Biodiversity I | Biology | Visionlearning

<!DOCTYPE html> <html lang="en" dir="ltr"> <head>  <meta http-equiv="X-UA-Compatible" content="ie=edge"> <meta charset="utf-8"> <base href="https://www.visionlearning.com"> <title>Biodiversity I | Biology | Visionlearning</title> <link rel="canonical" href="https://www.visionlearning.com/en/library/biology/2/biodiversity-i/276"> <meta name="description" content="Since the time of hunter-gatherers, human beings have been aware of how the wellbeing of plants and animals dictates our ability to survive. This module explores the strides we’ve made in understanding biological diversity (biodiversity) and how it impacts our ecosystems."> <meta name="keywords" content="ecosystem, ecosystems, environment, sustainability, patterning"> <meta name="viewport" content="width=device-width, initial-scale=1.0, shrink-to-fit=no"> <meta name="msvalidate.01" content="D8E20F39AD48052260032E56DE409970"> <script type="application/ld+json"> { "@context": "http://schema.org/", "@type": "Article", "mainEntityOfPage": { "@type": "WebPage", "@id": "https://visionlearning.com/en/library/biology/2/biodiversity-i/276" }, "name": "Biodiversity I", "headline": "Biodiversity I: Definitions and patterns of diversity", "author": { "@type": "Person", "name": "Devin Reese, PhD." }, "datePublished": "2022-06-21 16:31:19", "dateModified": "2017-02-12T08:30:00+05:00", "image": { "@type": "ImageObject", "url": "/img/library/moduleImages/featured_image_276-23061209063836.jpg", "width": 696, "height": 464 }, "publisher": { "@type": "Organization", "name": "Visionlearning, Inc.", "logo": { "@type": "ImageObject", "url": "http://visionlearning.com/images/logo.png", "width": 278, "height": 60 } }, "description": "Since the time of hunter-gatherers, human beings have been aware of how the wellbeing of plants and animals dictates our ability to survive. This module explores the strides we’ve made in understanding biological diversity (biodiversity) and how it impacts our ecosystems.", "keywords": "ecosystem, ecosystems, environment, sustainability, patterning", "inLanguage": { "@type": "Language", "name": "English", "alternateName": "en" }, "copyrightHolder": { "@type": "Organization", "name": "Visionlearning, Inc." }, "copyrightYear": "2022"} </script> <meta property="og:url" content="https://visionlearning.com/en/library/biology/2/biodiversity-i/276"> <meta property="og:title" content="Biodiversity I | Biology | Visionlearning" /> <meta property="og:type" content="website"> <meta property="og:site_name" content="Visionlearning"> <meta property="og:description" content="Since the time of hunter-gatherers, human beings have been aware of how the wellbeing of plants and animals dictates our ability to survive. 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href="/en/library/environmental-science/61/population-biology/287">Population Biology</a></li> </ul> </div> <button class="accordion__button" id="acc-button-earth-cycles" data-accordion="button" aria-controls="acc-panel-earth-cycles" aria-expanded="false"> <span class="accordion__button__label"> Earth Cycles </span> </button> <div class="accordion__panel" id="acc-panel-earth-cycles" data-accordion="panel" aria-labelledby="acc-button-earth-cycles" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/environmental-science/61/the-nitrogen-cycle/98">The Nitrogen Cycle</a></li> <li><a href="/en/library/environmental-science/61/the-carbon-cycle/95">The Carbon Cycle</a></li> <li><a href="/en/library/environmental-science/61/the-phosphorus-cycle/197">The Phosphorus Cycle</a></li> </ul> </div> <button class="accordion__button" id="acc-button-scientific-research" data-accordion="button" aria-controls="acc-panel-scientific-research" aria-expanded="false"> <span class="accordion__button__label"> Scientific Research </span> </button> <div class="accordion__panel" id="acc-panel-scientific-research" data-accordion="panel" aria-labelledby="acc-button-scientific-research" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/environmental-science/61/collaborative-research-in-the-arctic-towards-understanding-climate-change/183">Collaborative Research in the Arctic Towards Understanding Climate Change</a></li> <li><a href="/en/library/environmental-science/61/atmospheric-chemistry-research-that-changed-global-policy/211">Atmospheric Chemistry Research that Changed Global Policy</a></li> </ul> </div> </div> </div> <button class="accordion__button" id="acc-button-general-science" data-accordion="button" aria-controls="acc-panel-general-science" aria-expanded="false"> <span class="accordion__button__label"> General Science </span> </button> <div class="accordion__panel" id="acc-panel-general-science" data-accordion="panel" aria-labelledby="acc-button-general-science" role="region"> <div class="accordion accordion--secondary"> <button class="accordion__button" id="acc-button-methods" data-accordion="button" aria-controls="acc-panel-methods" aria-expanded="false"> <span class="accordion__button__label"> Methods </span> </button> <div class="accordion__panel" id="acc-panel-methods" data-accordion="panel" aria-labelledby="acc-button-methods" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/general-science/3/the-scientific-method/45">The Scientific Method</a></li> </ul> </div> <button class="accordion__button" id="acc-button-measurement" data-accordion="button" aria-controls="acc-panel-measurement" aria-expanded="false"> <span class="accordion__button__label"> Measurement </span> </button> <div class="accordion__panel" id="acc-panel-measurement" data-accordion="panel" aria-labelledby="acc-button-measurement" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/general-science/3/the-metric-system/47">The Metric System</a></li> </ul> </div> <button class="accordion__button" id="acc-button-physical-properties" data-accordion="button" aria-controls="acc-panel-physical-properties" aria-expanded="false"> <span class="accordion__button__label"> Physical Properties </span> </button> <div class="accordion__panel" id="acc-panel-physical-properties" data-accordion="panel" aria-labelledby="acc-button-physical-properties" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/general-science/3/temperature/48">Temperature</a></li> <li><a href="/en/library/general-science/3/density-and-buoyancy/37">Density and Buoyancy</a></li> </ul> </div> </div> </div> <button class="accordion__button" id="acc-button-math-in-science" data-accordion="button" aria-controls="acc-panel-math-in-science" aria-expanded="false"> <span class="accordion__button__label"> Math in Science </span> </button> <div class="accordion__panel" id="acc-panel-math-in-science" data-accordion="panel" aria-labelledby="acc-button-math-in-science" role="region"> <div class="accordion accordion--secondary"> <button class="accordion__button" id="acc-button-equations" data-accordion="button" aria-controls="acc-panel-equations" aria-expanded="false"> <span class="accordion__button__label"> Equations </span> </button> <div class="accordion__panel" id="acc-panel-equations" data-accordion="panel" aria-labelledby="acc-button-equations" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/math-in-science/62/unit-conversion/144">Unit Conversion</a></li> <li><a href="/en/library/math-in-science/62/linear-equations/194">Linear Equations</a></li> <li><a href="/en/library/math-in-science/62/exponential-equations-i/206">Exponential Equations I</a></li> <li><a href="/en/library/math-in-science/62/exponential-equations-ii/210">Exponential Equations II</a></li> <li><a href="/en/library/math-in-science/62/scientific-notation/250">Scientific Notation</a></li> <li><a href="/en/library/math-in-science/62/measurement/257">Measurement</a></li> </ul> </div> <button class="accordion__button" id="acc-button-statistics" data-accordion="button" aria-controls="acc-panel-statistics" aria-expanded="false"> <span class="accordion__button__label"> Statistics </span> </button> <div class="accordion__panel" id="acc-panel-statistics" data-accordion="panel" aria-labelledby="acc-button-statistics" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/math-in-science/62/introduction-to-descriptive-statistics/218">Introduction to Descriptive Statistics</a></li> <li><a href="/en/library/math-in-science/62/introduction-to-inferential-statistics/224">Introduction to Inferential Statistics</a></li> <li><a href="/en/library/math-in-science/62/statistical-techniques/239">Statistical Techniques</a></li> </ul> </div> <button class="accordion__button" id="acc-button-trigonometric-functions" data-accordion="button" aria-controls="acc-panel-trigonometric-functions" aria-expanded="false"> <span class="accordion__button__label"> Trigonometric Functions </span> </button> <div class="accordion__panel" id="acc-panel-trigonometric-functions" data-accordion="panel" aria-labelledby="acc-button-trigonometric-functions" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/math-in-science/62/wave-mathematics/131">Wave Mathematics</a></li> </ul> </div> </div> </div> <button class="accordion__button" id="acc-button-physics" data-accordion="button" aria-controls="acc-panel-physics" aria-expanded="false"> <span class="accordion__button__label"> Physics </span> </button> <div class="accordion__panel" id="acc-panel-physics" data-accordion="panel" aria-labelledby="acc-button-physics" role="region"> <div class="accordion accordion--secondary"> <button class="accordion__button" id="acc-button-light-and-optics" data-accordion="button" aria-controls="acc-panel-light-and-optics" aria-expanded="false"> <span class="accordion__button__label"> Light and Optics </span> </button> <div class="accordion__panel" id="acc-panel-light-and-optics" data-accordion="panel" aria-labelledby="acc-button-light-and-optics" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/physics/24/the-nature-of-light/132">The Nature of Light</a></li> <li><a href="/en/library/physics/24/electromagnetism-and-light/138">Electromagnetism and Light</a></li> </ul> </div> <button class="accordion__button" id="acc-button-mechanics" data-accordion="button" aria-controls="acc-panel-mechanics" aria-expanded="false"> <span class="accordion__button__label"> Mechanics </span> </button> <div class="accordion__panel" id="acc-panel-mechanics" data-accordion="panel" aria-labelledby="acc-button-mechanics" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/physics/24/defining-energy/199">Defining Energy</a></li> <li><a href="/en/library/physics/24/waves-and-wave-motion/102">Waves and Wave Motion</a></li> <li><a href="/en/library/physics/24/gravity/118">Gravity</a></li> <li><a href="/en/library/physics/24/thermodynamics-i/200">Thermodynamics I</a></li> </ul> </div> </div> </div> <button class="accordion__button" id="acc-button-process-of-science" data-accordion="button" aria-controls="acc-panel-process-of-science" aria-expanded="false"> <span class="accordion__button__label"> Process of Science </span> </button> <div class="accordion__panel" id="acc-panel-process-of-science" data-accordion="panel" aria-labelledby="acc-button-process-of-science" role="region"> <div class="accordion accordion--secondary"> <button class="accordion__button" id="acc-button-introduction" data-accordion="button" aria-controls="acc-panel-introduction" aria-expanded="false"> <span class="accordion__button__label"> Introduction </span> </button> <div class="accordion__panel" id="acc-panel-introduction" data-accordion="panel" aria-labelledby="acc-button-introduction" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/process-of-science/49/the-process-of-science/176">The Process of