p>There are striking parallels between cooperative behavior and exaggerated <a href="/wiki/Sexual_selection" title="Sexual selection">sexual ornaments</a> displayed by some animals, particularly certain birds, such as, amongst others, the <a href="/wiki/Peafowl" title="Peafowl">peacock</a>. Both are costly in fitness terms, and both are generally conspicuous to other members of the population or species. This led <a href="/wiki/Amotz_Zahavi" title="Amotz Zahavi">Amotz Zahavi</a> to suggest that both might be <a href="/wiki/Signalling_theory" title="Signalling theory">fitness signals</a> rendered evolutionarily stable by his <a href="/wiki/Handicap_principle" title="Handicap principle">handicap principle</a>.<sup id="cite_ref-37" class="reference"><a href="#cite_note-37"><span class="cite-bracket">[</span>36<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-zahavi_38-0" class="reference"><a href="#cite_note-zahavi-38"><span class="cite-bracket">[</span>37<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-39" class="reference"><a href="#cite_note-39"><span class="cite-bracket">[</span>38<span class="cite-bracket">]</span></a></sup> If a signal is to remain reliable, and generally resistant to falsification, <a href="/wiki/Signalling_theory#Sports_handicapping_metaphor" title="Signalling theory">the signal</a> has to be evolutionarily costly.<sup id="cite_ref-40" class="reference"><a href="#cite_note-40"><span class="cite-bracket">[</span>39<span class="cite-bracket">]</span></a></sup> Thus, if a (low fitness) liar were to use the highly costly signal, which seriously eroded its real fitness, it would find it difficult to maintain a semblance or normality.<sup id="cite_ref-41" class="reference"><a href="#cite_note-41"><span class="cite-bracket">[</span>40<span class="cite-bracket">]</span></a></sup> Zahavi borrowed the term "handicap principle" from sports handicapping systems. These systems are aimed at reducing disparities in performance, thereby making the outcome of contests less predictable. In a horse <a href="/wiki/Handicap_(horse_racing)" title="Handicap (horse racing)">handicap race</a>, provenly faster horses are given heavier weights to carry under their saddles than inherently slower horses. Similarly, in <a href="/wiki/Golf_handicap" class="mw-redirect" title="Golf handicap">amateur golf</a>, better golfers have fewer strokes subtracted from their raw scores than the less talented players. The handicap therefore correlates with unhandicapped performance, making it possible, if one knows nothing about the horses, to predict which unhandicapped horse would win an open race. It would be the one handicapped with the greatest weight in the saddle. The handicaps in nature are highly visible, and therefore a peahen, for instance, would be able to deduce the health of a potential mate by comparing its handicap (the size of the peacock's tail) with those of the other males. The loss of the male's fitness caused by the handicap is offset by his increased access to females, which is as much of a fitness concern as is his health. A cooperative act is, by definition, similarly costly (e.g. helping raise the young at the nest of an unrelated pair of birds versus producing and raising one's own offspring). It would therefore also signal fitness, and is probably as attractive to females as a physical handicap. If this is the case, cooperation is evolutionarily stabilized by <a href="/wiki/Sexual_selection" title="Sexual selection">sexual selection</a>.<sup id="cite_ref-zahavi_38-1" class="reference"><a href="#cite_note-zahavi-38"><span class="cite-bracket">[</span>37<span class="cite-bracket">]</span></a></sup> </p> <figure class="mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Flickr_-_Rainbirder_-_African_pygmy-kingfisher_(Ceyx_pictus).jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Flickr_-_Rainbirder_-_African_pygmy-kingfisher_%28Ceyx_pictus%29.jpg/300px-Flickr_-_Rainbirder_-_African_pygmy-kingfisher_%28Ceyx_pictus%29.jpg" decoding="async" width="300" height="196" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Flickr_-_Rainbirder_-_African_pygmy-kingfisher_%28Ceyx_pictus%29.jpg/450px-Flickr_-_Rainbirder_-_African_pygmy-kingfisher_%28Ceyx_pictus%29.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Flickr_-_Rainbirder_-_African_pygmy-kingfisher_%28Ceyx_pictus%29.jpg/600px-Flickr_-_Rainbirder_-_African_pygmy-kingfisher_%28Ceyx_pictus%29.jpg 2x" data-file-width="800" data-file-height="522" /></a><figcaption>An <a href="/wiki/African_pygmy_kingfisher" title="African pygmy kingfisher">African pygmy kingfisher</a>, showing details of appearance and coloration that are shared by all African pygmy kingfishers to a high degree of fidelity.<sup id="cite_ref-42" class="reference"><a href="#cite_note-42"><span class="cite-bracket">[</span>41<span class="cite-bracket">]</span></a></sup></figcaption></figure> <p>There is an alternate strategy for identifying fit mates which does not rely on one gender having exaggerated sexual ornaments or other handicaps, but is probably generally applicable to most, if not all sexual creatures. It derives from the concept that the change in appearance and functionality caused by a <a href="/wiki/Silent_mutation" title="Silent mutation">non-silent</a> <a href="/wiki/Mutation" title="Mutation">mutation</a> will generally stand out in a population. This is because that altered appearance and functionality will be unusual, peculiar, and different from the norm within that population. The norm against which these unusual features are judged is made up of fit attributes that have attained their plurality through <a href="/wiki/Natural_selection" title="Natural selection">natural selection</a>, while less well adapted attributes will be in the minority or frankly rare.<sup id="cite_ref-fisher_43-0" class="reference"><a href="#cite_note-fisher-43"><span class="cite-bracket">[</span>42<span class="cite-bracket">]</span></a></sup> Since the overwhelming majority of mutant features are maladaptive, and it is impossible to predict evolution's future direction, sexual creatures would be expected to <a href="/wiki/Koinophilia" title="Koinophilia">prefer mates with the fewest unusual or minority features</a>.<sup id="cite_ref-fisher_43-1" class="reference"><a href="#cite_note-fisher-43"><span class="cite-bracket">[</span>42<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-44" class="reference"><a href="#cite_note-44"><span class="cite-bracket">[</span>43<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-Langlois_&_Roggman,_1990_45-0" class="reference"><a href="#cite_note-Langlois_&_Roggman,_1990-45"><span class="cite-bracket">[</span>44<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-Koeslag,_1990_46-0" class="reference"><a href="#cite_note-Koeslag,_1990-46"><span class="cite-bracket">[</span>45<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-unnikrishnan_47-0" class="reference"><a href="#cite_note-unnikrishnan-47"><span class="cite-bracket">[</span>46<span class="cite-bracket">]</span></a></sup> This will have the effect of a sexual population rapidly shedding peripheral phenotypic features, thereby canalizing the entire outward appearance and behavior of all of its members. They will all very quickly begin to look remarkably similar to one another in every detail, as illustrated in the accompanying photograph of the <a href="/wiki/African_pygmy_kingfisher" title="African pygmy kingfisher">African pygmy kingfisher</a>, <i>Ispidina picta</i>. Once a population has become as homogeneous in appearance as is typical of most species, its entire repertoire of behaviors will also be rendered <a href="/wiki/Evolutionarily_stable_strategy" title="Evolutionarily stable strategy">evolutionarily stable</a>, including any cooperative, altruistic and social interactions. Thus, in the example <a href="/wiki/Co-operation_(evolution)#The_Prisoner's_Dilemma" class="mw-redirect" title="Co-operation (evolution)">above</a> of the selfish individual who hangs back from the rest of the hunting pack, but who nevertheless joins in the spoils, that individual will be recognized as being different from the norm, and will therefore find it difficult to attract a mate (<a href="/wiki/Koinophilia" title="Koinophilia">koinophilia</a>).<sup id="cite_ref-Koeslag,_1990_46-1" class="reference"><a href="#cite_note-Koeslag,_1990-46"><span class="cite-bracket">[</span>45<span class="cite-bracket">]</span></a></sup> Its genes will therefore have only a very small probability of being passed on to the next generation, thus evolutionarily stabilizing cooperation and social interactions at whatever level of complexity is the norm in that population.<sup id="cite_ref-koeslag1_35-1" class="reference"><a href="#cite_note-koeslag1-35"><span class="cite-bracket">[</span>34<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-48" class="reference"><a href="#cite_note-48"><span class="cite-bracket">[</span>47<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="History_of_cooperation_research">History of cooperation research</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cooperation_(evolution)&action=edit&section=14" title="Edit section: History of cooperation research"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>One of the first references to animal cooperation was made by <a href="/wiki/Charles_Darwin" title="Charles Darwin">Charles Darwin</a>, who noted it as a potential problem for his theory of natural selection.<sup id="cite_ref-49" class="reference"><a href="#cite_note-49"><span class="cite-bracket">[</span>48<span class="cite-bracket">]</span></a></sup> In most of the 19th century, intellectuals like <a href="/wiki/Thomas_Henry_Huxley" title="Thomas Henry Huxley">Thomas Henry Huxley</a> and <a href="/wiki/Peter_Kropotkin" title="Peter Kropotkin">Peter Kropotkin</a> debated fervently on whether animals cooperate with one another and whether animals displayed altruistic behaviors.<sup id="cite_ref-50" class="reference"><a href="#cite_note-50"><span class="cite-bracket">[</span>49<span class="cite-bracket">]</span></a></sup> </p><p>In the late 1900s, some early research in animal cooperation focused on the benefits of group-living. While living in a group produces costs in the form of increased frequency of predator attacks and greater mating competition, some animals find that the benefits outweigh the costs. Animals that practice group-living often benefit from assistance in parasite removal, access to more mates, and conservation of energy in foraging.<sup id="cite_ref-51" class="reference"><a href="#cite_note-51"><span class="cite-bracket">[</span>50<span class="cite-bracket">]</span></a></sup> Initially, the most obvious form of animal cooperation was <a href="/wiki/Cooperation#Kin_selection" title="Cooperation">kin selection</a>, but more recent studies focus on non-kin cooperation, where benefits may seem less obvious. Non-kin cooperation often involves many strategies that include manipulation and coercion, making these interactions more complicated to study.<sup id="cite_ref-Clutton-Brock_2009_51–57_2-2" class="reference"><a href="#cite_note-Clutton-Brock_2009_51–57-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> An example of manipulation is presented by the cuckoo, a <a href="/wiki/Brood_parasite" class="mw-redirect" title="Brood parasite">brood parasite</a>, which lays its eggs in the nest of a bird of another species.<sup id="cite_ref-Behavioral_Ecology_2012_16-2" class="reference"><a href="#cite_note-Behavioral_Ecology_2012-16"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> That bird then is tricked into feeding and caring for the cuckoo offspring. Although this phenomenon may look like cooperation at first glance, it only presents benefits to one recipient. </p><p>In the past, simple <a href="/wiki/Game_theory" title="Game theory">game theory</a> models, such as the classic cooperative hunting and <a href="/wiki/Prisoner%27s_dilemma" title="Prisoner's dilemma">Prisoner's dilemma</a> models, were used to determine decisions made by animals in cooperative relationships. However, complicated interactions between animals have required the use of more complex economic models such as the <a href="/wiki/Nash_equilibrium" title="Nash equilibrium">Nash equilibrium</a>. The <a href="/wiki/Nash_equilibrium" title="Nash equilibrium">Nash equilibrium</a> is a type of non-cooperative game theory that assumes an individual's decision is influenced by its knowledge of the strategies of other individuals. This theory was novel because it took into consideration the higher cognitive capabilities of animals.<sup id="cite_ref-52" class="reference"><a href="#cite_note-52"><span class="cite-bracket">[</span>51<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-53" class="reference"><a href="#cite_note-53"><span class="cite-bracket">[</span>52<span class="cite-bracket">]</span></a></sup> The <a href="/wiki/Evolutionarily_stable_strategy" title="Evolutionarily stable strategy">evolutionarily stable strategy</a> is a refined version of the <a href="/wiki/Nash_equilibrium" title="Nash equilibrium">Nash equilibrium</a> in that it assumes strategies are heritable and are subject to natural selection. Economic models are useful for analyzing cooperative relationships because they provide predictions on how individuals act when cooperation is an option. Economic models are not perfect, but they provide a general idea of how cooperative relationships work. </p><p>Contrary to the mainstream dogma, a recently published article.