Science</a></li> </ul> </div> <button class="accordion__button" id="acc-button-the-culture-of-science" data-accordion="button" aria-controls="acc-panel-the-culture-of-science" aria-expanded="false"> <span class="accordion__button__label"> The Culture of Science </span> </button> <div class="accordion__panel" id="acc-panel-the-culture-of-science" data-accordion="panel" aria-labelledby="acc-button-the-culture-of-science" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/process-of-science/49/the-nature-of-scientific-knowledge/185">The Nature of Scientific Knowledge</a></li> <li><a href="/en/library/process-of-science/49/scientists-and-the-scientific-community/172">Scientists and the Scientific Community</a></li> <li><a href="/en/library/process-of-science/49/scientific-ethics/161">Scientific Ethics</a></li> <li><a href="/en/library/process-of-science/49/scientific-institutions-and-societies/162">Scientific Institutions and Societies</a></li> </ul> </div> <button class="accordion__button" id="acc-button-ideas-in-science" data-accordion="button" aria-controls="acc-panel-ideas-in-science" aria-expanded="false"> <span class="accordion__button__label"> Ideas in Science </span> </button> <div class="accordion__panel" id="acc-panel-ideas-in-science" data-accordion="panel" aria-labelledby="acc-button-ideas-in-science" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/process-of-science/49/theories-hypotheses-and-laws/177">Theories, Hypotheses, and Laws</a></li> <li><a href="/en/library/process-of-science/49/scientific-controversy/181">Scientific Controversy</a></li> <li><a href="/en/library/process-of-science/49/creativity-in-science/182">Creativity in Science</a></li> </ul> </div> <button class="accordion__button" id="acc-button-research-methods" data-accordion="button" aria-controls="acc-panel-research-methods" aria-expanded="false"> <span class="accordion__button__label"> Research Methods </span> </button> <div class="accordion__panel" id="acc-panel-research-methods" data-accordion="panel" aria-labelledby="acc-button-research-methods" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/process-of-science/49/the-practice-of-science/148">The Practice of Science</a></li> <li><a href="/en/library/process-of-science/49/experimentation-in-scientific-research/150">Experimentation in Scientific Research</a></li> <li><a href="/en/library/process-of-science/49/description-in-scientific-research/151">Description in Scientific Research</a></li> <li><a href="/en/library/process-of-science/49/comparison-in-scientific-research/152">Comparison in Scientific Research</a></li> <li><a href="/en/library/process-of-science/49/modeling-in-scientific-research/153">Modeling in Scientific Research</a></li> </ul> </div> <button class="accordion__button" id="acc-button-data" data-accordion="button" aria-controls="acc-panel-data" aria-expanded="false"> <span class="accordion__button__label"> Data </span> </button> <div class="accordion__panel" id="acc-panel-data" data-accordion="panel" aria-labelledby="acc-button-data" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/process-of-science/49/data-analysis-and-interpretation/154">Data Analysis and Interpretation</a></li> <li><a href="/en/library/process-of-science/49/uncertainty-error-and-confidence/157">Uncertainty, Error, and Confidence</a></li> <li><a href="/en/library/process-of-science/49/statistics-in-science/155">Statistics in Science</a></li> <li><a href="/en/library/process-of-science/49/using-graphs-and-visual-data-in-science/156">Using Graphs and Visual Data in Science</a></li> </ul> </div> <button class="accordion__button" id="acc-button-scientific-communication" data-accordion="button" aria-controls="acc-panel-scientific-communication" aria-expanded="false"> <span class="accordion__button__label"> Scientific Communication </span> </button> <div class="accordion__panel" id="acc-panel-scientific-communication" data-accordion="panel" aria-labelledby="acc-button-scientific-communication" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/process-of-science/49/understanding-scientific-journals-and-articles/158">Understanding Scientific Journals and Articles</a></li> <li><a href="/en/library/process-of-science/49/utilizing-the-scientific-literature/173">Utilizing the Scientific Literature</a></li> <li><a href="/en/library/process-of-science/49/peer-review-in-scientific-publishing/159">Peer Review in Scientific Publishing</a></li> <li><a href="/en/library/process-of-science/49/the-how-and-why-of-scientific-meetings/186">The How and Why of Scientific Meetings</a></li> </ul> </div> </div> </div> <button class="accordion__button" id="acc-button-scientists-and-research" data-accordion="button" aria-controls="acc-panel-scientists-and-research" aria-expanded="false"> <span class="accordion__button__label"> Scientists and Research </span> </button> <div class="accordion__panel" id="acc-panel-scientists-and-research" data-accordion="panel" aria-labelledby="acc-button-scientists-and-research" role="region"> <div class="accordion accordion--secondary"> <button class="accordion__button" id="acc-button-scientific-research" data-accordion="button" aria-controls="acc-panel-scientific-research" aria-expanded="false"> <span class="accordion__button__label"> Scientific Research </span> </button> <div class="accordion__panel" id="acc-panel-scientific-research" data-accordion="panel" aria-labelledby="acc-button-scientific-research" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/scientists-and-research/58/collaborative-research-in-the-arctic-towards-understanding-climate-change/183">Collaborative Research in the Arctic Towards Understanding Climate Change</a></li> <li><a href="/en/library/scientists-and-research/58/from-stable-chromosomes-to-jumping-genes/184">From Stable Chromosomes to Jumping Genes</a></li> <li><a href="/en/library/scientists-and-research/58/an-elegant-experiment-to-test-the-process-of-dna-replication/187">An Elegant Experiment to Test the Process of DNA Replication</a></li> <li><a href="/en/library/scientists-and-research/58/the-founding-of-neuroscience/233">The Founding of Neuroscience</a></li> <li><a href="/en/library/scientists-and-research/58/tracking-endangered-jaguars-across-the-border/189">Tracking Endangered Jaguars across the Border</a></li> <li><a href="/en/library/scientists-and-research/58/atmospheric-chemistry-research-that-changed-global-policy/211">Atmospheric Chemistry Research that Changed Global Policy</a></li> <li><a href="/en/library/scientists-and-research/58/revolutionizing-medicine-with-monoclonal-antibodies/220">Revolutionizing Medicine with Monoclonal Antibodies</a></li> <li><a href="/en/library/scientists-and-research/58/uncovering-the-mysteries-of-chronic-mountain-sickness/238">Uncovering the Mysteries of Chronic Mountain Sickness</a></li> </ul> </div> <button class="accordion__button" id="acc-button-profiles-in-science" data-accordion="button" aria-controls="acc-panel-profiles-in-science" aria-expanded="false"> <span class="accordion__button__label"> Profiles in Science </span> </button> <div class="accordion__panel" id="acc-panel-profiles-in-science" data-accordion="panel" aria-labelledby="acc-button-profiles-in-science" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/scientists-and-research/58/luis-e.-miramontes/232">Luis E. Miramontes</a></li> <li><a href="/en/library/scientists-and-research/58/bernardo-houssay/237">Bernardo Houssay</a></li> <li><a href="/en/library/scientists-and-research/58/craig-lee/256">Craig Lee</a></li> <li><a href="/en/library/scientists-and-research/58/david-ho/241">David Ho</a></li> <li><a href="/en/library/scientists-and-research/58/louis-tompkins-wright/244">Louis Tompkins Wright</a></li> <li><a href="/en/library/scientists-and-research/58/carlos-j.-finlay/217">Carlos J. Finlay</a></li> <li><a href="/en/library/scientists-and-research/58/cecilia-payne/290">Cecilia Payne</a></li> <li><a href="/en/library/scientists-and-research/58/jazmin-scarlett/291">Jazmin Scarlett</a></li> <li><a href="/en/library/scientists-and-research/58/ramari-stewart/292">Ramari Stewart</a></li> <li><a href="/en/library/scientists-and-research/58/johnson-cerda/300">Johnson Cerda</a></li> <li><a href="/en/library/scientists-and-research/58/ellen-ochoa/201">Ellen Ochoa</a></li> <li><a href="/en/library/scientists-and-research/58/ruth-benerito/205">Ruth Benerito</a></li> <li><a href="/en/library/scientists-and-research/58/franklin-chang-díaz/219">Franklin Chang Díaz</a></li> <li><a href="/en/library/scientists-and-research/58/percy-lavon-julian/221">Percy Lavon Julian</a></li> <li><a href="/en/library/scientists-and-research/58/luis-walter-alvarez/229">Luis Walter Alvarez</a></li> <li><a href="/en/library/scientists-and-research/58/france-anne-dominic-córdova/230">France Anne-Dominic Córdova</a></li> </ul> </div> </div> </div> </div> </div> </li> <li>  <button class="button" data-toggle="dropdown">Biology </button> <div class="nav__dropdown box-shadow-1 padding-1"> <div class="accordion accordion--secondary font-size-sm"> <div class="accordion accordion--secondary"> <button class="accordion__button" id="acc-sub-button-biological-molecules" data-accordion="button" aria-controls="acc-sub-panel-biological-molecules" aria-expanded="false"> <span class="accordion__button__label"> Biological Molecules </span> </button> <div class="accordion__panel" id="acc-sub-panel-biological-molecules" data-accordion="panel" aria-labelledby="acc-sub-button-biological-molecules" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/biology/2/carbohydrates/61">Carbohydrates</a></li> <li><a href="/en/library/biology/2/fats-and-proteins/62">Fats and Proteins</a></li> <li><a href="/en/library/biology/2/biological-proteins/243">Biological Proteins</a></li> <li><a href="/en/library/biology/2/blood-biology-i/242">Blood Biology I</a></li> <li><a href="/en/library/biology/2/lipids/207">Lipids</a></li> </ul> </div> <button class="accordion__button" id="acc-sub-button-cell-biology" data-accordion="button" aria-controls="acc-sub-panel-cell-biology" aria-expanded="false"> <span class="accordion__button__label"> Cell Biology </span> </button> <div class="accordion__panel" id="acc-sub-panel-cell-biology" data-accordion="panel" aria-labelledby="acc-sub-button-cell-biology" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/biology/2/discovery-and-structure-of-cells/64">Discovery and Structure of Cells</a></li> <li><a href="/en/library/biology/2/respiration/285">Respiration</a></li> <li><a href="/en/library/biology/2/membranes-i/198">Membranes I</a></li> <li><a href="/en/library/biology/2/membranes-ii/204">Membranes II</a></li> <li><a href="/en/library/biology/2/cellular-organelles-i/195">Cellular Organelles I</a></li> <li><a href="/en/library/biology/2/cell-division-i/196">Cell Division I</a></li> <li><a href="/en/library/biology/2/cell-division-ii/212">Cell Division II</a></li> <li><a href="/en/library/biology/2/membranes-and-chemical-transport/106">Membranes and Chemical Transport</a></li> </ul> </div> <button class="accordion__button" id="acc-sub-button-energy-in-living-systems" data-accordion="button" aria-controls="acc-sub-panel-energy-in-living-systems" aria-expanded="false"> <span class="accordion__button__label"> Energy in Living Systems </span> </button> <div class="accordion__panel" id="acc-sub-panel-energy-in-living-systems" data-accordion="panel" aria-labelledby="acc-sub-button-energy-in-living-systems" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/biology/2/energy-metabolism-i/215">Energy Metabolism I</a></li> <li><a href="/en/library/biology/2/energy-metabolism-ii/225">Energy Metabolism II</a></li> <li><a href="/en/library/biology/2/photosynthesis-i/192">Photosynthesis I</a></li> </ul> </div> <button class="accordion__button" id="acc-sub-button-evolutionary-biology" data-accordion="button" aria-controls="acc-sub-panel-evolutionary-biology" aria-expanded="false"> <span class="accordion__button__label"> Evolutionary Biology </span> </button> <div class="accordion__panel" id="acc-sub-panel-evolutionary-biology" data-accordion="panel" aria-labelledby="acc-sub-button-evolutionary-biology" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/biology/2/origins-of-life-i/226">Origins of Life I</a></li> <li><a href="/en/library/biology/2/origins-of-life-ii/227">Origins of Life II</a></li> <li><a href="/en/library/biology/2/extinction/295">Extinction</a></li> <li><a href="/en/library/biology/2/mass-extinctions/294">Mass Extinctions</a></li> <li><a href="/en/library/biology/2/charles-darwin-i/110">Charles Darwin I</a></li> <li><a href="/en/library/biology/2/charles-darwin-ii/111">Charles Darwin II</a></li> <li><a href="/en/library/biology/2/charles-darwin-iii/112">Charles Darwin III</a></li> <li><a href="/en/library/biology/2/adaptation/68">Adaptation</a></li> <li><a href="/en/library/biology/2/taxonomy-i/70">Taxonomy I</a></li> <li><a href="/en/library/biology/2/taxonomy-ii/89">Taxonomy II</a></li> <li><a href="/en/library/biology/2/introduction-to-paleoanthropology/258">Introduction to Paleoanthropology</a></li> <li><a href="/en/library/biology/2/the-piltdown-hoax/263">The Piltdown Hoax</a></li> <li><a href="/en/library/biology/2/future-of-human-evolution/259">Future of Human Evolution</a></li> </ul> </div> <button class="accordion__button" id="acc-sub-button-genetics" data-accordion="button" aria-controls="acc-sub-panel-genetics" aria-expanded="false"> <span class="accordion__button__label"> Genetics </span> </button> <div class="accordion__panel" id="acc-sub-panel-genetics" data-accordion="panel" aria-labelledby="acc-sub-button-genetics" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/biology/2/inheritance/129">Inheritance</a></li> <li><a href="/en/library/biology/2/independent-assortment/145">Independent Assortment</a></li> <li><a href="/en/library/biology/2/dna-i/149">DNA I</a></li> <li><a href="/en/library/biology/2/dna-ii/160">DNA II</a></li> <li><a href="/en/library/biology/2/dna-iii/180">DNA III</a></li> <li><a href="/en/library/biology/2/tracking-human-ancestry/248">Tracking Human Ancestry</a></li> <li><a href="/en/library/biology/2/gene-expression/214">Gene Expression</a></li> <li><a href="/en/library/biology/2/population-genetics/249">Population Genetics</a></li> </ul> </div> <button class="accordion__button" id="acc-sub-button-ecology" data-accordion="button" aria-controls="acc-sub-panel-ecology" aria-expanded="false"> <span class="accordion__button__label"> Ecology </span> </button> <div class="accordion__panel" id="acc-sub-panel-ecology" data-accordion="panel" aria-labelledby="acc-sub-button-ecology" role="region"> <ul class="nav text-color-link"> <li class="current">Biodiversity I</li> <li><a href="/en/library/biology/2/ecosystem-services/279">Ecosystem Services</a></li> <li><a href="/en/library/biology/2/animal-ecology/283">Animal Ecology</a></li> <li><a href="/en/library/biology/2/biodiversity-ii/281">Biodiversity II</a></li> <li><a href="/en/library/biology/2/animal-behavior/286">Animal Behavior</a></li> <li><a href="/en/library/biology/2/population-biology/287">Population Biology</a></li> <li><a href="/en/library/biology/2/trophic-ecology/293">Trophic Ecology</a></li> </ul> </div> </div> </div> </div> </li> </ul> </nav>  <div id="theTop"></div> <main id="skip-header-content"> <div class="margin-bottom-5"> <article class="container wide module"> <header class="grid grid--sidebar-right module__header"> <div class="module__header__title"> <span class="subcategory"> <strong><em>Ecology</em></strong> </span> <h1>Biodiversity I: <sub><em>Definitions and patterns of diversity</em></sub></h1> <p class="byline">by Devin Reese, PhD.</p> <nav class="module__header__tabs"> <ul class="tabs-nav tabs-nav--horizontal library"> <li> <a href="/en/library/biology/2/biodiversity-i/276/reading" aria-current="page" >Reading</a> </li> <li> <a href="/en/library/biology/2/biodiversity-i/276/quiz">Quiz</a> </li> <li> <a href="/en/library/biology/2/biodiversity-i/276/resources">Teach with this</a> </li> </ul> </nav> </div> </header> <hr class="divider"/>   <div class="grid grid--sidebar-right grid--divider"> <div class="order-2 order-1--lg module__main"> <div class="narrow margin-x-auto margin-y-5"> <div class="accordion margin-bottom-5">  <button class="accordion__button" id="acc-button-key-concepts" data-accordion="button" aria-controls="acc-panel-key-concepts" aria-expanded="true" tabindex="0"> Did you know? </button> <div class="accordion__panel shown show" id="acc-panel-key-concepts" data-accordion="panel" aria-labelledby="acc-button-key-concepts" role="region"> <div class="accordion__panel__content"> <p>Did you know that the sudden disappearance of a single species risks collapsing an entire ecosystem? In fact, the biological diversity (biodiversity) of our ecosystems is vital to the continued existence of life on Earth. Scientists recognize three levels of biodiversity: species diversity, genetic diversity, and ecosystem diversity. Each level impacts the others, and to understand their interactions, scientists are looking to a variety of ecosystems for answers.</p> </div> </div>  <button class="accordion__button" id="acc-button-table-of-contents" data-accordion="button" aria-controls="acc-panel-table-of-contents" aria-expanded="false" tabindex="0"> Key concepts </button> <div class="accordion__panel" id="acc-panel-table-of-contents" data-accordion="panel" aria-labelledby="acc-button-table-of-contents" role="region" aria-hidden="true"> <div class="accordion__panel__content"> <ul class="bulleted"><li><p>On the basis of physical characteristics, genetic markers, and interactions collected through multiple methods, scientists define biodiversity as the variety of life on Earth on multiple levels: species, genetic, ecosystem.</li></p> <li><p>Measurements of species-level biodiversity include species richness and evenness, which are calculated from samples of species distributions within and across ecosystems.</li></p> <li><p>Scientific studies of biodiversity find that it correlates with latitude, landscape heterogeneity, and specific biogeographical pattern features like islands.</li></p> <li><p>The functioning of Earth’s systems that sustain life depends on biodiversity at all levels, evidenced by the poor health of ecosystems with low biodiversity. </li></p></ul> </div> </div>  <button class="accordion__button" id="acc-button-terms-you-should-know" data-accordion="button" aria-controls="acc-panel-terms-you-should-know" aria-expanded="false" tabindex="0"> Terms you should know </button> <div class="accordion__panel" id="acc-panel-terms-you-should-know" data-accordion="panel" aria-labelledby="acc-button-terms-you-should-know" role="region" aria-hidden="true"> <div class="accordion__panel__content"> <dl> <dt><a href="/en/glossary/view/species">Species </a></dt> <dd> Organisms capable of interbreeding </dd> <dt><a href="/en/glossary/view/ecosystem">Ecosystem </a></dt> <dd> A community of organisms and its environment </dd> <dt><a href="/en/glossary/view/latitude">Latitude </a></dt> <dd> Measurement of north or south of Equator </dd> <dt><a href="/en/glossary/view/photosynthesis">Photosynthesis </a></dt> <dd> Process by which plants convert sunlight into energy</dd> </dl> </div> </div> </div> <hr class="border-color-dark" /> <section> <div class="container narrow"> <blockquote class="blockquote-hanging"> <p> It’s no mystery why indigenous groups are so adept at protecting biodiversity. For generations, we have accumulated intimate and detailed knowledge of the specific ecosystems where we live. We know every aspect of the plant and animal life, from mountain-tops to ocean floors. </p> <footer> <cite> <strong>Victoria Tauli-Corpuz</strong> the UN’s Special Rapporteur for Indigenous Peoples, 2019 <cite> </footer> </blockquote> <p>Step outside and spend a few minutes looking around. Make a rough count of how many different types of living things (including humans) you see. Look closely. Include tiny things like mosquitoes, moss, or mites. If you don’t know what it is, that’s fine. Just count them up. By counting, you have taken a step towards understanding the <mark class="term" data-term="biodiversity" data-term-def="The variety and abundance of life and its ecological context, including the different kinds of organisms, the numbers of species, the&hellip;" data-term-url="/en/glossary/view/biodiversity/875">biodiversity</mark> around you. You are making an approximation of how many species—types of <mark class="term" data-term="organism" data-term-def="Any connected living system, such as an animal, plant, fungus, or bacterium. Organisms may be composed of a single cell or&hellip;" data-term-url="/en/glossary/view/organism/2171">organisms</mark> able to breed with each other—live in your neighborhood.</p> <p>Ask yourself a few questions: How many types of living things did you find? Which types are the most common? Why might they thrive while others don’t? These questions are at the <mark class="term" data-term="core" data-term-def="The innermost layer of the Earth, which starts at ~2900 km depth. The core is composed mainly of iron and consists&hellip;" data-term-url="/en/glossary/view/core/1663">core</mark> of understanding biodiversity and the factors that determine it.</p> <p><section id="toc_1" class=""> <h2>What is biodiversity?</h2></p> <p>The term “biodiversity,” a contraction of “biological diversity,” refers to the variety of life on Earth. The term stems from the Greek word bios (life) and the Latin word diversitas (difference or variety). In combination, the two words describe the enormous range of living things from tiny <mark class="term" data-term="bacteria" data-term-def="(plural of bacterium) A large group of one-celled organisms that are found almost everywhere." data-term-url="/en/glossary/view/bacteria/8679">bacteria</mark> to the largest animal, the Antarctic blue whale, or an even larger <mark class="term" data-term="organism" data-term-def="Any connected living system, such as an animal, plant, fungus, or bacterium. Organisms may be composed of a single cell or&hellip;" data-term-url="/en/glossary/view/organism/2171">organism</mark> called a honey fungus that grows to several miles in diameter (Casselman, 2007).