<sup id="cite_ref-54" class="reference"><a href="#cite_note-54"><span class="cite-bracket">[</span>53<span class="cite-bracket">]</span></a></sup> using agent-based models demonstrates that several crucial mechanisms, such as kin selection, punishment, multilevel selection, and spatial structure, cannot rescue the evolution of cooperation. The new findings revive a long-standing puzzle in the evolution theory. In addition, the work has potential therapeutic benefits for numerous incurable diseases. </p> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cooperation_(evolution)&action=edit&section=15" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1184024115">.mw-parser-output .div-col{margin-top:0.3em;column-width:30em}.mw-parser-output .div-col-small{font-size:90%}.mw-parser-output .div-col-rules{column-rule:1px solid #aaa}.mw-parser-output .div-col dl,.mw-parser-output .div-col ol,.mw-parser-output .div-col ul{margin-top:0}.mw-parser-output .div-col li,.mw-parser-output .div-col dd{page-break-inside:avoid;break-inside:avoid-column}</style><div class="div-col" style="column-width: 22em;"> <ul><li><a href="/wiki/Agreeableness" title="Agreeableness">Agreeableness</a></li> <li><a href="/wiki/Collaboration" title="Collaboration">Collaboration</a></li> <li><a href="/wiki/Dunbar%27s_number" title="Dunbar's number">Dunbar's number</a></li> <li><a href="/wiki/Evolution_of_cooperation" class="mw-redirect" title="Evolution of cooperation">Evolution of cooperation</a></li> <li><a href="/wiki/Management_cybernetics" title="Management cybernetics">Management cybernetics</a></li> <li><a href="/wiki/Microbial_Cooperation" class="mw-redirect" title="Microbial Cooperation">Microbial Cooperation</a></li> <li><i><a href="/wiki/Mutual_Aid:_A_Factor_of_Evolution" title="Mutual Aid: A Factor of Evolution">Mutual Aid: A Factor of Evolution</a></i> by <a href="/wiki/Peter_Kropotkin" title="Peter Kropotkin">Peter Kropotkin</a></li> <li><a href="/wiki/Polytely" title="Polytely">Polytely</a></li> <li><a href="/wiki/Teamwork" title="Teamwork">Teamwork</a></li></ul></div> <div class="mw-heading mw-heading2"><h2 id="Notes">Notes</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cooperation_(evolution)&action=edit&section=16" title="Edit section: Notes"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist"> <div class="mw-references-wrap"><ol class="references"> <li id="cite_note-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-9">^</a></b></span> <span class="reference-text">An individual's gene complement (or genome) can be represented by the letters of the alphabet. Each letter is represented twice: A<sub>1</sub> and A<sub>2</sub>. This individual's genome therefore consists of 52 genes. The subscript indicates from which parent that copy of A has come. Mostly the two copies are identical, but occasionally they differ slightly. When this individual reproduces sexually, one or other copy of A (chosen randomly) is passed on to offspring-1, who gets its other copy of A from the sexual partner. The same happens with genes B, C, D, ..., Z. If we denote the two sexual partners by means of subscripts "m" and "f", then the genome of the offspring they produce might consist of A<sub>m2</sub>/A<sub>f1</sub>, B<sub>m2</sub>/B<sub>f2</sub>, C<sub>m1</sub>/C<sub>f1</sub>, D<sub>m1</sub>/D<sub>f1</sub> ... Z<sub>m1</sub>/Z<sub>f2</sub>. Each parent has contributed exactly half of the offspring's genome. So individual "m" shares only half of its genome with its offspring. Suppose individuals "m" and "f" produce a second offspring (offspring-2), whose genome is determined in exactly the same manner. There is a coin-flip 50% probability that offspring-2 will inherit the same copy of A from "m" as offspring-1 did (i.e. A<sub>m2</sub>). This also applies to gene B and so on through the alphabet. If a coin-flip "heads" means that gene X is the same in offspring-1 as it is in offspring-2, then in 26 flips of the coin approximately half are going to be "heads" and the rest "tails", i.e. half the genes inherited from parent "m" will be the same in the two offspring. The same will happen to the genes inherited from parent "f". Thus of the 52 genes inherited from the two parents, on average, 13 +  13 =  26 (or half) will be identical in the two sibs. Thus sibs are genetically as similar to one another as a parent is to an offspring.<sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-maynardsmith_8-0" class="reference"><a href="#cite_note-maynardsmith-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> From a evolutionary genetic point of view it is therefore as advantageous to help with the upbringing of full sibs as it is to produce and raise one's own offspring.</span> </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Cooperation_(evolution)&action=edit&section=17" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239543626"><div class="reflist reflist-columns references-column-width" style="column-width: 30em;"> <ol class="references"> <li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite id="CITEREFGardnerGriffinWest2009" class="citation book cs1">Gardner, Andy; Griffin, Ashleigh; West, Stuart (December 2009). <i>Theory of Cooperation</i>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1002%2F9780470015902.a0021910">10.1002/9780470015902.a0021910</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0470016176" title="Special:BookSources/978-0470016176"><bdi>978-0470016176</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Theory+of+Cooperation&rft.date=2009-12&rft_id=info%3Adoi%2F10.1002%2F9780470015902.a0021910&rft.isbn=978-0470016176&rft.aulast=Gardner&rft.aufirst=Andy&rft.au=Griffin%2C+Ashleigh&rft.au=West%2C+Stuart&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span> <span class="cs1-visible-error citation-comment"><code class="cs1-code">{{<a href="/wiki/Template:Cite_book" title="Template:Cite book">cite book</a>}}</code>: </span><span class="cs1-visible-error citation-comment"><code class="cs1-code">|journal=</code> ignored (<a href="/wiki/Help:CS1_errors#periodical_ignored" title="Help:CS1 errors">help</a>)</span></span> </li> <li id="cite_note-Clutton-Brock_2009_51–57-2"><span class="mw-cite-backlink">^ <a href="#cite_ref-Clutton-Brock_2009_51–57_2-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Clutton-Brock_2009_51–57_2-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-Clutton-Brock_2009_51–57_2-2"><sup><i><b>c</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFClutton-Brock2009" class="citation journal cs1">Clutton-Brock, T (5 November 2009). "Cooperation between non-kin in animal societies". <i>Nature</i>. <b>462</b> (7269): 51–57. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2009Natur.462...51C">2009Natur.462...51C</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1038%2Fnature08366">10.1038/nature08366</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/19890322">19890322</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:205218102">205218102</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Nature&rft.atitle=Cooperation+between+non-kin+in+animal+societies&rft.volume=462&rft.issue=7269&rft.pages=51-57&rft.date=2009-11-05&rft_id=info%3Adoi%2F10.1038%2Fnature08366&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A205218102%23id-name%3DS2CID&rft_id=info%3Apmid%2F19890322&rft_id=info%3Abibcode%2F2009Natur.462...51C&rft.aulast=Clutton-Brock&rft.aufirst=T&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-Hamilton-3"><span class="mw-cite-backlink">^ <a href="#cite_ref-Hamilton_3-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Hamilton_3-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHamilton1964" class="citation journal cs1">Hamilton, W. D. (1964). "The genetical evolution of social behaviour. I". <i>Journal of Theoretical Biology</i>. <b>7</b> (1): 1–16. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1964JThBi...7....1H">1964JThBi...7....1H</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2F0022-5193%2864%2990038-4">10.1016/0022-5193(64)90038-4</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/5875341">5875341</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Theoretical+Biology&rft.atitle=The+genetical+evolution+of+social+behaviour.+I&rft.volume=7&rft.issue=1&rft.pages=1-16&rft.date=1964&rft_id=info%3Apmid%2F5875341&rft_id=info%3Adoi%2F10.1016%2F0022-5193%2864%2990038-4&rft_id=info%3Abibcode%2F1964JThBi...7....1H&rft.aulast=Hamilton&rft.aufirst=W.+D.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-Clutton-4"><span class="mw-cite-backlink">^ <a href="#cite_ref-Clutton_4-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Clutton_4-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-Clutton_4-2"><sup><i><b>c</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFClutton-Brock2002" class="citation journal cs1">Clutton-Brock, T. (2002). "Breeding together: Kin selection and mutualism in cooperative vertebrates". <i>Science</i>. <b>296</b> (5565): 69–72. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2002Sci...296...69C">2002Sci...296...69C</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1126%2Fscience.296.5565.69">10.1126/science.296.5565.69</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/11935014">11935014</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Science&rft.atitle=Breeding+together%3A+Kin+selection+and+mutualism+in+cooperative+vertebrates&rft.volume=296&rft.issue=5565&rft.pages=69-72&rft.date=2002&rft_id=info%3Apmid%2F11935014&rft_id=info%3Adoi%2F10.1126%2Fscience.296.5565.69&rft_id=info%3Abibcode%2F2002Sci...296...69C&rft.aulast=Clutton-Brock&rft.aufirst=T.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-5">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSherman1977" class="citation journal cs1">Sherman, P (23 September 1977). "Nepotism and the evolution of alarm calls". <i>Science</i>. <b>197</b> (4310): 1246–1253. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1977Sci...197.1246S">1977Sci...197.1246S</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1126%2Fscience.197.4310.1246">10.1126/science.197.4310.1246</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/17781971">17781971</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Science&rft.atitle=Nepotism+and+the+evolution+of+alarm+calls&rft.volume=197&rft.issue=4310&rft.pages=1246-1253&rft.date=1977-09-23&rft_id=info%3Apmid%2F17781971&rft_id=info%3Adoi%2F10.1126%2Fscience.197.4310.1246&rft_id=info%3Abibcode%2F1977Sci...197.1246S&rft.aulast=Sherman&rft.aufirst=P&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHamilton1964" class="citation journal cs1">Hamilton, W (1 July 1964). "The genetical evolution of social behaviour. II". <i>Journal of Theoretical Biology</i>. <b>7</b> (1): 17–52. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1964JThBi...7...17H">1964JThBi...7...17H</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2F0022-5193%2864%2990039-6">10.1016/0022-5193(64)90039-6</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/5875340">5875340</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Theoretical+Biology&rft.atitle=The+genetical+evolution+of+social+behaviour.+II&rft.volume=7&rft.issue=1&rft.pages=17-52&rft.date=1964-07-01&rft_id=info%3Apmid%2F5875340&rft_id=info%3Adoi%2F10.1016%2F0022-5193%2864%2990039-6&rft_id=info%3Abibcode%2F1964JThBi...7...17H&rft.aulast=Hamilton&rft.aufirst=W&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-7">^</a></b></span> <span class="reference-text">Grafen, A. (1984) Natural selection, kin selection and group selection. In Krebs, J. R. & Davies, N. B. (Eds.) <i>Behavioural Ecology. An Evolutionary Approach.</i> (pp. 70–71). Oxford: Blackwell Scientific Publications. <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0632009985" title="Special:BookSources/0632009985">0632009985</a></span> </li> <li id="cite_note-maynardsmith-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-maynardsmith_8-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMaynard_Smith1989" class="citation book cs1">Maynard Smith, J. (1989). "Evolution in structured populations". <i>Evolutionary Genetics</i>. Oxford: Oxford University Press. pp. 173–175. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0198542155" title="Special:BookSources/978-0198542155"><bdi>978-0198542155</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Evolution+in+structured+populations&rft.btitle=Evolutionary+Genetics&rft.place=Oxford&rft.pages=173-175&rft.pub=Oxford+University+Press&rft.date=1989&rft.isbn=978-0198542155&rft.aulast=Maynard+Smith&rft.aufirst=J.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-10">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBalshine-EarnNeatReidTaborsky1998" class="citation journal cs1">Balshine-Earn, S.; Neat, F.C.; Reid, H.; Taborsky, M. (1998). <a rel="nofollow" class="external text" href="https://doi.org/10.1093%2Fbeheco%2F9.5.432">"Paying to stay or paying to breed? Field evidence for direct benefits of helping behavior in a cooperatively breeding fish"</a>. <i>Behavioral Ecology</i>. <b>9</b> (5): 432–438. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1093%2Fbeheco%2F9.5.432">10.1093/beheco/9.5.432</a></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Behavioral+Ecology&rft.atitle=Paying+to+stay+or+paying+to+breed%3F+Field+evidence+for+direct+benefits+of+helping+behavior+in+a+cooperatively+breeding+fish&rft.volume=9&rft.issue=5&rft.pages=432-438&rft.date=1998&rft_id=info%3Adoi%2F10.1093%2Fbeheco%2F9.5.432&rft.aulast=Balshine-Earn&rft.aufirst=S.&rft.au=Neat%2C+F.C.&rft.au=Reid%2C+H.&rft.au=Taborsky%2C+M.&rft_id=https%3A%2F%2Fdoi.org%2F10.1093%252Fbeheco%252F9.5.432&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-11">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSparkmanAdamsSteuryWaits2011" class="citation journal cs1">Sparkman, A. M.; Adams, J. R.; Steury, T. D.; Waits, L. P.; Murray, D. L. (2011). <a rel="nofollow" class="external text" href="https://doi.org/10.1093%2Fbeheco%2Farq194">"Direct fitness benefits of delayed dispersal in the cooperatively breeding red wolf (Canis rufus)"</a>. <i>Behavioral Ecology</i>. <b>22</b> (1): 199–205. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1093%2Fbeheco%2Farq194">10.1093/beheco/arq194</a></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Behavioral+Ecology&rft.atitle=Direct+fitness+benefits+of+delayed+dispersal+in+the+cooperatively+breeding+red+wolf+%28Canis+rufus%29&rft.volume=22&rft.issue=1&rft.pages=199-205&rft.date=2011&rft_id=info%3Adoi%2F10.1093%2Fbeheco%2Farq194&rft.aulast=Sparkman&rft.aufirst=A.+M.&rft.au=Adams%2C+J.+R.&rft.au=Steury%2C+T.+D.&rft.au=Waits%2C+L.+P.&rft.au=Murray%2C+D.+L.&rft_id=https%3A%2F%2Fdoi.org%2F10.1093%252Fbeheco%252Farq194&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-Griffin-12"><span class="mw-cite-backlink">^ <a href="#cite_ref-Griffin_12-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Griffin_12-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGriffinWest2003" class="citation journal cs1">Griffin, A. S.; West, S. A. (2003). "Kin Discrimination and the Benefit of Helping in Cooperatively Breeding Vertebrates". <i>Science</i>. <b>302</b> (5645): 634–636. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2003Sci...302..634G">2003Sci...302..634G</a>. <a href="/wiki/CiteSeerX_(identifier)" class="mw-redirect" title="CiteSeerX (identifier)">CiteSeerX</a> <span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.561.819">10.1.1.561.819</a></span>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1126%2Fscience.1089402">10.1126/science.1089402</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/14576431">14576431</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:8338275">8338275</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Science&rft.atitle=Kin+Discrimination+and+the+Benefit+of+Helping+in+Cooperatively+Breeding+Vertebrates&rft.volume=302&rft.issue=5645&rft.pages=634-636&rft.date=2003&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A8338275%23id-name%3DS2CID&rft_id=info%3Abibcode%2F2003Sci...302..634G&rft_id=https%3A%2F%2Fciteseerx.ist.psu.edu%2Fviewdoc%2Fsummary%3Fdoi%3D10.1.1.561.819%23id-name%3DCiteSeerX&rft_id=info%3Apmid%2F14576431&rft_id=info%3Adoi%2F10.1126%2Fscience.1089402&rft.aulast=Griffin&rft.aufirst=A.+S.&rft.au=West%2C+S.+A.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-13"><span class="mw-cite-backlink"><b><a href="#cite_ref-13">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBiernaskie2011" class="citation journal cs1">Biernaskie, J. M. (2011). <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3107641">"Evidence for competition and cooperation among climbing plants"</a>. <i>Proceedings of the Royal Society B: Biological Sciences</i>. <b>278</b> (1714): 1989–96. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1098%2Frspb.2010.1771">10.1098/rspb.2010.1771</a>. <a href="/wiki/PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3107641">3107641</a></span>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/21147795">21147795</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Proceedings+of+the+Royal+Society+B%3A+Biological+Sciences&rft.atitle=Evidence+for+competition+and+cooperation+among+climbing+plants&rft.volume=278&rft.issue=1714&rft.pages=1989-96&rft.date=2011&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC3107641%23id-name%3DPMC&rft_id=info%3Apmid%2F21147795&rft_id=info%3Adoi%2F10.1098%2Frspb.2010.1771&rft.aulast=Biernaskie&rft.aufirst=J.+M.&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC3107641&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-14"><span class="mw-cite-backlink"><b><a href="#cite_ref-14">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFClutton-BrockBrotherton,_P._N.Russell,_A._F.O'Riain,_M._J.2001" class="citation journal cs1">Clutton-Brock, T; Brotherton, P. N.; Russell, A. F.; O'Riain, M. J.; Gaynor, D.; Kansky, R.; Griffin, A.; Manser, M.; Sharpe, L.; McIlrath, G. M.; Small, T.; Moss, A.; Monfort, S. (2001). "Cooperation, control, and concession in meerkat groups". <i>Science</i>. <b>291</b> (5503): 478–481. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2001Sci...291..478C">2001Sci...291..478C</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1126%2Fscience.291.5503.478">10.1126/science.291.5503.478</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/11161200">11161200</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Science&rft.atitle=Cooperation%2C+control%2C+and+concession+in+meerkat+groups&rft.volume=291&rft.issue=5503&rft.pages=478-481&rft.date=2001&rft_id=info%3Apmid%2F11161200&rft_id=info%3Adoi%2F10.1126%2Fscience.291.5503.478&rft_id=info%3Abibcode%2F2001Sci...291..478C&rft.aulast=Clutton-Brock&rft.aufirst=T&rft.au=Brotherton%2C+P.+N.&rft.au=Russell%2C+A.+F.&rft.au=O%27Riain%2C+M.+J.&rft.au=Gaynor%2C+D.&rft.au=Kansky%2C+R.&rft.au=Griffin%2C+A.&rft.au=Manser%2C+M.&rft.au=Sharpe%2C+L.&rft.au=McIlrath%2C+G.+M.&rft.au=Small%2C+T.&rft.au=Moss%2C+A.&rft.au=Monfort%2C+S.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-15"><span class="mw-cite-backlink"><b><a href="#cite_ref-15">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFStrassmannSeppa,_P.Queller,_D._C.2000" class="citation journal cs1">Strassmann, J; Seppa, P.; Queller, D. C. (10 August 2000). "Absence of within-colony kin discrimination: foundresses of the social wasp, <i>Polistes carolina</i>, do not prefer their own larvae". <i>Naturwissenschaften</i>. <b>87</b> (6): 266–269. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2000NW.....87..266S">2000NW.....87..266S</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1007%2Fs001140050718">10.1007/s001140050718</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/10929290">10929290</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:12637238">12637238</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Naturwissenschaften&rft.atitle=Absence+of+within-colony+kin+discrimination%3A+foundresses+of+the+social+wasp%2C+Polistes+carolina%2C+do+not+prefer+their+own+larvae&rft.volume=87&rft.issue=6&rft.pages=266-269&rft.date=2000-08-10&rft_id=info%3Adoi%2F10.1007%2Fs001140050718&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A12637238%23id-name%3DS2CID&rft_id=info%3Apmid%2F10929290&rft_id=info%3Abibcode%2F2000NW.....87..266S&rft.aulast=Strassmann&rft.aufirst=J&rft.au=Seppa%2C+P.&rft.au=Queller%2C+D.+C.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-Behavioral_Ecology_2012-16"><span class="mw-cite-backlink">^ <a href="#cite_ref-Behavioral_Ecology_2012_16-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Behavioral_Ecology_2012_16-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-Behavioral_Ecology_2012_16-2"><sup><i><b>c</b></i></sup></a></span> <span class="reference-text"><i>An Introduction to Behavioral Ecology</i>. Davies, Nicholas B., John R. Krebs, and Stuart A. West. 2012.</span> </li> <li id="cite_note-17"><span class="mw-cite-backlink"><b><a href="#cite_ref-17">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHeinsohnPacker,_C.1995" class="citation journal cs1">Heinsohn, R; Packer, C. (1 September 1995). "Complex cooperative strategies in group-territorial African lions". <i>Science</i>. <b>269</b> (5228): 1260–1262. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1995Sci...269.1260H">1995Sci...269.1260H</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1126%2Fscience.7652573">10.1126/science.7652573</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/7652573">7652573</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:35849910">35849910</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Science&rft.atitle=Complex+cooperative+strategies+in+group-territorial+African+lions&rft.volume=269&rft.issue=5228&rft.pages=1260-1262&rft.date=1995-09-01&rft_id=info%3Adoi%2F10.1126%2Fscience.7652573&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A35849910%23id-name%3DS2CID&rft_id=info%3Apmid%2F7652573&rft_id=info%3Abibcode%2F1995Sci...269.1260H&rft.aulast=Heinsohn&rft.aufirst=R&rft.au=Packer%2C+C.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-18"><span class="mw-cite-backlink"><b><a href="#cite_ref-18">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFNorris2006" class="citation web cs1">Norris, Scott (15 March 2006). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20060316155136/http://news.nationalgeographic.com/news/2006/03/0315_060315_meerkats.html">"Murderous Meerkat Moms Contradict Caring Image, Study Finds"</a>. National Geographic News. Archived from <a rel="nofollow" class="external text" href="http://news.nationalgeographic.com/news/2006/03/0315_060315_meerkats.html">the original</a> on 16 March 2006<span class="reference-accessdate">. Retrieved <span class="nowrap">20 November</span> 2013</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Murderous+Meerkat+Moms+Contradict+Caring+Image%2C+Study+Finds&rft.pub=National+Geographic+News&rft.date=2006-03-15&rft.aulast=Norris&rft.aufirst=Scott&rft_id=http%3A%2F%2Fnews.nationalgeographic.com%2Fnews%2F2006%2F03%2F0315_060315_meerkats.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-19"><span class="mw-cite-backlink"><b><a href="#cite_ref-19">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGardnerAshleigh_S_GriffinStuart_A_West2009" class="citation journal cs1">Gardner, Andy; Ashleigh S Griffin; Stuart A West (2009). "Theory of Cooperation". <i>Encyclopedia of Life Sciences</i>: 1–8.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Encyclopedia+of+Life+Sciences&rft.atitle=Theory+of+Cooperation&rft.pages=1-8&rft.date=2009&rft.aulast=Gardner&rft.aufirst=Andy&rft.au=Ashleigh+S+Griffin&rft.au=Stuart+A+West&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-20"><span class="mw-cite-backlink"><b><a href="#cite_ref-20">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKummerliAndy_GardnerStuart_A._WestAshleigh_S._Griffin2009" class="citation journal cs1">Kummerli, Rolf; Andy Gardner; Stuart A. West; Ashleigh S. Griffin (April 2009). <a rel="nofollow" class="external text" href="https://doi.org/10.1111%2Fj.1558-5646.2008.00548.x">"Limited Dispersal, Budding Dispersal, and Cooperation: An Experimental Study"</a>. <i>Evolution</i>. <b>63</b> (4): 939–949. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1111%2Fj.1558-5646.2008.00548.x">10.1111/j.1558-5646.2008.00548.x</a></span>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/19154373">19154373</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:13882735">13882735</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Evolution&rft.atitle=Limited+Dispersal%2C+Budding+Dispersal%2C+and+Cooperation%3A+An+Experimental+Study&rft.volume=63&rft.issue=4&rft.pages=939-949&rft.date=2009-04&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A13882735%23id-name%3DS2CID&rft_id=info%3Apmid%2F19154373&rft_id=info%3Adoi%2F10.1111%2Fj.1558-5646.2008.00548.x&rft.aulast=Kummerli&rft.aufirst=Rolf&rft.au=Andy+Gardner&rft.au=Stuart+A.+West&rft.au=Ashleigh+S.+Griffin&rft_id=https%3A%2F%2Fdoi.org%2F10.1111%252Fj.1558-5646.2008.00548.x&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-21"><span class="mw-cite-backlink"><b><a href="#cite_ref-21">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGriffinWest,_S._A.Buckling,_A.2004" class="citation journal cs1">Griffin, A; West, S. A.; Buckling, A. (28 August 2004). "Cooperation and competition in pathogenic bacteria". <i>Nature</i>. <b>430</b> (7003): 1024–1027. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2004Natur.430.1024G">2004Natur.430.1024G</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1038%2Fnature02744">10.1038/nature02744</a>. <a href="/wiki/Hdl_(identifier)" class="mw-redirect" title="Hdl (identifier)">hdl</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://hdl.handle.net/1842%2F698">1842/698</a></span>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/15329720">15329720</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:4429250">4429250</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Nature&rft.atitle=Cooperation+and+competition+in+pathogenic+bacteria&rft.volume=430&rft.issue=7003&rft.pages=1024-1027&rft.date=2004-08-28&rft_id=info%3Ahdl%2F1842%2F698&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A4429250%23id-name%3DS2CID&rft_id=info%3Abibcode%2F2004Natur.430.1024G&rft_id=info%3Apmid%2F15329720&rft_id=info%3Adoi%2F10.1038%2Fnature02744&rft.aulast=Griffin&rft.aufirst=A&rft.au=West%2C+S.+A.&rft.au=Buckling%2C+A.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-22"><span class="mw-cite-backlink"><b><a href="#cite_ref-22">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSinervoAlexis_ChaineJean_ClobertRyan_Calsbeek2006" class="citation journal cs1">Sinervo, Barry; Alexis Chaine; Jean Clobert; Ryan Calsbeek; Lisa Hazard; Lesley Lancaster; Andrew G. McAdam; Suzanne Alonzo; Gwynne Corrigan; Michael E. Hochberg (1 May 2006). <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1564281">"Self-recognition, color signals, and cycles of greenbeard mutualism and altruism"</a>. <i>Proceedings of the National Academy of Sciences of the United States of America</i>. <b>103</b> (19): 7372–7377. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2006PNAS..103.7372S">2006PNAS..103.7372S</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1073%2Fpnas.0510260103">10.1073/pnas.0510260103</a></span>. <a href="/wiki/PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1564281">1564281</a></span>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/16651531">16651531</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Proceedings+of+the+National+Academy+of+Sciences+of+the+United+States+of+America&rft.atitle=Self-recognition%2C+color+signals%2C+and+cycles+of+greenbeard+mutualism+and+altruism&rft.volume=103&rft.issue=19&rft.pages=7372-7377&rft.date=2006-05-01&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC1564281%23id-name%3DPMC&rft_id=info%3Apmid%2F16651531&rft_id=info%3Adoi%2F10.1073%2Fpnas.0510260103&rft_id=info%3Abibcode%2F2006PNAS..103.7372S&rft.aulast=Sinervo&rft.aufirst=Barry&rft.au=Alexis+Chaine&rft.au=Jean+Clobert&rft.au=Ryan+Calsbeek&rft.au=Lisa+Hazard&rft.au=Lesley+Lancaster&rft.au=Andrew+G.