</p> <p>The human understanding of <mark class="term" data-term="biodiversity" data-term-def="The variety and abundance of life and its ecological context, including the different kinds of organisms, the numbers of species, the&hellip;" data-term-url="/en/glossary/view/biodiversity/875">biodiversity</mark> likely began long ago. Our hunter-gatherer ancestors would have needed to be aware of the diversity of plant and animal life they depended on for survival (Tallavaara et al., 2017). <mark id="ngss-102" class="ngss">By the 300s <mark class="term" data-term="BCE" data-term-def="An abbreviation for Before the Common Era, which is a designation for the years prior to year 1 of the Gregorian&hellip;" data-term-url="/en/glossary/view/BCE/3720">BCE</mark>, the Greek philosopher <mark class="term" data-term="Aristotle" data-term-def="A Greek philosopher born in Stagira (384-322 BCE). He joined Plato's Academy in Athens (then being run by Eudoxus) at the&hellip;" data-term-url="/en/glossary/view/Aristotle/4466">Aristotle</mark> observed that plants and animals could be sorted into <mark class="term" data-term="group" data-term-def="A column of elements in the periodic table." data-term-url="/en/glossary/view/group/8566">groups</mark> based on how they looked and behaved. His <mark class="term" data-term="work" data-term-def="A process that occurs when a force acts over a distance, as when an object is moved. Work equals the multiple&hellip;" data-term-url="/en/glossary/view/work/1502">work</mark> led to the approach we use today to classify and assign scientific names to living things (see our <a href="https://www.visionlearning.com/en/library/Biology/2/Taxonomy-I/70" target="_blank" rel="noopener">Taxonomy I: What's in a name? module</a>). </mark></p> <p>Since Aristotle’s time, we’ve come a long way in describing biodiversity. The official definition is “the variability among living organisms from all sources, including, inter alia, <mark class="term" data-term="terrestrial" data-term-def="In Environmental Science: related to, located on, or living on land. Not aquatic. <br> <br> In Astronomy: related to or occurring on Earth. Not&hellip;" data-term-url="/en/glossary/view/terrestrial/5618">terrestrial</mark>, marine and other <mark class="term" data-term="aquatic" data-term-def="Related to, located in, or living in or on a body of water. Not terrestrial. Aquatic includes both freshwater and saltwater&hellip;" data-term-url="/en/glossary/view/aquatic/5619">aquatic</mark> <mark class="term" data-term="ecosystem" data-term-def="The complex of a community of organisms and its environment, functioning as a unit." data-term-url="/en/glossary/view/ecosystem/2174">ecosystems</mark> and the ecological complexes of which they are part; this includes diversity within <mark class="term" data-term="species" data-term-def="1. In biological classifications, it is the lowest and most basic unit of the Linnaean taxonomic hierarchy (although it is also&hellip;" data-term-url="/en/glossary/view/species/893">species</mark>, between species and of ecosystems” (Convention on Biological Diversity, 2006). Biodiversity includes the variety of living organisms, the diversity of <mark class="term" data-term="gene" data-term-def="Material (usually DNA) that is inherited from a parent and which encodes for a cellular component important for some cellular function." data-term-url="/en/glossary/view/gene/3294">genes</mark> they carry, and the variety of ecosystems in which they live. This official definition includes three levels of biodiversity: species diversity, genetic diversity, and ecosystem diversity.</p></section> <section id="toc_2"> <h2>Species biodiversity</h2><p><mark id="ngss-103" class="ngss">Species diversity is the most commonly measured level of <mark class="term" data-term="biodiversity" data-term-def="The variety and abundance of life and its ecological context, including the different kinds of organisms, the numbers of species, the&hellip;" data-term-url="/en/glossary/view/biodiversity/875">biodiversity</mark>. <mark class="term" data-term="current" data-term-def="a flow, as of electricity or water. In oceanography and hydrology, a channel of water that flows together at the same velocity" data-term-url="/en/glossary/view/current/8278">Current</mark> estimates suggest that between 5 million and 10 million living <mark class="term" data-term="species" data-term-def="1. In biological classifications, it is the lowest and most basic unit of the Linnaean taxonomic hierarchy (although it is also&hellip;" data-term-url="/en/glossary/view/species/893">species</mark> currently exist on Earth (Costello et al., 2013; Wilson, 2018). Why is there such a huge range in the estimates? To date, about 2 million species have been accounted for, meaning they have been assigned formal scientific names by people who discovered them. Based on the rates of naming of new species, the majority have yet to be discovered. While scientists think they have identified nearly all bird and mammal species, there are millions of species of fungi, <mark class="term" data-term="bacteria" data-term-def="(plural of bacterium) A large group of one-celled organisms that are found almost everywhere." data-term-url="/en/glossary/view/bacteria/8679">bacteria</mark>, and other <mark class="term" data-term="organism" data-term-def="Any connected living system, such as an animal, plant, fungus, or bacterium. Organisms may be composed of a single cell or&hellip;" data-term-url="/en/glossary/view/organism/2171">organisms</mark> that have yet to be identified. For example, the approximately 100,000 known fungi are thought to be less than ten percent of existing species (Sigwart et al., 2018). So, estimates of 5 to 10 million total species on Earth are based on the rate of discovery of new species and projections of how many more are likely to turn up.</mark> </p></section> <section id="toc2_1"><h3>Counting species</h3><p>Counting all the <mark class="term" data-term="species" data-term-def="1. In biological classifications, it is the lowest and most basic unit of the Linnaean taxonomic hierarchy (although it is also&hellip;" data-term-url="/en/glossary/view/species/893">species</mark> on Earth is no simple task. Think about the <mark class="term" data-term="magnitude" data-term-def="Magnitude is a number assigned to a quantity and refers to the size or extent of something. There are several differing&hellip;" data-term-url="/en/glossary/view/magnitude/11226">magnitude</mark> of 5 to 10 million species compared to the total from your own local count.</p> <p><mark id="ngss-104" class="ngss">One of the earliest published counts of species diversity was made in 1982 by American biologist Terry Erwin. He wondered how many species of beetles and other arthropods (invertebrates with jointed legs) lived in the tropics. Erwin “fogged” 19 tropical trees with insecticides and counted nearly 1,200 species of beetles that fell out. From his <mark class="term" data-term="observation" data-term-def="1. The act of noticing something. 2. A record of that which has been noticed." data-term-url="/en/glossary/view/observation/8255">observations</mark> and counts, Erwin noted various beetles’ dependence on particular tree species. By estimating about 50,000 species of tropical trees, Erwin came up with a staggering tally of 30,000 species of beetles and other tropical arthropods (Erwin, 1982).</mark></p> <p>While many of the assumptions behind Erwin’s estimates are debated, such as the <mark class="term" data-term="degree" data-term-def="[<strong>temperature</strong>] One graduated unit of measure on a Fahrenheit or Celsius temperature scale. On the Kelvin scale, graduations are called Kelvins. <br> <br> [<strong>geometry</strong>]&hellip;" data-term-url="/en/glossary/view/degree/8535">degree</mark> to which beetles are specialized to certain trees, his <mark class="term" data-term="work" data-term-def="A process that occurs when a force acts over a distance, as when an object is moved. Work equals the multiple&hellip;" data-term-url="/en/glossary/view/work/1502">work</mark> spawned a flurry of interest in tallying up all the species on Earth (Ødegaard et al., 2000). Scientists all over the world are collectively trying to figure out global species diversity. Fogging and other collection techniques are still used today, but judiciously and alongside other <mark class="term" data-term="method" data-term-def="A procedure or process; a systematic way of performing a task or conducting research." data-term-url="/en/glossary/view/method/8238">methods</mark> that are less destructive. For example, insects are sampled by attracting them to <mark class="term" data-term="light" data-term-def="A form of electromagnetic radiation. Visible light is that associated with stimulating the organs of sight, which for normal human&hellip;" data-term-url="/en/glossary/view/light/1498">lights</mark> and netting, after which they can be released (Montgomery et al., 2021).</p> <p><mark id="ngss-105" class="ngss">Today, in calculating species diversity, scientists include not only “richness” (the number of different species counted) but also “abundance” (how many members) of each species counted. Relative abundance gives you information about the species’ influence on the <mark class="term" data-term="ecosystem" data-term-def="The complex of a community of organisms and its environment, functioning as a unit." data-term-url="/en/glossary/view/ecosystem/2174">ecosystem</mark>. For example, while an individual grass plant may have a small impact on the characteristics of an ecosystem relative to an oak tree, the sheer abundance of grasses in a meadow ecosystem makes it an excellent <mark class="term" data-term="habitat" data-term-def="The place or type of environment where a wild plant, animal, or other organism naturally lives or grows." data-term-url="/en/glossary/view/habitat/5593">habitat</mark> for animals like grass snakes and voles.</mark></p></section> <section id="toc2_2"><h3>Ways of knowing</h3><p>Indigenous Peoples’ ways of knowing are particularly valuable in estimating <mark class="term" data-term="biodiversity" data-term-def="The variety and abundance of life and its ecological context, including the different kinds of organisms, the numbers of species, the&hellip;" data-term-url="/en/glossary/view/biodiversity/875">biodiversity</mark>. In fact, <mark class="term" data-term="research" data-term-def="A study or an investigation." data-term-url="/en/glossary/view/research/8257">research</mark> has shown that indigenous and other local knowledge about biodiversity is as accurate as <mark class="term" data-term="data" data-term-def="(plural form of <b>datum</b>) A collection of pieces of information, generally taking the form of numbers, text, bits, or facts, that&hellip;" data-term-url="/en/glossary/view/data/3729">data</mark> collected via Western science techniques (Danielsen et al., 2014). <mark id="ngss-106" class="ngss">Indigenous homelands tend to have high biodiversity because of the ways they are managed to sustain <mark class="term" data-term="natural resources" data-term-def="Materials produced through or contained within Earth's natural systems and used by humans and other species. They include minerals and soil,&hellip;" data-term-url="/en/glossary/view/natural+resources/5617">natural resources</mark> that people depend on directly. For example, in New Zealand, Māori whale expert Ramari Oliphant Stewart was mentored in the natural <mark class="term" data-term="environment" data-term-def="The conditions that surround and affect an organism." data-term-url="/en/glossary/view/environment/8270">environment</mark> by her elders from the Ngāti Awa, Rongomaiwahine, and Ngāti Mahuta tribes. At age 10, she became a “whale rider”, which signifies someone with special knowledge about and relationship to whales (Morris, 2020).</mark></p> <p>Discovering new <mark class="term" data-term="species" data-term-def="1. In biological classifications, it is the lowest and most basic unit of the Linnaean taxonomic hierarchy (although it is also&hellip;" data-term-url="/en/glossary/view/species/893">species</mark> and adding them to the tally of biodiversity on Earth requires continued global collaboration across different communities and knowledge keepers. A project called The Encyclopedia of Life (EOL) is cataloging all living species into an open-source biodiversity information repository that anyone can add to and access. Similarly, the Map of Life (MOL) project is a similar collaborative effort to map the locations of every species in the world.</p> <p>However, biodiversity goes even deeper than the species level.</p> <div class="comprehension-checkpoint margin-y-4"> <h6 class="comprehension-checkpoint__header"> <span> <span class="icon icon-question"></span> </span> Comprehension Checkpoint </h6> <form class="" name="cc12349"> <div class="form-entry"> <div class="form-entry__field"> <span class="form-entry__field__label">True or false: Scientists estimate between 5 million and 10 million species currently exist on Earth. </span> <div class="form-entry__option"> <div class="form-entry__option__radio" data-answer="correct"> <label> <input id="q1-12349-0-option-a" name="quiz-option-12349" type="radio" value="True" > <span class="option__label"> <span class="screen-reader-only">a.</span> True </span> </label> <span class="quiz__response" id="response-12349-0"> <strong>Correct!</strong> </span> </div> <div class="form-entry__option__radio" data-answer="incorrect"> <label> <input id="q1-12349-1-option-b" name="quiz-option-12349" type="radio" value="False" > <span class="option__label"> <span class="screen-reader-only">b.</span> False </span> </label> <span class="quiz__response" id="response-12349-1"> <strong>Incorrect.</strong> </span> </div> </div> </div> </div> </form> </div> </section> <section id="toc_3"> <h2>Genetic diversity</h2><p>Cataloging <mark class="term" data-term="species" data-term-def="1. In biological classifications, it is the lowest and most basic unit of the Linnaean taxonomic hierarchy (although it is also&hellip;" data-term-url="/en/glossary/view/species/893">species</mark> by the way they look is a reasonable way to understand Earth’s diverse <mark class="term" data-term="ecosystem" data-term-def="The complex of a community of organisms and its environment, functioning as a unit." data-term-url="/en/glossary/view/ecosystem/2174">ecosystems</mark>. However, <mark class="term" data-term="gene" data-term-def="Material (usually DNA) that is inherited from a parent and which encodes for a cellular component important for some cellular function." data-term-url="/en/glossary/view/gene/3294">genes</mark> “code for” (determine) the very characteristics that set species apart from one another (see our <a href="https://www.visionlearning.com/en/library/Biology/2/DNA-II/160" target="_blank" rel="noopener">DNA II: The Structure of <mark class="term" data-term="DNA" data-term-def="Deoxyribonucleic acid. A double-stranded nucleic acid containing the sugar 2-deoxy-D-ribose. A constituent of cellular nuclear material responsible for encoding&hellip;" data-term-url="/en/glossary/view/DNA/1604">DNA</mark> module</a>). <mark id="ngss-107" class="ngss">As the raw material for <mark class="term" data-term="natural selection" data-term-def="The process whereby characteristics that promote survival and reproduction are passed on to future generations, so these characteristics become more frequent&hellip;" data-term-url="/en/glossary/view/natural+selection/11402">natural selection</mark>, genes are the building blocks of species diversity as it changes over time (Hughes et al., 2008). All the variability that makes life capable of adapting to changing environmental conditions has accumulated within the pool of DNA. This is genetic diversity</mark> (Convention on Biological Diversity, 2021).</p> <p>Genetic diversity helps <mark class="term" data-term="buffer" data-term-def="An aqueous solution containing a weak acid and its conjugate base that moderates pH changes when acid or base is added.&hellip;" data-term-url="/en/glossary/view/buffer/1576">buffer</mark> species against environmental change by ensuring that at least some individuals survive disease or other catastrophes. It’s like keeping money in different places to buffer against change (Lynch, 2016). You might keep some at home, some at the bank, and maybe some in a car or other location. If your home is robbed or the bank fails, you still have part of your money elsewhere. <mark id="ngss-108" class="ngss">Similarly, in a <mark class="term" data-term="population" data-term-def="In biology, the population is all individuals of a certain kind of plant or animal that live in a particular habitat.&hellip;" data-term-url="/en/glossary/view/population/8283">population</mark> of <mark class="term" data-term="organism" data-term-def="Any connected living system, such as an animal, plant, fungus, or bacterium. Organisms may be composed of a single cell or&hellip;" data-term-url="/en/glossary/view/organism/2171">organisms</mark> with high genetic diversity, some are likely to be resistant to a particular disease or <mark class="term" data-term="parasite" data-term-def="An organism that lives on or in a host organism of another species. Parasites derive their food from and are detrimental&hellip;" data-term-url="/en/glossary/view/parasite/5272">parasite</mark> and survive to reproduce and ensure the continuation of the species.</mark></p> <p>The consequences of losing genetic diversity are apparent in many areas, including agriculture. As industrial farms have worked to identify and use high-performing individual species, they have also reduced the genetic diversity of industrial crops. As a result, industrial crops are at a much higher risk of being wiped out by disease or parasites. <mark id="ngss-109" class="ngss">For example, large-scale loss of corn to the Southern Corn Leaf Blight epidemic of 1970-71 brought attention to the importance of genetic diversity. One-billion dollars of U.S. corn was wiped out by a fungal infection because the corn genes had become so homogeneous (lacking diversity) that most of the crop lacked resistance to the disease caused by the fungus (Bruns, 2017).</mark></p> <p>The perils of losing genetic and species diversity highlights the importance of being able to measure and track it. While <mark class="term" data-term="research" data-term-def="A study or an investigation." data-term-url="/en/glossary/view/research/8257">research</mark> on DNA dates to the late 1800s, the first successes in determining an actual DNA sequence of genes came in the 1970s (Jou et al., 1972). <mark id="ngss-110" class="ngss">Building on these advances in 2003, Canadian molecular biologist Paul D. N. Hebert developed a technique called DNA barcoding that identifies species from a short segment of the genetic code (Hebert at al., 2003). A DNA barcode is a genetic signature of an organism. It’s like the codes you can scan to read the price of a <mark class="term" data-term="product" data-term-def="The material that is formed as a result of a chemical reaction. Written on the right side of a chemical equation.&hellip;" data-term-url="/en/glossary/view/product/1569">product</mark> or look at a restaurant menu, except a DNA barcode provides information about the DNA of organisms (Figure 1). </mark></p> <div class="figure"> <figure> <button class="lightbox-button lightbox-button--icon" data-lightbox=""> <img src="/img/library/modules/mid276/Image/VLObject-12389-22052309055253.jpg" alt="Figure 1: Depiction of the relationship of a short DNA barcode to the entire DNA molecule from an individual of a species." /> </button> <figcaption> <p><strong>Figure 1:</strong> Depiction of the relationship of a short DNA barcode to the entire DNA molecule from an individual of a species.</p> <span class="credit">image ©CC-SA Larissa Fruehe</span> </figcaption> </figure> </div> <p>Hebert heads the International Barcode of Life (iBOL) Consortium, an international <mark class="term" data-term="group" data-term-def="A column of elements in the periodic table." data-term-url="/en/glossary/view/group/8566">group</mark> of scientists that aim to collect the genetic signature, or barcode, of every <mark class="term" data-term="species" data-term-def="1. In biological classifications, it is the lowest and most basic unit of the Linnaean taxonomic hierarchy (although it is also&hellip;" data-term-url="/en/glossary/view/species/893">species</mark> on Earth. It’s like the Encyclopedia of Life, but catalogs <mark class="term" data-term="DNA" data-term-def="Deoxyribonucleic acid. A double-stranded nucleic acid containing the sugar 2-deoxy-D-ribose. A constituent of cellular nuclear material responsible for encoding&hellip;" data-term-url="/en/glossary/view/DNA/1604">DNA</mark> rather than other features of <mark class="term" data-term="organism" data-term-def="Any connected living system, such as an animal, plant, fungus, or bacterium. Organisms may be composed of a single cell or&hellip;" data-term-url="/en/glossary/view/organism/2171">organisms</mark>. The iBOL database makes genetic diversity information openly available to anyone who wants to access it.</p></section> <section id="toc_4"> <h2>Ecosystem diversity</h2><p>Another way to view <mark class="term" data-term="biodiversity" data-term-def="The variety and abundance of life and its ecological context, including the different kinds of organisms, the numbers of species, the&hellip;" data-term-url="/en/glossary/view/biodiversity/875">biodiversity</mark> is at the level of <mark class="term" data-term="ecosystem" data-term-def="The complex of a community of organisms and its environment, functioning as a unit." data-term-url="/en/glossary/view/ecosystem/2174">ecosystems</mark>. An ecosystem is a community of <mark class="term" data-term="organism" data-term-def="Any connected living system, such as an animal, plant, fungus, or bacterium. Organisms may be composed of a single cell or&hellip;" data-term-url="/en/glossary/view/organism/2171">organisms</mark> interacting with their physical, or nonliving, <mark class="term" data-term="environment" data-term-def="The conditions that surround and affect an organism." data-term-url="/en/glossary/view/environment/8270">environment</mark>. Ecosystem diversity refers to the variety of ecosystems that exist in a defined area, something visible to early naturalists.</p> <p>In the early 1900s, Prussian explorer Alexander von Humboldt laid the foundation for understanding ecosystem diversity, inspired by his expedition to the American tropics. <mark id="ngss-111" class="ngss">Humboldt’s <em>Tableau Physique</em> (1807) was one of the first formal attempts to delineate biodiversity at an ecosystem level. As shown in Figure 2, he mapped plant <mark class="term" data-term="species" data-term-def="1. In biological classifications, it is the lowest and most basic unit of the Linnaean taxonomic hierarchy (although it is also&hellip;" data-term-url="/en/glossary/view/species/893">species</mark> in the Andes Mountains, showing how they changed with altitude.</mark></p> <div class="figure"> <figure> <button class="lightbox-button lightbox-button--icon" data-lightbox=""> <img src="/img/library/modules/mid276/Image/VLObject-12390-22052310052923.jpg" alt="Figure 2: Humboldt’s mapping of vegetation zones in the Andes published in Berghaus, 1851, Physikalischer Atlas." /> </button> <figcaption> <p><strong>Figure 2:</strong> Humboldt’s mapping of vegetation zones in the Andes published in Berghaus, 1851, <em>Physikalischer Atlas.</em></p> <span class="credit">image ©Public Domain</span> </figcaption> </figure> </div> <p>Humboldt’s mapping was ahead of its time. Yet, scientists today recognize the limitations of his mapping, particularly in finding exact upper and lower limits of vegetation types (Moret, 2019).