+McAdam&rft.au=Suzanne+Alonzo&rft.au=Gwynne+Corrigan&rft.au=Michael+E.+Hochberg&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC1564281&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-Noe_&_Hammerstein,_1994-23"><span class="mw-cite-backlink"><b><a href="#cite_ref-Noe_&_Hammerstein,_1994_23-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFNoeHammerstein1994" class="citation journal cs1">Noe, R.; Hammerstein, P. (1994). "Biological markets: supply and demand determine the effect of partner choice in cooperation, mutualism and mating". <i>Behavioral Ecology and Sociobiology</i>. <b>35</b> (1): 1–11. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1994BEcoS..35....1N">1994BEcoS..35....1N</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1007%2FBF00167053">10.1007/BF00167053</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:37085820">37085820</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Behavioral+Ecology+and+Sociobiology&rft.atitle=Biological+markets%3A+supply+and+demand+determine+the+effect+of+partner+choice+in+cooperation%2C+mutualism+and+mating&rft.volume=35&rft.issue=1&rft.pages=1-11&rft.date=1994&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A37085820%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1007%2FBF00167053&rft_id=info%3Abibcode%2F1994BEcoS..35....1N&rft.aulast=Noe&rft.aufirst=R.&rft.au=Hammerstein%2C+P.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-Advances_in_Agronomy-24"><span class="mw-cite-backlink"><b><a href="#cite_ref-Advances_in_Agronomy_24-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFZhangSmith2002" class="citation book cs1">Zhang, F; Smith, D. L (2002). <i>Interorganismal signaling in suboptimum environments: The legume-rhizobia symbiosis</i>. Vol. 76. pp. 125–161. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2FS0065-2113%2802%2976004-5">10.1016/S0065-2113(02)76004-5</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9780120007943" title="Special:BookSources/9780120007943"><bdi>9780120007943</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Interorganismal+signaling+in+suboptimum+environments%3A+The+legume-rhizobia+symbiosis&rft.pages=125-161&rft.date=2002&rft_id=info%3Adoi%2F10.1016%2FS0065-2113%2802%2976004-5&rft.isbn=9780120007943&rft.aulast=Zhang&rft.aufirst=F&rft.au=Smith%2C+D.+L&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span> <span class="cs1-visible-error citation-comment"><code class="cs1-code">{{<a href="/wiki/Template:Cite_book" title="Template:Cite book">cite book</a>}}</code>: </span><span class="cs1-visible-error citation-comment"><code class="cs1-code">|journal=</code> ignored (<a href="/wiki/Help:CS1_errors#periodical_ignored" title="Help:CS1 errors">help</a>)</span></span> </li> <li id="cite_note-Lichens-25"><span class="mw-cite-backlink"><b><a href="#cite_ref-Lichens_25-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLutzoniPagelReeb2001" class="citation journal cs1">Lutzoni, François; Pagel, Mark; Reeb, Valérie (2001). "Major fungal lineages are derived from lichen symbiotic ancestors". <i>Nature</i>. <b>411</b> (6840): 937–940. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2001Natur.411..937L">2001Natur.411..937L</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1038%2F35082053">10.1038/35082053</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/11418855">11418855</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:4414913">4414913</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Nature&rft.atitle=Major+fungal+lineages+are+derived+from+lichen+symbiotic+ancestors&rft.volume=411&rft.issue=6840&rft.pages=937-940&rft.date=2001&rft_id=info%3Adoi%2F10.1038%2F35082053&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A4414913%23id-name%3DS2CID&rft_id=info%3Apmid%2F11418855&rft_id=info%3Abibcode%2F2001Natur.411..937L&rft.aulast=Lutzoni&rft.aufirst=Fran%C3%A7ois&rft.au=Pagel%2C+Mark&rft.au=Reeb%2C+Val%C3%A9rie&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-Elephant_Dung-26"><span class="mw-cite-backlink"><b><a href="#cite_ref-Elephant_Dung_26-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFConnor2010" class="citation journal cs1">Connor, R. C. (2010). <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2936175">"Cooperation beyond the dyad: on simple models and a complex society"</a>. <i>Philosophical Transactions of the Royal Society B: Biological Sciences</i>. <b>365</b> (1553): 2687–2697. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1098%2Frstb.2010.0150">10.1098/rstb.2010.0150</a>. <a href="/wiki/PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2936175">2936175</a></span>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/20679112">20679112</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Philosophical+Transactions+of+the+Royal+Society+B%3A+Biological+Sciences&rft.atitle=Cooperation+beyond+the+dyad%3A+on+simple+models+and+a+complex+society&rft.volume=365&rft.issue=1553&rft.pages=2687-2697&rft.date=2010&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC2936175%23id-name%3DPMC&rft_id=info%3Apmid%2F20679112&rft_id=info%3Adoi%2F10.1098%2Frstb.2010.0150&rft.aulast=Connor&rft.aufirst=R.+C.&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC2936175&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-Cooperation_Through_Image_Scoring-27"><span class="mw-cite-backlink"><b><a href="#cite_ref-Cooperation_Through_Image_Scoring_27-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWedekind2000" class="citation journal cs1">Wedekind, C. (2000). "Cooperation Through Image Scoring in Humans". <i>Science</i>. <b>288</b> (5467): 850–852. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2000Sci...288..850W">2000Sci...288..850W</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1126%2Fscience.288.5467.850">10.1126/science.288.5467.850</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/10797005">10797005</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Science&rft.atitle=Cooperation+Through+Image+Scoring+in+Humans&rft.volume=288&rft.issue=5467&rft.pages=850-852&rft.date=2000&rft_id=info%3Apmid%2F10797005&rft_id=info%3Adoi%2F10.1126%2Fscience.288.5467.850&rft_id=info%3Abibcode%2F2000Sci...288..850W&rft.aulast=Wedekind&rft.aufirst=C.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-Behavioural_Processes-28"><span class="mw-cite-backlink"><b><a href="#cite_ref-Behavioural_Processes_28-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBergmüllerJohnstoneRussellBshary2007" class="citation journal cs1">Bergmüller, Ralph; Johnstone, Rufus A.; Russell, Andrew F.; Bshary, Redouan (2007). <a rel="nofollow" class="external text" href="http://doc.rero.ch/record/28332/files/Bergm_ller_Ralph_-_Integrating_cooperative_breeding_into_theoretical_20120124.pdf">"Integrating cooperative breeding into theoretical concepts of cooperation"</a> <span class="cs1-format">(PDF)</span>. <i>Behavioural Processes</i>. <b>76</b> (2): 61–72. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.beproc.2007.07.001">10.1016/j.beproc.2007.07.001</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/17703898">17703898</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:15044219">15044219</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Behavioural+Processes&rft.atitle=Integrating+cooperative+breeding+into+theoretical+concepts+of+cooperation&rft.volume=76&rft.issue=2&rft.pages=61-72&rft.date=2007&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A15044219%23id-name%3DS2CID&rft_id=info%3Apmid%2F17703898&rft_id=info%3Adoi%2F10.1016%2Fj.beproc.2007.07.001&rft.aulast=Bergm%C3%BCller&rft.aufirst=Ralph&rft.au=Johnstone%2C+Rufus+A.&rft.au=Russell%2C+Andrew+F.&rft.au=Bshary%2C+Redouan&rft_id=http%3A%2F%2Fdoc.rero.ch%2Frecord%2F28332%2Ffiles%2FBergm_ller_Ralph_-_Integrating_cooperative_breeding_into_theoretical_20120124.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-sigmund-29"><span class="mw-cite-backlink">^ <a href="#cite_ref-sigmund_29-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-sigmund_29-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-sigmund_29-2"><sup><i><b>c</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSigmund1993" class="citation book cs1">Sigmund, K. (1993). <i>Games of Life</i>. Oxford: Oxford University Press. pp. 180–206.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Games+of+Life.&rft.place=Oxford&rft.pages=180-206&rft.pub=Oxford+University+Press&rft.date=1993&rft.aulast=Sigmund&rft.aufirst=K.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-axelrod-30"><span class="mw-cite-backlink">^ <a href="#cite_ref-axelrod_30-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-axelrod_30-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAxelrodHamilton1981" class="citation journal cs1">Axelrod, R.; Hamilton, W.D. (1981). "The evolution of cooperation". <i>Science</i>. <b>211</b> (4489): 1390–1396. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1981Sci...211.1390A">1981Sci...211.1390A</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1126%2Fscience.7466396">10.1126/science.7466396</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/7466396">7466396</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Science&rft.atitle=The+evolution+of+cooperation&rft.volume=211&rft.issue=4489&rft.pages=1390-1396&rft.date=1981&rft_id=info%3Apmid%2F7466396&rft_id=info%3Adoi%2F10.1126%2Fscience.7466396&rft_id=info%3Abibcode%2F1981Sci...211.1390A&rft.aulast=Axelrod&rft.aufirst=R.&rft.au=Hamilton%2C+W.D.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-31"><span class="mw-cite-backlink"><b><a href="#cite_ref-31">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFTrivers1971" class="citation journal cs1">Trivers, R.L. (1971). "The evolution of reciprocal altruism". <i>Quarterly Review of Biology</i>. <b>46</b>: 35–57. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F406755">10.1086/406755</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:19027999">19027999</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Quarterly+Review+of+Biology&rft.atitle=The+evolution+of+reciprocal+altruism&rft.volume=46&rft.pages=35-57&rft.date=1971&rft_id=info%3Adoi%2F10.1086%2F406755&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A19027999%23id-name%3DS2CID&rft.aulast=Trivers&rft.aufirst=R.L.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-32"><span class="mw-cite-backlink"><b><a href="#cite_ref-32">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMaynard_Smith1989" class="citation book cs1">Maynard Smith, J. (1989). "Evolution in structured populations". <i>Evolutionary Genetics</i>. Oxford: Oxford University Press. pp. 168–169, 181–183. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0198542155" title="Special:BookSources/978-0198542155"><bdi>978-0198542155</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Evolution+in+structured+populations&rft.btitle=Evolutionary+Genetics&rft.place=Oxford&rft.pages=168-169%2C+181-183&rft.pub=Oxford+University+Press&rft.date=1989&rft.isbn=978-0198542155&rft.aulast=Maynard+Smith&rft.aufirst=J.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-33"><span class="mw-cite-backlink"><b><a href="#cite_ref-33">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGodfray,_H._C._J.1992" class="citation journal cs1">Godfray, H. C. J. (1992). "The evolution of forgiveness". <i>Nature</i>. <b>355</b> (6357): 206–207. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1992Natur.355..206G">1992Natur.355..206G</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1038%2F355206a0">10.1038/355206a0</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:4335611">4335611</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Nature&rft.atitle=The+evolution+of+forgiveness&rft.volume=355&rft.issue=6357&rft.pages=206-207&rft.date=1992&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A4335611%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1038%2F355206a0&rft_id=info%3Abibcode%2F1992Natur.355..206G&rft.au=Godfray%2C+H.+C.+J.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-34"><span class="mw-cite-backlink"><b><a href="#cite_ref-34">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFNovakSigmund1993" class="citation journal cs1">Novak, M.; Sigmund, K. (1993). <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC46660">"Chaos and the evolution of cooperation"</a>. <i>Proceedings of the National Academy of Sciences of the United States of America</i>. <b>90</b> (11): 5091–5094. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1993PNAS...90.5091N">1993PNAS...90.5091N</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1073%2Fpnas.90.11.5091">10.1073/pnas.90.11.5091</a></span>. <a href="/wiki/PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC46660">46660</a></span>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/8506355">8506355</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Proceedings+of+the+National+Academy+of+Sciences+of+the+United+States+of+America&rft.atitle=Chaos+and+the+evolution+of+cooperation&rft.volume=90&rft.issue=11&rft.pages=5091-5094&rft.date=1993&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC46660%23id-name%3DPMC&rft_id=info%3Apmid%2F8506355&rft_id=info%3Adoi%2F10.1073%2Fpnas.90.11.5091&rft_id=info%3Abibcode%2F1993PNAS...90.5091N&rft.aulast=Novak&rft.aufirst=M.&rft.au=Sigmund%2C+K.&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC46660&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-koeslag1-35"><span class="mw-cite-backlink">^ <a href="#cite_ref-koeslag1_35-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-koeslag1_35-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKoeslag1997" class="citation journal cs1">Koeslag, J.H. (1997). "Sex, the Prisoner's Dilemma Game, and the evolutionary inevitability of cooperation". <i>Journal of Theoretical Biology</i>. <b>189</b> (1): 53–61. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1997JThBi.189...53K">1997JThBi.189...53K</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1006%2Fjtbi.1997.0496">10.1006/jtbi.1997.0496</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/9398503">9398503</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Theoretical+Biology&rft.atitle=Sex%2C+the+Prisoner%27s+Dilemma+Game%2C+and+the+evolutionary+inevitability+of+cooperation&rft.volume=189&rft.issue=1&rft.pages=53-61&rft.date=1997&rft_id=info%3Apmid%2F9398503&rft_id=info%3Adoi%2F10.1006%2Fjtbi.1997.0496&rft_id=info%3Abibcode%2F1997JThBi.189...53K&rft.aulast=Koeslag&rft.aufirst=J.H.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-36"><span class="mw-cite-backlink"><b><a href="#cite_ref-36">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFvan_den_Assemvan_DolderThaler2012" class="citation journal cs1">van den Assem; van Dolder; Thaler (2012). "<i>Split or Steal</i>? Cooperative Behavior when the Stakes are Large". <a href="/wiki/SSRN_(identifier)" class="mw-redirect" title="SSRN (identifier)">SSRN</a> <a rel="nofollow" class="external text" href="https://papers.ssrn.com/sol3/papers.cfm?abstract_id=1592456">1592456</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.atitle=Split+or+Steal%3F+Cooperative+Behavior+when+the+Stakes+are+Large&rft.date=2012&rft_id=https%3A%2F%2Fpapers.ssrn.com%2Fsol3%2Fpapers.cfm%3Fabstract_id%3D1592456%23id-name%3DSSRN&rft.au=van+den+Assem&rft.au=van+Dolder&rft.au=Thaler&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span> <span class="cs1-visible-error citation-comment"><code class="cs1-code">{{<a href="/wiki/Template:Cite_journal" title="Template:Cite journal">cite journal</a>}}</code>: </span><span class="cs1-visible-error citation-comment">Cite journal requires <code class="cs1-code">|journal=</code> (<a href="/wiki/Help:CS1_errors#missing_periodical" title="Help:CS1 errors">help</a>)</span></span> </li> <li id="cite_note-37"><span class="mw-cite-backlink"><b><a href="#cite_ref-37">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFZahavi1975" class="citation journal cs1">Zahavi, Amotz (1975). "Mate selection—a selection for a handicap". <i><a href="/wiki/Journal_of_Theoretical_Biology" title="Journal of Theoretical Biology">Journal of Theoretical Biology</a></i>. <b>53</b> (1): 205–214. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1975JThBi..53..205Z">1975JThBi..53..205Z</a>. <a href="/wiki/CiteSeerX_(identifier)" class="mw-redirect" title="CiteSeerX (identifier)">CiteSeerX</a> <span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.586.3819">10.1.1.586.3819</a></span>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2F0022-5193%2875%2990111-3">10.1016/0022-5193(75)90111-3</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/1195756">1195756</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Theoretical+Biology&rft.atitle=Mate+selection%E2%80%94a+selection+for+a+handicap&rft.volume=53&rft.issue=1&rft.pages=205-214&rft.date=1975&rft_id=https%3A%2F%2Fciteseerx.ist.psu.edu%2Fviewdoc%2Fsummary%3Fdoi%3D10.1.1.586.3819%23id-name%3DCiteSeerX&rft_id=info%3Apmid%2F1195756&rft_id=info%3Adoi%2F10.1016%2F0022-5193%2875%2990111-3&rft_id=info%3Abibcode%2F1975JThBi..53..205Z&rft.aulast=Zahavi&rft.aufirst=Amotz&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-zahavi-38"><span class="mw-cite-backlink">^ <a href="#cite_ref-zahavi_38-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-zahavi_38-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFZahavi1977" class="citation journal cs1">Zahavi, Amotz (1977). "The cost of honesty (Further remarks on the handicap principle)". <i>Journal of Theoretical Biology</i>. <b>67</b> (3): 603–605. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1977JThBi..67..603Z">1977JThBi..67..603Z</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2F0022-5193%2877%2990061-3">10.1016/0022-5193(77)90061-3</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/904334">904334</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Theoretical+Biology&rft.atitle=The+cost+of+honesty+%28Further+remarks+on+the+handicap+principle%29&rft.volume=67&rft.issue=3&rft.pages=603-605&rft.date=1977&rft_id=info%3Apmid%2F904334&rft_id=info%3Adoi%2F10.1016%2F0022-5193%2877%2990061-3&rft_id=info%3Abibcode%2F1977JThBi..67..603Z&rft.aulast=Zahavi&rft.aufirst=Amotz&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-39"><span class="mw-cite-backlink"><b><a href="#cite_ref-39">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFZahavi1997" class="citation book cs1">Zahavi, Amotz (1997). <span class="id-lock-registration" title="Free registration required"><a rel="nofollow" class="external text" href="https://archive.org/details/handicapprincipl0000zeha"><i>The handicap principle: a missing piece of Darwin's puzzle</i></a></span>. Oxford: Oxford University Press. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-19-510035-8" title="Special:BookSources/978-0-19-510035-8"><bdi>978-0-19-510035-8</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+handicap+principle%3A+a+missing+piece+of+Darwin%27s+puzzle&rft.place=Oxford&rft.pub=Oxford+University+Press&rft.date=1997&rft.isbn=978-0-19-510035-8&rft.aulast=Zahavi&rft.aufirst=Amotz&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fhandicapprincipl0000zeha&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-40"><span class="mw-cite-backlink"><b><a href="#cite_ref-40">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGrafen1990" class="citation journal cs1">Grafen, A. (1990). "Biological signals as handicaps". <i>Journal of Theoretical Biology</i>. <b>144</b> (4): 517–546. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1990JThBi.144..517G">1990JThBi.144..517G</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2FS0022-5193%2805%2980088-8">10.1016/S0022-5193(05)80088-8</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/2402153">2402153</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Theoretical+Biology&rft.atitle=Biological+signals+as+handicaps&rft.volume=144&rft.issue=4&rft.pages=517-546&rft.date=1990&rft_id=info%3Apmid%2F2402153&rft_id=info%3Adoi%2F10.1016%2FS0022-5193%2805%2980088-8&rft_id=info%3Abibcode%2F1990JThBi.144..517G&rft.aulast=Grafen&rft.aufirst=A.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-41"><span class="mw-cite-backlink"><b><a href="#cite_ref-41">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFJohnstoneGrafen1993" class="citation journal cs1">Johnstone, RA; Grafen, A (1993). "Dishonesty and the handicap principle". <i>Animal Behaviour</i>. <b>46</b> (4): 759–764. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1006%2Fanbe.1993.1253">10.1006/anbe.1993.1253</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:53191998">53191998</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Animal+Behaviour&rft.atitle=Dishonesty+and+the+handicap+principle&rft.volume=46&rft.issue=4&rft.pages=759-764&rft.date=1993&rft_id=info%3Adoi%2F10.1006%2Fanbe.1993.1253&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A53191998%23id-name%3DS2CID&rft.aulast=Johnstone&rft.aufirst=RA&rft.au=Grafen%2C+A&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-42"><span class="mw-cite-backlink"><b><a href="#cite_ref-42">^</a></b></span> <span class="reference-text">Hockey, P.A.R., Dean, W.R.J., Ryan, P.G. (2005) <i>Roberts Birds of Southern Africa</i>, p. 176, 193. Trustees of the John Voelcker Bird Book Fund, Cape Town.</span> </li> <li id="cite_note-fisher-43"><span class="mw-cite-backlink">^ <a href="#cite_ref-fisher_43-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-fisher_43-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text">Fisher R. (1930) <i>The Genetical Theory of Natural Selection</i>.</span> </li> <li id="cite_note-44"><span class="mw-cite-backlink"><b><a href="#cite_ref-44">^</a></b></span> <span class="reference-text">Symons, D. (1979) <i>The Evolution of Human Sexuality</i>. Oxford: Oxford University Press.</span> </li> <li id="cite_note-Langlois_&_Roggman,_1990-45"><span class="mw-cite-backlink"><b><a href="#cite_ref-Langlois_&_Roggman,_1990_45-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLangloisRoggman1990" class="citation journal cs1">Langlois, J. H.; Roggman, L. (1990). "Attractive faces are only average". <i>Psychological Science</i>. <b>1</b> (2): 115–121. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1111%2Fj.1467-9280.1990.tb00079.x">10.1111/j.1467-9280.1990.tb00079.x</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:18557871">18557871</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Psychological+Science&rft.atitle=Attractive+faces+are+only+average&rft.volume=1&rft.issue=2&rft.pages=115-121&rft.date=1990&rft_id=info%3Adoi%2F10.1111%2Fj.1467-9280.1990.tb00079.x&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A18557871%23id-name%3DS2CID&rft.aulast=Langlois&rft.aufirst=J.+H.&rft.au=Roggman%2C+L.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-Koeslag,_1990-46"><span class="mw-cite-backlink">^ <a href="#cite_ref-Koeslag,_1990_46-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Koeslag,_1990_46-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKoeslag1990" class="citation journal cs1">Koeslag, J. H. (1990). "Koinophilia groups sexual creatures into species, promotes stasis, and stabilizes social behaviour". <i>Journal of Theoretical Biology</i>. <b>144</b> (1): 15–35. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1990JThBi.144...15K">1990JThBi.144...15K</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fs0022-5193%2805%2980297-8">10.1016/s0022-5193(05)80297-8</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/2200930">2200930</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Theoretical+Biology&rft.atitle=Koinophilia+groups+sexual+creatures+into+species%2C+promotes+stasis%2C+and+stabilizes+social+behaviour&rft.volume=144&rft.issue=1&rft.pages=15-35&rft.date=1990&rft_id=info%3Apmid%2F2200930&rft_id=info%3Adoi%2F10.1016%2Fs0022-5193%2805%2980297-8&rft_id=info%3Abibcode%2F1990JThBi.144...15K&rft.aulast=Koeslag&rft.aufirst=J.+H.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-unnikrishnan-47"><span class="mw-cite-backlink"><b><a href="#cite_ref-unnikrishnan_47-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFUnnikrishnan,_M._K.Akhila,_H._S.2014" class="citation journal cs1">Unnikrishnan, M. K.; Akhila, H. S. (2014). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20160304000402/http://comments.sciencemag.org/content/10.1126/science.1253226">"The phenotypic differences between carrion and hooded crows across the hybridization zone in Europe are unlikely to be due to assortative mating. Comment on Poelstra, J.W. et al. (2014). The genomic landscape underlying phenotypic integrity in the face of gene flow in crows"</a>. <i>Science</i>. <b>344</b>: 1410–1414. Archived from <a rel="nofollow" class="external text" href="http://comments.sciencemag.org/content/10.1126/science.1253226">the original</a> on 4 March 2016<span class="reference-accessdate">. Retrieved <span class="nowrap">10 March</span> 2015</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Science&rft.atitle=The+phenotypic+differences+between+carrion+and+hooded+crows+across+the+hybridization+zone+in+Europe+are+unlikely+to+be+due+to+assortative+mating.+Comment+on+Poelstra%2C+J.W.+et+al.+%282014%29.+The+genomic+landscape+underlying+phenotypic+integrity+in+the+face+of+gene+flow+in+crows.&rft.volume=344&rft.pages=1410-1414&rft.date=2014&rft.au=Unnikrishnan%2C+M.+K.&rft.au=Akhila%2C+H.+S.&rft_id=http%3A%2F%2Fcomments.sciencemag.org%2Fcontent%2F10.1126%2Fscience.1253226&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-48"><span class="mw-cite-backlink"><b><a href="#cite_ref-48">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKoeslag2003" class="citation journal cs1">Koeslag, J.H. (2003). "Evolution of cooperation: cooperation defeats defection in the cornfield model". <i>Journal of Theoretical Biology</i>. <b>224</b> (3): 399–410. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2003JThBi.224..399K">2003JThBi.224..399K</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fs0022-5193%2803%2900188-7">10.1016/s0022-5193(03)00188-7</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/12941597">12941597</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Theoretical+Biology&rft.atitle=Evolution+of+cooperation%3A+cooperation+defeats+defection+in+the+cornfield+model&rft.volume=224&rft.issue=3&rft.pages=399-410&rft.date=2003&rft_id=info%3Apmid%2F12941597&rft_id=info%3Adoi%2F10.1016%2Fs0022-5193%2803%2900188-7&rft_id=info%3Abibcode%2F2003JThBi.224..399K&rft.aulast=Koeslag&rft.aufirst=J.H.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-49"><span class="mw-cite-backlink"><b><a href="#cite_ref-49">^</a></b></span> <span class="reference-text">Darwin, C. <i>The Origin of Species</i> Ch VIII (The Modern Library, 1859/1958)</span> </li> <li id="cite_note-50"><span class="mw-cite-backlink"><b><a href="#cite_ref-50">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDugatkin2002" class="citation journal cs1">Dugatkin, L. A. (2002). "Animal cooperation among unrelated individuals". <i>Naturwissenschaften</i>. <b>89</b> (12): 533–41. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2002NW.....89..533D">2002NW.....89..533D</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1007%2Fs00114-002-0379-y">10.1007/s00114-002-0379-y</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/12536274">12536274</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:11639874">11639874</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Naturwissenschaften&rft.atitle=Animal+cooperation+among+unrelated+individuals&rft.volume=89&rft.issue=12&rft.pages=533-41&rft.date=2002&rft_id=info%3Adoi%2F10.1007%2Fs00114-002-0379-y&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A11639874%23id-name%3DS2CID&rft_id=info%3Apmid%2F12536274&rft_id=info%3Abibcode%2F2002NW.....89..533D&rft.aulast=Dugatkin&rft.aufirst=L.