</p> <p><mark id="ngss-112" class="ngss">Compared to <mark class="term" data-term="species" data-term-def="1. In biological classifications, it is the lowest and most basic unit of the Linnaean taxonomic hierarchy (although it is also&hellip;" data-term-url="/en/glossary/view/species/893">species</mark> or genetic diversity, <mark class="term" data-term="ecosystem" data-term-def="The complex of a community of organisms and its environment, functioning as a unit." data-term-url="/en/glossary/view/ecosystem/2174">ecosystem</mark> diversity is harder to measure. The boundaries of most ecosystems are not a sharp line, but instead a gradual <mark class="term" data-term="transition" data-term-def="A change from one stage, form, or state to another." data-term-url="/en/glossary/view/transition/8520">transition</mark> from one community of <mark class="term" data-term="organism" data-term-def="Any connected living system, such as an animal, plant, fungus, or bacterium. Organisms may be composed of a single cell or&hellip;" data-term-url="/en/glossary/view/organism/2171">organisms</mark> to another (Cofrin Center for Biodiversity). A city ecosystem might have an obvious <mark class="term" data-term="boundary" data-term-def="A line or limit that divides one area from another." data-term-url="/en/glossary/view/boundary/8272">boundary</mark>, say between a park and a road, or a coastal area between land and sea. But typically, ecosystem boundaries are less clear. To <mark class="term" data-term="Test" data-term-def="This is a test glossary term." data-term-url="/en/glossary/view/Test/12984">test</mark> this out, look online for an aerial photo of the region you live in, and try to draw lines delineating the ecosystem boundaries.</mark></p> <p>Regardless of whether you look at <mark class="term" data-term="biodiversity" data-term-def="The variety and abundance of life and its ecological context, including the different kinds of organisms, the numbers of species, the&hellip;" data-term-url="/en/glossary/view/biodiversity/875">biodiversity</mark> through a species, genetic, or ecosystem lens, it invites questions: What creates patterns of biodiversity? Why is one area more diverse and another less diverse? As you will see in the next section, the most visible global pattern in biodiversity is how it differs across <mark class="term" data-term="latitude" data-term-def="the angular distance of a place north or south of the Earth’s equator, expressed in degrees, minutes and seconds." data-term-url="/en/glossary/view/latitude/12930">latitude</mark>.</p> <div class="comprehension-checkpoint margin-y-4"> <h6 class="comprehension-checkpoint__header"> <span> <span class="icon icon-question"></span> </span> Comprehension Checkpoint </h6> <form class="" name="cc12364"> <div class="form-entry"> <div class="form-entry__field"> <span class="form-entry__field__label">Biodiversity is most commonly defined at the level of...</span> <div class="form-entry__option"> <div class="form-entry__option__radio" data-answer="correct"> <label> <input id="q1-12364-0-option-a" name="quiz-option-12364" type="radio" value="genes" > <span class="option__label"> <span class="screen-reader-only">a.</span> genes </span> </label> <span class="quiz__response" id="response-12364-0"> <strong>Correct!</strong> </span> </div> <div class="form-entry__option__radio" data-answer="incorrect"> <label> <input id="q1-12364-1-option-b" name="quiz-option-12364" type="radio" value="species" > <span class="option__label"> <span class="screen-reader-only">b.</span> species </span> </label> <span class="quiz__response" id="response-12364-1"> <strong>Incorrect.</strong> </span> </div> </div> </div> </div> </form> </div> </section> <section id="toc_5"> <h2>Biodiversity and latitude</h2><p>Take a look at the map below (Figure 3). Red areas indicate more <mark class="term" data-term="species" data-term-def="1. In biological classifications, it is the lowest and most basic unit of the Linnaean taxonomic hierarchy (although it is also&hellip;" data-term-url="/en/glossary/view/species/893">species</mark>. What do you notice about the distribution of species on Earth?</p> <div class="figure"> <figure> <button class="lightbox-button lightbox-button--icon" data-lightbox=""> <img src="/img/library/modules/mid276/Image/VLObject-12393-22052311052041.jpg" alt="Figure 3: Map of global biodiversity." /> </button> <figcaption> <p><strong>Figure 3:</strong> Map of global biodiversity.</p> <span class="credit">image ©CC BY: Mannion, P. D., Upchurch, P., Benson, R. B. J. & Goswami, A., based on work by Clinton Jenkin</span> </figcaption> </figure> </div> <p><mark id="ngss-113" class="ngss">For at least two centuries, naturalists have noted that <mark class="term" data-term="biodiversity" data-term-def="The variety and abundance of life and its ecological context, including the different kinds of organisms, the numbers of species, the&hellip;" data-term-url="/en/glossary/view/biodiversity/875">biodiversity</mark> increases as you go from the poles to the tropics. This is called a Latitudinal Diversity Gradient (LDG). Inspired by the biodiversity he saw in the Andes, Humboldt mapped the first isothermal (temperature) bands onto the globe. In 1817, he published a map which, while based on limited <mark class="term" data-term="data" data-term-def="(plural form of <b>datum</b>) A collection of pieces of information, generally taking the form of numbers, text, bits, or facts, that&hellip;" data-term-url="/en/glossary/view/data/3729">data</mark>, showed how temperatures change over the globe (Klein, 2018; Humboldt, 1817). Building on Humboldt’s mapping, in 1876, British naturalist Alfred Russell Wallace reported, “Animal life is, on the whole, far more abundant and more varied within the tropics than in any other part of the globe, and a great number of peculiar <mark class="term" data-term="group" data-term-def="A column of elements in the periodic table." data-term-url="/en/glossary/view/group/8566">groups</mark> are found there which never extend into temperate regions.” (Wallace, 1876; Dowle et al., 2013).</mark></p> <p>The tropics are close to the equator (defined as 23.5 <mark class="term" data-term="degree" data-term-def="[<strong>temperature</strong>] One graduated unit of measure on a Fahrenheit or Celsius temperature scale. On the Kelvin scale, graduations are called Kelvins. <br> <br> [<strong>geometry</strong>]&hellip;" data-term-url="/en/glossary/view/degree/8535">degrees</mark> north or south), while temperature zones are further (defined as between the Tropic of Cancer and Arctic Circle, or Tropic of Capricorn and Antarctic Circle). Since Humboldt’s <mark class="term" data-term="work" data-term-def="A process that occurs when a force acts over a distance, as when an object is moved. Work equals the multiple&hellip;" data-term-url="/en/glossary/view/work/1502">work</mark>, the LDG has become an accepted part of the scientific understanding of biodiversity. <mark id="ngss-114" class="ngss">The LDG established that biodiversity is concentrated near the equator (that is, at lower, tropical latitudes). This is true whether you count <mark class="term" data-term="species" data-term-def="1. In biological classifications, it is the lowest and most basic unit of the Linnaean taxonomic hierarchy (although it is also&hellip;" data-term-url="/en/glossary/view/species/893">species</mark> on land or in water, and it is true across all kinds of life - from single-celled <mark class="term" data-term="organism" data-term-def="Any connected living system, such as an animal, plant, fungus, or bacterium. Organisms may be composed of a single cell or&hellip;" data-term-url="/en/glossary/view/organism/2171">organisms</mark> to plants and animals. Tropical rainforests house more than half of the world’s known species, despite covering just seven percent of Earth’s land <mark class="term" data-term="surface" data-term-def="The outside or external part; the topside face of something." data-term-url="/en/glossary/view/surface/8275">surface</mark> (Primack and Morrison, 2013). Judging from <mark class="term" data-term="fossil" data-term-def="The preserved impression or remains of an animal or plant whose living tissue has been replaced by minerals." data-term-url="/en/glossary/view/fossil/8558">fossils</mark>, the LDG is a pervasive pattern of life on Earth. In fact, fossil <mark class="term" data-term="evidence" data-term-def="Support for an idea, opinion, or hypothesis." data-term-url="/en/glossary/view/evidence/8243">evidence</mark> suggests it has existed for 270 million years or more.</mark></p> <p>But the underlying question remains: <em>Why</em> do the tropics have higher biodiversity? Many <mark class="term" data-term="hypothesis" data-term-url="/en/glossary/view/hypothesis" data-term-def="From the Greek word <em>hypothesis</em> meaning assumption or the basis of an argument, a hypothesis is a proposal intended to explain&hellip;">hypotheses</mark> have been proposed, and scientists are still grappling with this key question. For example, in wondering what drives the LDG pattern, <mark id="ngss-115" class="ngss">Chinese geobiologist Haijun Song and colleagues mapped <mark class="term" data-term="latitude" data-term-def="the angular distance of a place north or south of the Earth’s equator, expressed in degrees, minutes and seconds." data-term-url="/en/glossary/view/latitude/12930">latitudes</mark> of more than 50,000 marine fossils described in a database. They identified a 5-million-year <mark class="term" data-term="period" data-term-def="A row of elements in the periodic table." data-term-url="/en/glossary/view/period/8565">period</mark> with no LDG beginning about 252 million years ago. During this period, levels of biodiversity were similar from the poles to the equator. Song attributes the pattern to intense global warming −a greenhouse interval −that overheated the tropics and forced more animals poleward (Song et al., 2020).</mark></p> <p>Song’s results support a <mark class="term" data-term="hypothesis" data-term-def="From the Greek word <em>hypothesis</em> meaning assumption or the basis of an argument, a hypothesis is a proposal intended to explain&hellip;" data-term-url="/en/glossary/view/hypothesis/3727">hypothesis</mark> that <mark class="term" data-term="heat" data-term-def="A measure of the total internal energy of a substance that can be increased or decreased when objects with different temperatures&hellip;" data-term-url="/en/glossary/view/heat/1506">heat</mark> drives the LDG.