+A.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-51"><span class="mw-cite-backlink"><b><a href="#cite_ref-51">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAlexander1974" class="citation journal cs1">Alexander, R. (1974). "The evolution of social behavior". <i>Annual Review of Ecology and Systematics</i>. <b>5</b> (1): 325–83. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1974AnRES...5..325A">1974AnRES...5..325A</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1146%2Fannurev.es.05.110174.001545">10.1146/annurev.es.05.110174.001545</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Annual+Review+of+Ecology+and+Systematics&rft.atitle=The+evolution+of+social+behavior&rft.volume=5&rft.issue=1&rft.pages=325-83&rft.date=1974&rft_id=info%3Adoi%2F10.1146%2Fannurev.es.05.110174.001545&rft_id=info%3Abibcode%2F1974AnRES...5..325A&rft.aulast=Alexander&rft.aufirst=R.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-52"><span class="mw-cite-backlink"><b><a href="#cite_ref-52">^</a></b></span> <span class="reference-text">Noë, R., van Hooff, J., and Hammerstein, P. <i>Economics in Nature: Social Dilemmas, Mate Choice and Biological Markets</i> Cambridge University Press (2001)</span> </li> <li id="cite_note-53"><span class="mw-cite-backlink"><b><a href="#cite_ref-53">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMesterton-GibbonsAdams2002" class="citation journal cs1">Mesterton-Gibbons, M.; Adams, E.S. (2002). "The Economics of Animal Cooperation". <i>Science</i>. <b>298</b> (5601): 2146–7. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1126%2Fscience.1080051">10.1126/science.1080051</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/12481126">12481126</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:146590101">146590101</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Science&rft.atitle=The+Economics+of+Animal+Cooperation&rft.volume=298&rft.issue=5601&rft.pages=2146-7&rft.date=2002&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A146590101%23id-name%3DS2CID&rft_id=info%3Apmid%2F12481126&rft_id=info%3Adoi%2F10.1126%2Fscience.1080051&rft.aulast=Mesterton-Gibbons&rft.aufirst=M.&rft.au=Adams%2C+E.S.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> <li id="cite_note-54"><span class="mw-cite-backlink"><b><a href="#cite_ref-54">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFIbrahim2022" class="citation journal cs1">Ibrahim, Ahmed (2022). <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9449918">"The conditional defector strategies can violate the most crucial supporting mechanisms of cooperation"</a>. <i>Scientific Reports</i>. <b>12</b> (1): 15157. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2022NatSR..1215157I">2022NatSR..1215157I</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1038%2Fs41598-022-18797-2">10.1038/s41598-022-18797-2</a>. <a href="/wiki/PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9449918">9449918</a></span>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/36071078">36071078</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Scientific+Reports&rft.atitle=The+conditional+defector+strategies+can+violate+the+most+crucial+supporting+mechanisms+of+cooperation&rft.volume=12&rft.issue=1&rft.pages=15157&rft.date=2022&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC9449918%23id-name%3DPMC&rft_id=info%3Apmid%2F36071078&rft_id=info%3Adoi%2F10.1038%2Fs41598-022-18797-2&rft_id=info%3Abibcode%2F2022NatSR..1215157I&rft.aulast=Ibrahim&rft.aufirst=Ahmed&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC9449918&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></span> </li> </ol></div> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFNowak2006" class="citation journal cs1">Nowak, MA (2006). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20110518021052/http://www.ped.fas.harvard.edu/people/faculty/publications_nowak/Nowak_Science06.pdf">"Five rules for the evolution of cooperation"</a> <span class="cs1-format">(PDF)</span>. <i>Science</i>. <b>314</b> (5805): 1560–1563. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2006Sci...314.1560N">2006Sci...314.1560N</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1126%2Fscience.1133755">10.1126/science.1133755</a>. <a href="/wiki/PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3279745">3279745</a></span>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/17158317">17158317</a>. Archived from <a rel="nofollow" class="external text" href="http://www.ped.fas.harvard.edu/people/faculty/publications_nowak/Nowak_Science06.pdf">the original</a> <span class="cs1-format">(PDF)</span> on 18 May 2011.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Science&rft.atitle=Five+rules+for+the+evolution+of+cooperation&rft.volume=314&rft.issue=5805&rft.pages=1560-1563&rft.date=2006&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC3279745%23id-name%3DPMC&rft_id=info%3Apmid%2F17158317&rft_id=info%3Adoi%2F10.1126%2Fscience.1133755&rft_id=info%3Abibcode%2F2006Sci...314.1560N&rft.aulast=Nowak&rft.aufirst=MA&rft_id=http%3A%2F%2Fwww.ped.fas.harvard.edu%2Fpeople%2Ffaculty%2Fpublications_nowak%2FNowak_Science06.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBurtsevTurchin2006" class="citation journal cs1">Burtsev, Mikhail; Turchin, Peter (2006). "Evolution of cooperative strategies from first principles". <i>Nature</i>. <b>440</b> (7087): 1041–1044. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2006Natur.440.1041B">2006Natur.440.1041B</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1038%2Fnature04470">10.1038/nature04470</a>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/16625195">16625195</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:4340926">4340926</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Nature&rft.atitle=Evolution+of+cooperative+strategies+from+first+principles&rft.volume=440&rft.issue=7087&rft.pages=1041-1044&rft.date=2006&rft_id=info%3Adoi%2F10.1038%2Fnature04470&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A4340926%23id-name%3DS2CID&rft_id=info%3Apmid%2F16625195&rft_id=info%3Abibcode%2F2006Natur.440.1041B&rft.aulast=Burtsev&rft.aufirst=Mikhail&rft.au=Turchin%2C+Peter&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWestGriffinGardner2007" class="citation journal cs1">West, S. A.; Griffin, A. S.; Gardner, A. (2007). <a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.cub.2007.06.004">"Evolutionary explanations for cooperation"</a>. <i>Current Biology</i>. <b>17</b> (16): R661–R672. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2007CBio...17.R661W">2007CBio...17.R661W</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.cub.2007.06.004">10.1016/j.cub.2007.06.004</a></span>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/17714660">17714660</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:14869430">14869430</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Current+Biology&rft.atitle=Evolutionary+explanations+for+cooperation&rft.volume=17&rft.issue=16&rft.pages=R661-R672&rft.date=2007&rft_id=info%3Adoi%2F10.1016%2Fj.cub.2007.06.004&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A14869430%23id-name%3DS2CID&rft_id=info%3Apmid%2F17714660&rft_id=info%3Abibcode%2F2007CBio...17.R661W&rft.aulast=West&rft.aufirst=S.+A.&rft.au=Griffin%2C+A.+S.&rft.au=Gardner%2C+A.&rft_id=https%3A%2F%2Fdoi.org%2F10.1016%252Fj.cub.2007.06.004&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACooperation+%28evolution%29" class="Z3988"></span></li></ul> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><style data-mw-deduplicate="TemplateStyles:r1236075235">.mw-parser-output .navbox{box-sizing:border-box;border:1px solid #a2a9b1;width:100%;clear:both;font-size:88%;text-align:center;padding:1px;margin:1em auto 0}.mw-parser-output .navbox .navbox{margin-top:0}.mw-parser-output .navbox+.navbox,.mw-parser-output .navbox+.navbox-styles+.navbox{margin-top:-1px}.mw-parser-output .navbox-inner,.mw-parser-output .navbox-subgroup{width:100%}.mw-parser-output .navbox-group,.mw-parser-output .navbox-title,.mw-parser-output .navbox-abovebelow{padding:0.25em 1em;line-height:1.5em;text-align:center}.mw-parser-output .navbox-group{white-space:nowrap;text-align:right}.mw-parser-output .navbox,.mw-parser-output .navbox-subgroup{background-color:#fdfdfd}.mw-parser-output .navbox-list{line-height:1.5em;border-color:#fdfdfd}.mw-parser-output .navbox-list-with-group{text-align:left;border-left-width:2px;border-left-style:solid}.mw-parser-output tr+tr>.navbox-abovebelow,.mw-parser-output tr+tr>.navbox-group,.mw-parser-output tr+tr>.navbox-image,.mw-parser-output tr+tr>.navbox-list{border-top:2px solid #fdfdfd}.mw-parser-output .navbox-title{background-color:#ccf}.mw-parser-output .navbox-abovebelow,.mw-parser-output .navbox-group,.mw-parser-output .navbox-subgroup .navbox-title{background-color:#ddf}.mw-parser-output .navbox-subgroup .navbox-group,.mw-parser-output .navbox-subgroup .navbox-abovebelow{background-color:#e6e6ff}.mw-parser-output .navbox-even{background-color:#f7f7f7}.mw-parser-output .navbox-odd{background-color:transparent}.mw-parser-output .navbox .hlist td dl,.mw-parser-output .navbox .hlist td ol,.mw-parser-output .navbox .hlist td ul,.mw-parser-output .navbox td.hlist dl,.mw-parser-output .navbox td.hlist ol,.mw-parser-output .navbox td.hlist ul{padding:0.125em 0}.mw-parser-output .navbox .navbar{display:block;font-size:100%}.mw-parser-output .navbox-title .navbar{float:left;text-align:left;margin-right:0.5em}body.skin--responsive .mw-parser-output .navbox-image img{max-width:none!important}@media print{body.ns-0 .mw-parser-output .navbox{display:none!important}}</style></div><div role="navigation" class="navbox" aria-labelledby="Evolutionary_ecology" style="padding:3px"><table class="nowraplinks mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Evo_ecol" title="Template:Evo ecol"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Evo_ecol" title="Template talk:Evo ecol"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Evo_ecol" title="Special:EditPage/Template:Evo ecol"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Evolutionary_ecology" style="font-size:114%;margin:0 4em"><a href="/wiki/Evolutionary_ecology" title="Evolutionary ecology">Evolutionary ecology</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Patterns of evolution</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Coloration_evidence_for_natural_selection" title="Coloration evidence for natural selection">Coloration evidence for natural selection</a></li> <li><a href="/wiki/Convergent_evolution" title="Convergent evolution">Convergent evolution</a> <ul><li><a href="/wiki/List_of_examples_of_convergent_evolution" title="List of examples of convergent evolution">examples</a></li></ul></li> <li><a href="/wiki/Parallel_evolution" title="Parallel evolution">Parallel evolution</a></li> <li><a href="/wiki/Divergent_evolution" title="Divergent evolution">Divergent evolution</a></li> <li><a href="/wiki/Paradox_of_the_plankton" title="Paradox of the plankton">Paradox of the plankton</a></li> <li><a href="/wiki/Predator_satiation" title="Predator satiation">Predator satiation</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Signals</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Signalling_theory" title="Signalling theory">Signalling theory</a></li> <li><a href="/wiki/Anti-predator_adaptation" title="Anti-predator adaptation">Anti-predator adaptation</a> <ul><li><a href="/wiki/Alarm_signal" title="Alarm signal">Alarm signal</a></li> <li><a href="/wiki/Aposematism" title="Aposematism">Aposematism</a></li> <li><a href="/wiki/Apparent_death" title="Apparent death">Apparent death</a></li> <li><a href="/wiki/Deimatic_behaviour" title="Deimatic behaviour">Deimatic behaviour</a></li> <li><a href="/wiki/Distraction_display" title="Distraction display">Distraction display</a></li></ul></li> <li class="mw-empty-elt"></li> <li><a href="/wiki/Crypsis" title="Crypsis">Crypsis</a></li> <li><a href="/wiki/Camouflage" title="Camouflage">Camouflage</a></li> <li><a href="/wiki/Mimicry" title="Mimicry">Mimicry</a></li> <li><a href="/wiki/Unkenreflex" title="Unkenreflex">Unkenreflex</a></li></ul> </div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"></div><div role="navigation" class="navbox" aria-labelledby="Evolutionary_biology" style="padding:3px"><table class="nowraplinks hlist mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Evolution" title="Template:Evolution"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Evolution" title="Template talk:Evolution"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Evolution" title="Special:EditPage/Template:Evolution"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Evolutionary_biology" style="font-size:114%;margin:0 4em"><a href="/wiki/Evolutionary_biology" title="Evolutionary biology">Evolutionary biology</a></div></th></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <ul><li><a href="/wiki/Introduction_to_evolution" title="Introduction to evolution">Introduction</a></li> <li><a href="/wiki/Outline_of_evolution" title="Outline of evolution">Outline</a></li> <li><a href="/wiki/Timeline_of_the_evolutionary_history_of_life" title="Timeline of the evolutionary history of life">Timeline of evolution</a></li> <li><a href="/wiki/History_of_life" title="History of life">History of life</a></li> <li><a href="/wiki/Index_of_evolutionary_biology_articles" title="Index of evolutionary biology articles">Index</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Evolution" title="Evolution">Evolution</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Abiogenesis" title="Abiogenesis">Abiogenesis</a></li> <li><a