</p></section> <section id="toc2_3"><h3>Hypothesis 1: <mark class="term" data-term="light" data-term-def="A form of electromagnetic radiation. Visible light is that associated with stimulating the organs of sight, which for normal human&hellip;" data-term-url="/en/glossary/view/light/1498">Light</mark> and heat</h3><p>As early as the 1960s, scientists recognized that tropical <mark class="term" data-term="ecosystem" data-term-def="The complex of a community of organisms and its environment, functioning as a unit." data-term-url="/en/glossary/view/ecosystem/2174">ecosystems</mark> cycle <mark class="term" data-term="nutrient" data-term-def="A chemical substance (e.g., minerals, vitamins, proteins) that is needed by an organism to survive and grow. See also: macronutrient and micronutrient." data-term-url="/en/glossary/view/nutrient/7058">nutrients</mark> quickly than temperate ecosystems, i.e., nutrients like nitrogen move through the tropical <mark class="term" data-term="environment" data-term-def="The conditions that surround and affect an organism." data-term-url="/en/glossary/view/environment/8270">environment</mark> faster, demonstrated by various studies (Vitousek and Sanford, 1986). <mark id="ngss-116" class="ngss">Nutrient cycling requires <mark class="term" data-term="energy" data-term-def="An abstract property defined as the capacity to do work. The basic forms of energy include chemical, electrical, mechanical, nuclear, and&hellip;" data-term-url="/en/glossary/view/energy/1497">energy</mark>, which comes from sunlight (see modules <a href="https://www.visionlearning.com/en/library/Earth-Science/6/The-Carbon-Cycle/95" target="_blank" rel="noopener">The Carbon Cycle</a>, <a href="https://www.visionlearning.com/en/library/Earth-Science/6/The-Nitrogen-Cycle/98" target="_blank" rel="noopener">The Nitrogen Cycle</a>, and <a href="https://www.visionlearning.com/en/library/Earth-Science/6/The-Phosphorus-Cycle/197" target="_blank" rel="noopener">The Phosphorus Cycle</a>). More year-round sunlight near the equator <mark class="term" data-term="mean" data-term-def="In statistics, mean commonly refers to the arithmetic mean, also called the average, which is one measure of the mid-point of&hellip;" data-term-url="/en/glossary/view/mean/4221">means</mark> more energy supply for plants to take up nutrients and grow. Plants are at the <mark class="term" data-term="base" data-term-def="Generally, a substance that reacts with acids to form a salt, several different definitions of bases have been proposed by different&hellip;" data-term-url="/en/glossary/view/base/1574">base</mark> of food webs (the connection of all food chains in a single ecosystem), making their food through <mark class="term" data-term="photosynthesis" data-term-def="Formation of carbohydrates from carbon dioxide and a source of hydrogen (as water) in the chlorophyll-containing tissues of plants exposed to light." data-term-url="/en/glossary/view/photosynthesis/2194">photosynthesis</mark>. As a result, their productivity is essential to supporting other <mark class="term" data-term="organism" data-term-def="Any connected living system, such as an animal, plant, fungus, or bacterium. Organisms may be composed of a single cell or&hellip;" data-term-url="/en/glossary/view/organism/2171">organisms</mark>; this is also known as <em>primary productivity.</em></mark></p> <p>Primary productivity is measured in various ways, such as calculating total plant <mark class="term" data-term="biomass" data-term-def="The combined mass of living or once-living organisms in a given area." data-term-url="/en/glossary/view/biomass/2175">biomass</mark> or measuring the carbon that plants incorporate from photosynthesis. <mark id="ngss-117" class="ngss">Figure 4 shows the biomass of plants in different types of ecosystems. What do you notice about the biomass in tropical ecosystems (starting at the left side of the graphic) compared to other ecosystems?</mark></p> <div class="figure"> <figure> <button class="lightbox-button lightbox-button--icon" data-lightbox=""> <img src="/img/library/modules/mid276/Image/VLObject-12394-22052311052658.jpg" alt="Figure 4: Graphic showing the relative amount of carbon stored in plant biomass across ecosystems. USDA Forest Service based on data from Scharlemann et al. (2014)." /> </button> <figcaption> <p><strong>Figure 4:</strong> Graphic showing the relative amount of carbon stored in plant biomass across ecosystems. USDA Forest Service based on data from Scharlemann et al. (2014).</p> <span class="credit">image ©Public Domain</span> </figcaption> </figure> </div> <p>Measures of primary productivity show that it is about twice as high in the tropics as elsewhere. And productivity is not just about the sunlight available for <mark class="term" data-term="photosynthesis" data-term-def="Formation of carbohydrates from carbon dioxide and a source of hydrogen (as water) in the chlorophyll-containing tissues of plants exposed to light." data-term-url="/en/glossary/view/photosynthesis/2194">photosynthesis</mark>. With more sunlight comes <mark class="term" data-term="heat" data-term-def="A measure of the total internal energy of a substance that can be increased or decreased when objects with different temperatures&hellip;" data-term-url="/en/glossary/view/heat/1506">heat</mark>, so <mark class="term" data-term="climate" data-term-def="Climate describes the average and patterns of a particular area’s weather over time. Climate includes such elements as temperature, precipitation, humidity,&hellip;" data-term-url="/en/glossary/view/climate/9334">climates</mark> near the equator are hotter. According to <mark class="term" data-term="kinetic" data-term-def="Relating to the motion of objects." data-term-url="/en/glossary/view/kinetic/8681">Kinetic</mark> Molecular <mark class="term" data-term="theory" data-term-def="A scientific theory is an explanation inferred from multiple lines of evidence for some broad aspect of the natural world and&hellip;" data-term-url="/en/glossary/view/theory/4854">Theory</mark>, <mark class="term" data-term="atom" data-term-def="The smallest unit of an element that retains the chemical properties of the element. Atoms can exist alone or in&hellip;" data-term-url="/en/glossary/view/atom/1509">atoms</mark> and <mark class="term" data-term="molecule" data-term-def="A particle formed by the chemical bonding of two or more atoms. The molecule is the smallest particle of a&hellip;" data-term-url="/en/glossary/view/molecule/1518">molecules</mark> are in <mark class="term" data-term="constant" data-term-def="In mathematics, a quantity that has a fixed value; something that does not vary." data-term-url="/en/glossary/view/constant/8557">constant</mark> motion and move faster when they are warmer (see our <a href="https://www.visionlearning.com/en/library/Chemistry/1/Kinetic-Molecular-Theory/251" target="_blank" rel="noopener">Kinetic-Molecular Theory module</a>). <mark id="ngss-118" class="ngss">When molecules have more <mark class="term" data-term="energy" data-term-def="An abstract property defined as the capacity to do work. The basic forms of energy include chemical, electrical, mechanical, nuclear, and&hellip;" data-term-url="/en/glossary/view/energy/1497">energy</mark>, the chemical processes that affect biological processes, like those regulating growth and reproduction, also go faster. This helps explain the high plant productivity of the tropics (University of Southern California, 2008).</mark></p> <p><mark id="ngss-119" class="ngss">This speeding up of tropical <mark class="term" data-term="ecosystem" data-term-def="The complex of a community of organisms and its environment, functioning as a unit." data-term-url="/en/glossary/view/ecosystem/2174">ecosystem</mark> processes may also cause the quicker <mark class="term" data-term="evolution" data-term-def="Change in the gene pool of a population from generation to generation by such processes as mutation, natural selection, and genetic drift." data-term-url="/en/glossary/view/evolution/5284">evolution</mark> of new <mark class="term" data-term="species" data-term-def="1. In biological classifications, it is the lowest and most basic unit of the Linnaean taxonomic hierarchy (although it is also&hellip;" data-term-url="/en/glossary/view/species/893">species</mark>. Studies have found that the <mark class="term" data-term="DNA" data-term-def="Deoxyribonucleic acid. A double-stranded nucleic acid containing the sugar 2-deoxy-D-ribose. A constituent of cellular nuclear material responsible for encoding&hellip;" data-term-url="/en/glossary/view/DNA/1604">DNA</mark> molecules making up <mark class="term" data-term="gene" data-term-def="Material (usually DNA) that is inherited from a parent and which encodes for a cellular component important for some cellular function." data-term-url="/en/glossary/view/gene/3294">genes</mark> evolve faster in the tropics. Changes in DNA may ultimately result in new species (called “speciation”), which adds to <mark class="term" data-term="biodiversity" data-term-def="The variety and abundance of life and its ecological context, including the different kinds of organisms, the numbers of species, the&hellip;" data-term-url="/en/glossary/view/biodiversity/875">biodiversity</mark>. Some scientists, therefore, call the tropics a “cradle” for biodiversity (Jablonski et al. 2006).</mark></p> <p><mark id="ngss-120" class="ngss">So, if conditions in the tropics speed up <mark class="term" data-term="nutrient" data-term-def="A chemical substance (e.g., minerals, vitamins, proteins) that is needed by an organism to survive and grow. See also: macronutrient and micronutrient." data-term-url="/en/glossary/view/nutrient/7058">nutrient</mark> cycling, productivity, and evolution, the <mark class="term" data-term="outcome" data-term-def="Result." data-term-url="/en/glossary/view/outcome/8247">outcome</mark> is more species diversity. But, even if we can explain why more species arise in the tropics, why don’t they <mark class="term" data-term="spread" data-term-def="The variation within a dataset; the measure of how much individual values in a dataset differ from the mean, or average." data-term-url="/en/glossary/view/spread/8761">spread</mark> out into other areas?</mark></p></section> <section id="toc2_4"><h3>Hypothesis 2: Out of the tropics</h3><p>Biologists propose that environmental conditions keep <mark class="term" data-term="species" data-term-def="1. In biological classifications, it is the lowest and most basic unit of the Linnaean taxonomic hierarchy (although it is also&hellip;" data-term-url="/en/glossary/view/species/893">species</mark> from spreading out of the tropics. Many species have a long <mark class="term" data-term="evolutionary history" data-term-def="Natural selection influenced animal behavioral characteristics over time." data-term-url="/en/glossary/view/evolutionary+history/13149">evolutionary history</mark> of living in the tropics. If they are adapted to a warm, humid <mark class="term" data-term="climate" data-term-def="Climate describes the average and patterns of a particular area’s weather over time. Climate includes such elements as temperature, precipitation, humidity,&hellip;" data-term-url="/en/glossary/view/climate/9334">climate</mark>, they might not tolerate other conditions (see our <a href="https://www.visionlearning.com/en/library/Biology/2/Adaptation/68" target="_blank" rel="noopener">Adaptation: The Case of Penguins module</a>). The <mark class="term" data-term="outcome" data-term-def="Result." data-term-url="/en/glossary/view/outcome/8247">outcome</mark> is a wealth of <mark class="term" data-term="biodiversity" data-term-def="The variety and abundance of life and its ecological context, including the different kinds of organisms, the numbers of species, the&hellip;" data-term-url="/en/glossary/view/biodiversity/875">biodiversity</mark> in the tropics that has adapted to tropical conditions and cannot live elsewhere (Brown, 2014).