href="/wiki/Adaptation" title="Adaptation">Adaptation</a></li> <li><a href="/wiki/Adaptive_radiation" title="Adaptive radiation">Adaptive radiation</a></li> <li><a href="/wiki/Altruism_(biology)" title="Altruism (biology)">Altruism</a> <ul><li><a href="/wiki/Cheating_(biology)" title="Cheating (biology)">Cheating</a></li> <li><a href="/wiki/Reciprocal_altruism" title="Reciprocal altruism">Reciprocal</a></li></ul></li> <li><a href="/wiki/Baldwin_effect" title="Baldwin effect">Baldwin effect</a></li> <li><a href="/wiki/Cladistics" title="Cladistics">Cladistics</a></li> <li><a href="/wiki/Coevolution" title="Coevolution">Coevolution</a> <ul><li><a href="/wiki/Mutualism_(biology)" title="Mutualism (biology)">Mutualism</a></li></ul></li> <li><a href="/wiki/Common_descent" title="Common descent">Common descent</a></li> <li><a href="/wiki/Convergent_evolution" title="Convergent evolution">Convergence</a></li> <li><a href="/wiki/Divergent_evolution" title="Divergent evolution">Divergence</a></li> <li><a href="/wiki/Earliest_known_life_forms" title="Earliest known life forms">Earliest known life forms</a></li> <li><a href="/wiki/Evidence_of_common_descent" title="Evidence of common descent">Evidence of evolution</a></li> <li><a href="/wiki/Evolutionary_arms_race" title="Evolutionary arms race">Evolutionary arms race</a></li> <li><a href="/wiki/Evolutionary_pressure" title="Evolutionary pressure">Evolutionary pressure</a></li> <li><a href="/wiki/Exaptation" title="Exaptation">Exaptation</a></li> <li><a href="/wiki/Extinction" title="Extinction">Extinction</a> <ul><li><a href="/wiki/Extinction_event" title="Extinction event">Event</a></li></ul></li> <li><a href="/wiki/Homology_(biology)" title="Homology (biology)">Homology</a></li> <li><a href="/wiki/Last_universal_common_ancestor" title="Last universal common ancestor">Last universal common ancestor</a></li> <li><a href="/wiki/Macroevolution" title="Macroevolution">Macroevolution</a></li> <li><a href="/wiki/Microevolution" title="Microevolution">Microevolution</a></li> <li><a href="/wiki/Evolutionary_mismatch" title="Evolutionary mismatch">Mismatch</a></li> <li><a href="/wiki/Nonadaptive_radiation" title="Nonadaptive radiation">Non-adaptive radiation</a></li> <li><a href="/wiki/Abiogenesis" title="Abiogenesis">Origin of life</a></li> <li><a href="/wiki/Panspermia" title="Panspermia">Panspermia</a></li> <li><a href="/wiki/Parallel_evolution" title="Parallel evolution">Parallel evolution</a></li> <li><a href="/wiki/Signalling_theory" title="Signalling theory">Signalling theory</a> <ul><li><a href="/wiki/Handicap_principle" title="Handicap principle">Handicap principle</a></li></ul></li> <li><a href="/wiki/Speciation" title="Speciation">Speciation</a> <ul><li><a href="/wiki/Species" title="Species">Species</a></li> <li><a href="/wiki/Species_complex" title="Species complex">Species complex</a></li></ul></li> <li><a href="/wiki/Evolutionary_taxonomy" title="Evolutionary taxonomy">Taxonomy</a></li> <li><a href="/wiki/Unit_of_selection" title="Unit of selection">Unit of selection</a> <ul><li><a href="/wiki/Gene-centered_view_of_evolution" title="Gene-centered view of evolution">Gene-centered view of evolution</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Population_genetics" title="Population genetics">Population<br />genetics</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Selective_breeding" title="Selective breeding">Artificial selection</a></li> <li><a href="/wiki/Biodiversity" title="Biodiversity">Biodiversity</a></li> <li><a href="/wiki/Evolutionarily_stable_strategy" title="Evolutionarily stable strategy">Evolutionarily stable strategy</a></li> <li><a href="/wiki/Fisher%27s_principle" title="Fisher's principle">Fisher's principle</a></li> <li><a href="/wiki/Fitness_(biology)" title="Fitness (biology)">Fitness</a> <ul><li><a href="/wiki/Inclusive_fitness" title="Inclusive fitness">Inclusive</a></li></ul></li> <li><a href="/wiki/Gene_flow" title="Gene flow">Gene flow</a></li> <li><a href="/wiki/Genetic_drift" title="Genetic drift">Genetic drift</a></li> <li><a href="/wiki/Kin_selection" title="Kin selection">Kin selection</a> <ul><li><a href="/wiki/Parental_investment" title="Parental investment">Parental investment</a></li> <li><a href="/wiki/Parent%E2%80%93offspring_conflict" title="Parent–offspring conflict">Parent–offspring conflict</a></li></ul></li> <li><a href="/wiki/Mutation" title="Mutation">Mutation</a></li> <li><a href="/wiki/Population" title="Population">Population</a></li> <li><a href="/wiki/Natural_selection" title="Natural selection">Natural selection</a></li> <li><a href="/wiki/Sexual_dimorphism" title="Sexual dimorphism">Sexual dimorphism</a></li> <li><a href="/wiki/Sexual_selection" title="Sexual selection">Sexual selection</a> <ul><li><a href="/wiki/Sexual_selection_in_flowering_plants" title="Sexual selection in flowering plants">Flowering plants</a></li> <li><a href="/wiki/Sexual_selection_in_fungi" title="Sexual selection in fungi">Fungi</a></li> <li><a href="/wiki/Mate_choice" title="Mate choice">Mate choice</a></li></ul></li> <li><a href="/wiki/Social_selection" title="Social selection">Social selection</a></li> <li><a href="/wiki/Trivers%E2%80%93Willard_hypothesis" title="Trivers–Willard hypothesis">Trivers–Willard hypothesis</a></li> <li><a href="/wiki/Genetic_variation" title="Genetic variation">Variation</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Development</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Canalisation_(genetics)" title="Canalisation (genetics)">Canalisation</a></li> <li><a href="/wiki/Evolutionary_developmental_biology" title="Evolutionary developmental biology">Evolutionary developmental biology</a></li> <li><a href="/wiki/Genetic_assimilation" title="Genetic assimilation">Genetic assimilation</a></li> <li><a href="/wiki/Inversion_(evolutionary_biology)" title="Inversion (evolutionary biology)">Inversion</a></li> <li><a href="/wiki/Modularity_(biology)" title="Modularity (biology)">Modularity</a></li> <li><a href="/wiki/Phenotypic_plasticity" title="Phenotypic plasticity">Phenotypic plasticity</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Of <a href="/wiki/Taxon" title="Taxon">taxa</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Evolution_of_bacteria" title="Evolution of bacteria">Bacteria</a></li> <li><a href="/wiki/Evolution_of_birds" title="Evolution of birds">Birds</a> <ul><li><a href="/wiki/Origin_of_birds" title="Origin of birds">origin</a></li></ul></li> <li><a href="/wiki/Evolution_of_brachiopods" title="Evolution of brachiopods">Brachiopods</a></li> <li><a href="/wiki/Evolution_of_molluscs" title="Evolution of molluscs">Molluscs</a> <ul><li><a href="/wiki/Evolution_of_cephalopods" title="Evolution of cephalopods">Cephalopods</a></li></ul></li> <li><a href="/wiki/Dinosaur#Evolutionary_history" title="Dinosaur">Dinosaurs</a></li> <li><a href="/wiki/Evolution_of_fish" title="Evolution of fish">Fish</a></li> <li><a href="/wiki/Evolution_of_fungi" title="Evolution of fungi">Fungi</a></li> <li><a href="/wiki/Evolution_of_insects" title="Evolution of insects">Insects</a> <ul><li><a href="/wiki/Evolution_of_butterflies" title="Evolution of butterflies">butterflies</a></li></ul></li> <li><a href="/wiki/History_of_life" title="History of life">Life</a></li> <li><a href="/wiki/Evolution_of_mammals" title="Evolution of mammals">Mammals</a> <ul><li><a href="/wiki/Cat_gap" title="Cat gap">cats</a></li> <li><a href="/wiki/Canidae#Evolution" title="Canidae">canids</a> <ul><li><a href="/wiki/Evolution_of_the_wolf" title="Evolution of the wolf">wolves</a></li> <li><a href="/wiki/Domestication_of_the_dog" title="Domestication of the dog">dogs</a></li></ul></li> <li><a href="/wiki/Hyena#Evolution" title="Hyena">hyenas</a></li> <li><a href="/wiki/Evolution_of_cetaceans" title="Evolution of cetaceans">dolphins and whales</a></li> <li><a href="/wiki/Evolution_of_the_horse" title="Evolution of the horse">horses</a></li> <li><a href="/wiki/Evolution_of_Macropodidae" title="Evolution of Macropodidae">Kangaroos</a></li> <li><a href="/wiki/Evolution_of_primates" title="Evolution of primates">primates</a> <ul><li><a href="/wiki/Human_evolution" title="Human evolution">humans</a></li> <li><a href="/wiki/Evolution_of_lemurs" title="Evolution of lemurs">lemurs</a></li></ul></li> <li><a href="/wiki/Evolution_of_sirenians" title="Evolution of sirenians">sea cows</a></li></ul></li> <li><a href="/wiki/Evolutionary_history_of_plants" title="Evolutionary history of plants">Plants</a> <ul><li><a href="/wiki/Pollinator-mediated_selection" title="Pollinator-mediated selection">pollinator-mediated</a></li></ul></li> <li><a href="/wiki/Evolution_of_reptiles" title="Evolution of reptiles">Reptiles</a></li> <li><a href="/wiki/Evolution_of_spiders" title="Evolution of spiders">Spiders</a></li> <li><a href="/wiki/Evolution_of_tetrapods" title="Evolution of tetrapods">Tetrapods</a></li> <li><a href="/wiki/Viral_evolution" title="Viral evolution">Viruses</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Of <a href="/wiki/Organ_(anatomy)" class="mw-redirect" title="Organ (anatomy)">organs</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Evolution_of_cells" title="Evolution of cells">Cell</a></li> <li><a href="/wiki/Models_of_DNA_evolution" title="Models of DNA evolution">DNA</a></li> <li><a href="/wiki/Evolution_of_flagella" title="Evolution of flagella">Flagella</a></li> <li><a href="/wiki/Eukaryote#Origin_of_eukaryotes" title="Eukaryote">Eukaryotes</a> <ul><li><a href="/wiki/Symbiogenesis" title="Symbiogenesis">symbiogenesis</a></li> <li><a href="/wiki/Chromosome#Eukaryotes" title="Chromosome">chromosome</a></li> <li><a href="/wiki/Endomembrane_system#Evolution" title="Endomembrane system">endomembrane system</a></li> <li><a href="/wiki/Mitochondrion#Origin_and_evolution" title="Mitochondrion">mitochondria</a></li> <li><a href="/wiki/Cell_nucleus#Evolution" title="Cell nucleus">nucleus</a></li> <li><a href="/wiki/Plastid#Origin" title="Plastid">plastids</a></li></ul></li> <li>In animals <ul><li><a href="/wiki/Evolution_of_the_eye" title="Evolution of the eye">eye</a></li> <li><a href="/wiki/Hair#Evolution" title="Hair">hair</a></li> <li><a href="/wiki/Evolution_of_mammalian_auditory_ossicles" title="Evolution of mammalian auditory ossicles">auditory ossicle</a></li> <li><a href="/wiki/Evolution_of_nervous_systems" title="Evolution of nervous systems">nervous system</a></li> <li><a href="/wiki/Evolution_of_the_brain" title="Evolution of the brain">brain</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Of <a href="/wiki/Biological_process" title="Biological process">processes</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Evolution_of_ageing" title="Evolution of ageing">Aging</a> <ul><li><a href="/wiki/Death#Evolution_of_aging_and_mortality" title="Death">Death</a></li> <li><a href="/wiki/Programmed_cell_death#Evolutionary_origin_of_mitochondrial_apoptosis" title="Programmed cell death">Programmed cell death</a></li></ul></li> <li><a href="/wiki/Origin_of_avian_flight" title="Origin of avian flight">Avian flight</a></li> <li><a href="/wiki/Evolution_of_biological_complexity" title="Evolution of biological complexity">Biological complexity</a></li> <li><a class="mw-selflink selflink">Cooperation</a></li> <li><a href="/wiki/Evolution_of_color_vision" title="Evolution of color vision">Color vision</a> <ul><li><a href="/wiki/Evolution_of_color_vision_in_primates" title="Evolution of color vision in primates">in primates</a></li></ul></li> <li><a href="/wiki/Evolution_of_emotion" title="Evolution of emotion">Emotion</a></li> <li><a href="/wiki/Empathy#Evolution_across_species" title="Empathy">Empathy</a></li> <li><a href="/wiki/Evolutionary_ethics" title="Evolutionary ethics">Ethics</a></li> <li><a href="/wiki/Evolution_of_eusociality" title="Evolution of eusociality">Eusociality</a></li> <li><a href="/wiki/Immune_system#Evolution_and_other_mechanisms" title="Immune system">Immune system</a></li> <li><a href="/wiki/Metabolism#Evolution" title="Metabolism">Metabolism</a></li> <li><a href="/wiki/Monogamy_in_animals" title="Monogamy in animals">Monogamy</a></li> <li><a href="/wiki/Evolution_of_morality" title="Evolution of morality">Morality</a></li> <li><a href="/wiki/Mosaic_evolution" title="Mosaic evolution">Mosaic evolution</a></li> <li><a href="/wiki/Multicellular_organism#Evolutionary_history" title="Multicellular organism">Multicellularity</a></li> <li><a href="/wiki/Evolution_of_sexual_reproduction" title="Evolution of sexual reproduction">Sexual reproduction</a> <ul><li><a href="/wiki/Anisogamy#Evolution" title="Anisogamy">Gamete differentiation/sexes</a></li> <li><a href="/wiki/Biological_life_cycle" title="Biological life cycle">Life cycles/nuclear phases</a></li> <li><a href="/wiki/Mating_type" title="Mating type">Mating types</a></li> <li><a href="/wiki/Origin_and_function_of_meiosis" title="Origin and function of meiosis">Meiosis</a></li> <li><a href="/wiki/Sex-determination_system#Evolution" title="Sex-determination system">Sex-determination</a></li></ul></li> <li><a href="/wiki/Evolution_of_snake_venom" title="Evolution of snake venom">Snake venom</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Tempo_and_Mode_in_Evolution" title="Tempo and Mode in Evolution">Tempo and modes</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Phyletic_gradualism" title="Phyletic gradualism">Gradualism</a>/<a href="/wiki/Punctuated_equilibrium" title="Punctuated equilibrium">Punctuated equilibrium</a>/<a href="/wiki/Saltation_(biology)" title="Saltation (biology)">Saltationism</a></li> <li><a href="/wiki/Point_mutation" title="Point mutation">Micromutation</a>/<a href="/wiki/Mutationism#Later_mutationist_theories" title="Mutationism">Macromutation</a></li> <li><a href="/wiki/Uniformitarianism" title="Uniformitarianism">Uniformitarianism</a>/<a href="/wiki/Catastrophism" title="Catastrophism">Catastrophism</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Speciation" title="Speciation">Speciation</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Allopatric_speciation" title="Allopatric speciation">Allopatric</a></li> <li><a href="/wiki/Anagenesis" title="Anagenesis">Anagenesis</a></li> <li><a href="/wiki/Catagenesis_(biology)" title="Catagenesis (biology)">Catagenesis</a></li> <li><a href="/wiki/Cladogenesis" title="Cladogenesis">Cladogenesis</a></li> <li><a href="/wiki/Cospeciation" title="Cospeciation">Cospeciation</a></li> <li><a href="/wiki/Ecological_speciation" title="Ecological speciation">Ecological</a></li> <li><a href="/wiki/Hybrid_speciation" title="Hybrid speciation">Hybrid</a></li> <li><a href="/wiki/Nonecological_speciation" title="Nonecological speciation">Non-ecological</a></li> <li><a href="/wiki/Parapatric_speciation" title="Parapatric speciation">Parapatric</a></li> <li><a href="/wiki/Peripatric_speciation" title="Peripatric speciation">Peripatric</a></li> <li><a href="/wiki/Reinforcement_(speciation)" title="Reinforcement (speciation)">Reinforcement</a></li> <li><a href="/wiki/Sympatric_speciation" title="Sympatric speciation">Sympatric</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/History_of_evolutionary_thought" title="History of evolutionary thought">History</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Evolutionary_ideas_of_the_Renaissance_and_Enlightenment" title="Evolutionary ideas of the Renaissance and Enlightenment">Renaissance and Enlightenment</a></li> <li><a href="/wiki/Transmutation_of_species" title="Transmutation of species">Transmutation of species</a></li> <li><a href="/wiki/David_Hume" title="David Hume">David Hume</a> <ul><li><i><a href="/wiki/Dialogues_Concerning_Natural_Religion" title="Dialogues Concerning Natural Religion">Dialogues Concerning Natural Religion</a></i></li></ul></li> <li><a href="/wiki/Charles_Darwin" title="Charles Darwin">Charles Darwin</a> <ul><li><i><a href="/wiki/On_the_Origin_of_Species" title="On the Origin of Species">On the Origin of Species</a></i></li></ul></li> <li><a href="/wiki/History_of_paleontology" title="History of paleontology">History of paleontology</a></li> <li><a href="/wiki/Transitional_fossil" title="Transitional fossil">Transitional fossil</a></li> <li><a href="/wiki/Blending_inheritance" title="Blending inheritance">Blending inheritance</a></li> <li><a href="/wiki/Mendelian_inheritance" title="Mendelian inheritance">Mendelian inheritance</a></li> <li><a href="/wiki/The_eclipse_of_Darwinism" title="The eclipse of Darwinism">The eclipse of Darwinism</a></li> <li><a href="/wiki/Neo-Darwinism" title="Neo-Darwinism">Neo-Darwinism</a></li> <li><a href="/wiki/Modern_synthesis_(20th_century)" title="Modern synthesis (20th century)">Modern synthesis</a></li> <li><a href="/wiki/History_of_molecular_evolution" title="History of molecular evolution">History of molecular evolution</a></li> <li><a href="/wiki/Extended_evolutionary_synthesis" title="Extended evolutionary synthesis">Extended evolutionary synthesis</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Philosophy</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Darwinism" title="Darwinism">Darwinism</a></li> <li><a href="/wiki/Alternatives_to_Darwinian_evolution" title="Alternatives to Darwinian evolution">Alternatives</a> <ul><li><a href="/wiki/Catastrophism" title="Catastrophism">Catastrophism</a></li> <li><a href="/wiki/Lamarckism" title="Lamarckism">Lamarckism</a></li> <li><a href="/wiki/Orthogenesis" title="Orthogenesis">Orthogenesis</a></li> <li><a href="/wiki/Mutationism" title="Mutationism">Mutationism</a></li> <li><a href="/wiki/Saltation_(biology)" title="Saltation (biology)">Saltationism</a></li> <li><a href="/wiki/Structuralism_(biology)" title="Structuralism (biology)">Structuralism</a> <ul><li><a href="/wiki/Spandrel_(biology)" title="Spandrel (biology)">Spandrel</a></li></ul></li> <li><a href="/wiki/Theistic_evolution" title="Theistic evolution">Theistic</a></li> <li><a href="/wiki/Vitalism" title="Vitalism">Vitalism</a></li></ul></li> <li><a href="/wiki/Teleology_in_biology" title="Teleology in biology">Teleology in biology</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Related</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Biogeography" title="Biogeography">Biogeography</a></li> <li><a href="/wiki/Ecological_genetics" title="Ecological genetics">Ecological genetics</a></li> <li><a href="/wiki/Evolutionary_medicine" title="Evolutionary medicine">Evolutionary medicine</a></li> <li><a href="/wiki/Group_selection" title="Group selection">Group selection</a> <ul><li><a href="/wiki/Cultural_evolution" title="Cultural evolution">Cultural evolution</a></li> <li><a href="/wiki/Cultural_group_selection" title="Cultural group selection">Cultural group selection</a></li> <li><a href="/wiki/Dual_inheritance_theory" title="Dual inheritance theory">Dual inheritance theory</a></li></ul></li> <li><a href="/wiki/Hologenome_theory_of_evolution" title="Hologenome theory of evolution">Hologenome theory of evolution</a></li> <li><a href="/wiki/Missing_heritability_problem" title="Missing heritability problem">Missing heritability problem</a></li> <li><a href="/wiki/Molecular_evolution" title="Molecular evolution">Molecular evolution</a></li> <li><a href="/wiki/Astrobiology" title="Astrobiology">Astrobiology</a></li> <li><a href="/wiki/Phylogenetics" title="Phylogenetics">Phylogenetics</a> <ul><li><a href="/wiki/Phylogenetic_tree" title="Phylogenetic tree">Tree</a></li></ul></li> <li><a href="/wiki/Polymorphism_(biology)" title="Polymorphism (biology)">Polymorphism</a></li> <li><a href="/wiki/Protocell" title="Protocell">Protocell</a></li> <li><a href="/wiki/Systematics" title="Systematics">Systematics</a></li> <li><a href="/wiki/Transgenerational_epigenetic_inheritance" title="Transgenerational epigenetic inheritance">Transgenerational epigenetic inheritance</a></li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <ul><li><span class="noviewer" typeof="mw:File"><span title="Category"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/23px-Symbol_category_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/31px-Symbol_category_class.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <a href="/wiki/Category:Evolutionary_biology" title="Category:Evolutionary biology">Category</a></li> <li><span class="noviewer" typeof="mw:File"><a href="/wiki/File:Symbol_portal_class.svg" class="mw-file-description" title="Portal"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/e/e2/Symbol_portal_class.svg/16px-Symbol_portal_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/e/e2/Symbol_portal_class.svg/23px-Symbol_portal_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/e/e2/Symbol_portal_class.svg/31px-Symbol_portal_class.svg.png 2x" data-file-width="180" data-file-height="185" /></a></span> <a href="/wiki/Portal:Evolutionary_biology" title="Portal:Evolutionary biology">Portal</a></li></ul> </div></td></tr></tbody></table></div>    </div><noscript><img src="https://login.wikimedia.org/wiki/Special:CentralAutoLogin/start?type=1x1" alt="" width="1" height="1" style="border: none; position: absolute;"></noscript> <div class="printfooter" data-nosnippet="">Retrieved from "<a dir="ltr" href="https://en.wikipedia.org/w/index.php?title=Cooperation_(evolution)&oldid=1258135617">https://en.wikipedia.org/w/index.php?title=Cooperation_(evolution)&oldid=1258135617</a>"</div></div> <div id="catlinks" class="catlinks" data-mw="interface"><div id="mw-normal-catlinks" class="mw-normal-catlinks"><a href="/wiki/Help:Category" title="Help:Category">Categories</a>: <ul><li><a href="/wiki/Category:Evolutionary_biology" title="Category:Evolutionary biology">Evolutionary biology</a></li><li><a href="/wiki/Category:Ethology" title="Category:Ethology">Ethology</a></li></ul></div><div id="mw-hidden-catlinks" class="mw-hidden-catlinks mw-hidden-cats-hidden">Hidden categories: <ul><li><a href="/wiki/Category:CS1_errors:_periodical_ignored" title="Category:CS1 errors: periodical ignored">CS1 errors: periodical ignored</a></li><li><a href="/wiki/Category:CS1_errors:_missing_periodical" title="Category:CS1 errors: missing periodical">CS1 errors: missing periodical</a></li><li><a href="/wiki/Category:Articles_with_short_description" title="Category:Articles with short description">Articles with short description</a></li><li><a href="/wiki/Category:Short_description_matches_Wikidata" title="Category:Short description matches Wikidata">Short description matches Wikidata</a></li><li><a href="/wiki/Category:Use_dmy_dates_from_January_2021" title="Category:Use dmy dates from January 2021">Use dmy dates from January 2021</a></li></ul></div></div> </div> </main> </div> <div class="mw-footer-container"> <footer id="footer" class="mw-footer" > <ul id="footer-info"> <li id="footer-info-lastmod"> This page was last edited on 18 November 2024, at 08:33<span class="anonymous-show"> (UTC)</span>.</li> <li id="footer-info-copyright">Text is available under the <a href="/wiki/Wikipedia:Text_of_the_Creative_Commons_Attribution-ShareAlike_4.0_International_License" title="Wikipedia:Text of the Creative Commons Attribution-ShareAlike 4.0 International License">Creative Commons Attribution-ShareAlike 4.0 License</a>; additional terms may apply. By using this site, you agree to the <a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Terms_of_Use" class="extiw" title="foundation:Special:MyLanguage/Policy:Terms of Use">Terms of Use</a> and <a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy" class="extiw" title="foundation:Special:MyLanguage/Policy:Privacy policy">Privacy Policy</a>. Wikipedia® is a registered trademark of the <a rel="nofollow" class="external text" href="https://wikimediafoundation.org/">Wikimedia Foundation, Inc.</a>, a non-profit organization.</li> </ul> <ul id="footer-places"> <li id="footer-places-privacy"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy">Privacy policy</a></li> <li id="footer-places-about"><a href="/wiki/Wikipedia:About">About Wikipedia</a></li> <li id="footer-places-disclaimers"><a href="/wiki/Wikipedia:General_disclaimer">Disclaimers</a></li> <li id="footer-places-contact"><a href="//en.wikipedia.org/wiki/Wikipedia:Contact_us">Contact Wikipedia</a></li> <li id="footer-places-wm-codeofconduct"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Universal_Code_of_Conduct">Code of Conduct</a></li> <li id="footer-places-developers"><a href="https://developer.wikimedia.org">Developers</a></li> <li id="footer-places-statslink"><a href="https://stats.wikimedia.org/#/en.wikipedia.org">Statistics</a></li> <li id="footer-places-cookiestatement"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Cookie_statement">Cookie statement</a></li> <li id="footer-places-mobileview"><a href="//en.m.wikipedia.org/w/index.php?title=Cooperation_(evolution)&mobileaction=toggle_view_mobile" class="noprint stopMobileRedirectToggle">Mobile view</a></li> </ul> <ul id="footer-icons" class="noprint"> <li id="footer-copyrightico"><a href="https://wikimediafoundation.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><img src="/static/images/footer/wikimedia-button.svg" width="84" height="29" alt="Wikimedia Foundation" loading="lazy"></a></li> <li id="footer-poweredbyico"><a href="https://www.mediawiki.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><img src="/w/resources/assets/poweredby_mediawiki.svg" alt="Powered by MediaWiki" width="88" height="31" loading="lazy"></a></li> </ul> </footer> </div> </div> </div> <div class="vector-settings" id="p-dock-bottom"> <ul></ul> </div><script>(RLQ=window.RLQ||[]).push(function(){mw.config.set({"wgHostname":"mw-web.codfw.main-6b7f745dd4-7vn4p","wgBackendResponseTime":188,"wgPageParseReport":{"limitreport":{"cputime":"0.986","walltime":"1.999","ppvisitednodes":{"value":3949,"limit":1000000},"postexpandincludesize":{"value":186692,"limit":2097152},"templateargumentsize":{"value":7923,"limit":2097152},"expansiondepth":{"value":16,"limit":100},"expensivefunctioncount":{"value":5,"limit":500},"unstrip-depth":{"value":1,"limit":20},"unstrip-size":{"value":245473,"limit":5000000},"entityaccesscount":{"value":0,"limit":400},"timingprofile":["100.00% 1778.282 1 -total"," 35.97% 639.713 2 Template:Reflist"," 35.66% 634.056 1 Template:Short_description"," 30.52% 542.764 2 Template:Pagetype"," 19.19% 341.181 42 Template:Cite_journal"," 12.34% 219.433 1 Template:Evolutionary_biology"," 11.98% 213.003 1 Template:Sidebar_with_collapsible_lists"," 9.28% 165.061 6 Template:Cite_book"," 3.58% 63.747 8 Template:Main_other"," 3.35% 59.510 1 Template:SDcat"]},"scribunto":{"limitreport-timeusage":{"value":"0.591","limit":"10.000"},"limitreport-memusage":{"value":7044463,"limit":52428800},"limitreport-logs":"table#1 {\n [\"size\"] = \"tiny\",\n}\n"},"cachereport":{"origin":"mw-api-ext.eqiad.main-6696b4cc84-rvljl","timestamp":"20241122144052","ttl":2592000,"transientcontent":false}}});});</script> <script type="application/ld+json">{"@context":"https:\/\/schema.org","@type":"Article","name":"Cooperation (evolution)","url":"https:\/\/en.wikipedia.org\/wiki\/Cooperation_(evolution)","sameAs":"http:\/\/www.wikidata.org\/entity\/Q3312519","mainEntity":"http:\/\/www.wikidata.org\/entity\/Q3312519","author":{"@type":"Organization","name":"Contributors to Wikimedia projects"},"publisher":{"@type":"Organization","name":"Wikimedia Foundation, Inc.","logo":{"@type":"ImageObject","url":"https:\/\/www.wikimedia.org\/static\/images\/wmf-hor-googpub.png"}},"datePublished":"2006-04-21T11:56:33Z","dateModified":"2024-11-18T08:33:36Z","headline":"evolutionary process where groups of organisms work or act together for common or mutual benefits"}</script> </body> </html>