</p> <p>Studies of how <mark class="term" data-term="organism" data-term-def="Any connected living system, such as an animal, plant, fungus, or bacterium. Organisms may be composed of a single cell or&hellip;" data-term-url="/en/glossary/view/organism/2171">organisms</mark> are distributed provide <mark class="term" data-term="evidence" data-term-def="Support for an idea, opinion, or hypothesis." data-term-url="/en/glossary/view/evidence/8243">evidence</mark> that supports this <mark class="term" data-term="hypothesis" data-term-def="From the Greek word <em>hypothesis</em> meaning assumption or the basis of an argument, a hypothesis is a proposal intended to explain&hellip;" data-term-url="/en/glossary/view/hypothesis/3727">hypothesis</mark>. For example, <mark id="ngss-121" class="ngss">Iranian biologist Sana Sharifian studies the geographic distribution of mangrove crabs. She wondered whether she could predict where different species live based on environmental factors like sea <mark class="term" data-term="surface" data-term-def="The outside or external part; the topside face of something." data-term-url="/en/glossary/view/surface/8275">surface</mark> temperature and other ocean conditions. Using more than 8,000 <mark class="term" data-term="record" data-term-def="A written account or description. <br> <b>[verb]</b> To write an account or description." data-term-url="/en/glossary/view/record/8239">records</mark> of where mangrove crabs have been found, Sharifian calculated species richness and plotted it by <mark class="term" data-term="latitude" data-term-def="the angular distance of a place north or south of the Earth’s equator, expressed in degrees, minutes and seconds." data-term-url="/en/glossary/view/latitude/12930">latitude</mark> (Sharifian et al., 2020). In Sharifian’s graphic (Figure 5), blue dots represent the number of mangrove crab species, while colored bands represent temperature.</mark> Would you say that sea surface temperature is a good predictor of where species of mangrove crabs live?</p> <div class="figure"> <figure> <button class="lightbox-button lightbox-button--icon" data-lightbox=""> <img src="/img/library/modules/mid276/Image/VLObject-12395-22052311052956.jpg" alt="Figure 5: Map of numbers of species of mangrove crabs (blue dots) against sea surface temperatures (colored bands)." /> </button> <figcaption> <p><strong>Figure 5:</strong> Map of numbers of species of mangrove crabs (blue dots) against sea surface temperatures (colored bands).</p> <span class="credit">image ©Sharifian, S., Kamrani, E. Saeedi, H. (2020)</span> </figcaption> </figure> </div> <p>Mapping <mark class="term" data-term="species" data-term-def="1. In biological classifications, it is the lowest and most basic unit of the Linnaean taxonomic hierarchy (although it is also&hellip;" data-term-url="/en/glossary/view/species/893">species</mark> richness by <mark class="term" data-term="latitude" data-term-def="the angular distance of a place north or south of the Earth’s equator, expressed in degrees, minutes and seconds." data-term-url="/en/glossary/view/latitude/12930">latitude</mark> revealed that the highest mangrove crab diversity is in tropical waters, especially in the Indo West-Pacific, indicating that temperature is the best predictor of where they live.</p> <p><mark id="ngss-122" class="ngss">Species accumulating in the tropics eventually <mark class="term" data-term="spread" data-term-def="The variation within a dataset; the measure of how much individual values in a dataset differ from the mean, or average." data-term-url="/en/glossary/view/spread/8761">spread</mark> into higher latitudes as they evolve <mark class="term" data-term="adaptation" data-term-def="A change that allows an organism to function better in a particular environment." data-term-url="/en/glossary/view/adaptation/8284">adaptations</mark> for cooler <mark class="term" data-term="climate" data-term-def="Climate describes the average and patterns of a particular area’s weather over time. Climate includes such elements as temperature, precipitation, humidity,&hellip;" data-term-url="/en/glossary/view/climate/9334">climates</mark>.</mark> <mark id="ngss-123" class="ngss">For example, American geophysicist Dave Jablonski examined <mark class="term" data-term="fossil" data-term-def="The preserved impression or remains of an animal or plant whose living tissue has been replaced by minerals." data-term-url="/en/glossary/view/fossil/8558">fossils</mark> of marine bivalves (two-shelled clams, oysters, etc.) from the past 11 million years and plotted where and when each species originated. He found that the tropics have been “an engine of global <mark class="term" data-term="biodiversity" data-term-def="The variety and abundance of life and its ecological context, including the different kinds of organisms, the numbers of species, the&hellip;" data-term-url="/en/glossary/view/biodiversity/875">biodiversity</mark>,” producing most of the new bivalve species, which then expanded their ranges towards the poles over thousands of years. But, even as their ranges expanded, nearly all of them continued to live in the tropics.</mark> In Jablonski’s view, this makes the tropics both a “cradle” (where species arise) and a “museum” (where species remain) for biodiversity (Jablonski et al., 2006).</mark></mark></p> <p>Besides the stable, warm conditions of the tropics, their high biodiversity may also relate to their complexity.</p></section> <section id="toc2_5"><h3>Hypothesis 3: Heterogeneity</h3><p>Because they support high plant diversity, tropical areas have more variety of <mark class="term" data-term="habitat" data-term-def="The place or type of environment where a wild plant, animal, or other organism naturally lives or grows." data-term-url="/en/glossary/view/habitat/5593">habitats</mark> (heterogeneity). A tropical forest is made up of multiple layers of plant <mark class="term" data-term="species" data-term-def="1. In biological classifications, it is the lowest and most basic unit of the Linnaean taxonomic hierarchy (although it is also&hellip;" data-term-url="/en/glossary/view/species/893">species</mark> that differ as you move from the ground to the tree canopy. <mark id="ngss-124" class="ngss">Within an <mark class="term" data-term="ecosystem" data-term-def="The complex of a community of organisms and its environment, functioning as a unit." data-term-url="/en/glossary/view/ecosystem/2174">ecosystem</mark>, each <mark class="term" data-term="organism" data-term-def="Any connected living system, such as an animal, plant, fungus, or bacterium. Organisms may be composed of a single cell or&hellip;" data-term-url="/en/glossary/view/organism/2171">organism</mark> has a habitat niche, defined by the resources it uses. This layering may support high <mark class="term" data-term="biodiversity" data-term-def="The variety and abundance of life and its ecological context, including the different kinds of organisms, the numbers of species, the&hellip;" data-term-url="/en/glossary/view/biodiversity/875">biodiversity</mark> by providing more unique niches for species.</mark></p> <p>For example, <mark id="ngss-125" class="ngss">American biologist Jonathan Huie is one of a <mark class="term" data-term="group" data-term-def="A column of elements in the periodic table." data-term-url="/en/glossary/view/group/8566">group</mark> of biologists working to understand how animals in the tropics reduce competition by occupying different <mark class="term" data-term="habitat" data-term-url="/en/glossary/view/habitat" data-term-def="The place or type of environment where a wild plant, animal, or other organism naturally lives or grows.">habitats</mark>. As a graduate student, he examined the features of tropical anole lizards and categorized them according to their lifestyle—how they use the habitats (Huie et al. 2021).</mark></p> <p><mark id="ngss-126" class="ngss">The diagram (Figure 6) shows where you find species of anole lizards in a tropical forest ecosystem. What might you conclude about how they share the habitat?</mark></p> <div class="figure"> <figure> <button class="lightbox-button lightbox-button--icon" data-lightbox=""> <img src="/img/library/modules/mid276/Image/VLObject-12396-22052311053531.jpg" alt="Figure 6: Diagram showing where different species of anole lizard are found in tropical forests." /> </button> <figcaption> <p><strong>Figure 6:</strong> Diagram showing where different species of anole lizard are found in tropical forests.</p> <span class="credit">image ©CC BY: Eva Horne, modified from Williams et al., 1983</span> </figcaption> </figure> </div> <p><mark id="ngss-127" class="ngss">On both islands and mainland South America, scientists like Huie find that anole lizard <mark class="term" data-term="species" data-term-def="1. In biological classifications, it is the lowest and most basic unit of the Linnaean taxonomic hierarchy (although it is also&hellip;" data-term-url="/en/glossary/view/species/893">species</mark> sort out into lifestyles of ground, grass-bush, trunk-ground, trunk, trunk-crown, twig, and crown-giant. By using different parts of the <mark class="term" data-term="habitat" data-term-def="The place or type of environment where a wild plant, animal, or other organism naturally lives or grows." data-term-url="/en/glossary/view/habitat/5593">habitat</mark>, species rely on unique sets of resources. And the more heterogeneous a habitat, the more species can share it, that is, the more <mark class="term" data-term="biodiversity" data-term-def="The variety and abundance of life and its ecological context, including the different kinds of organisms, the numbers of species, the&hellip;" data-term-url="/en/glossary/view/biodiversity/875">biodiversity</mark>.</mark></p> <p>Scientists still <mark class="term" data-term="debate" data-term-def="A reasoned discussion of opposing points in an argument." data-term-url="/en/glossary/view/debate/8242">debate</mark> whether the high biodiversity of the tropics and the Latitudinal Diversity Gradient as you head towards the poles is due to <mark class="term" data-term="light" data-term-def="A form of electromagnetic radiation. Visible light is that associated with stimulating the organs of sight, which for normal human&hellip;" data-term-url="/en/glossary/view/light/1498">light</mark>, temperature, stability, heterogeneity, or other factors. Explaining the LDG is a challenge that involves many scientific fields. Biologists, ecologists, geologists, and other specialists continue to gather <mark class="term" data-term="evidence" data-term-def="Support for an idea, opinion, or hypothesis." data-term-url="/en/glossary/view/evidence/8243">evidence</mark>.</p> <p>Find your location on a map and note your <mark class="term" data-term="latitude" data-term-def="the angular distance of a place north or south of the Earth’s equator, expressed in degrees, minutes and seconds." data-term-url="/en/glossary/view/latitude/12930">latitude</mark>. Does latitude explain the biodiversity around you? Think about both the count you did outside where you live and the life you see in your region. Note what else (besides latitude) may help explain the pattern of your local biodiversity.</p> <div class="comprehension-checkpoint margin-y-4"> <h6 class="comprehension-checkpoint__header"> <span> <span class="icon icon-question"></span> </span> Comprehension Checkpoint </h6> <form class="" name="cc12376"> <div class="form-entry"> <div class="form-entry__field"> <span class="form-entry__field__label">Factors that might explain why biodiversity changes with latitude include...</span> <div class="form-entry__option"> <div class="form-entry__option__radio" data-answer="incorrect"> <label> <input id="q1-12376-0-option-a" name="quiz-option-12376" type="radio" value="complexity and fossils." > <span class="option__label"> <span class="screen-reader-only">a.</span> complexity and fossils. </span> </label> <span class="quiz__response" id="response-12376-0"> <strong>Incorrect.</strong> </span> </div> <div class="form-entry__option__radio" data-answer="incorrect"> <label> <input id="q1-12376-1-option-b" name="quiz-option-12376" type="radio" value="fossils and climate." > <span class="option__label"> <span class="screen-reader-only">b.</span> fossils and climate. </span> </label> <span class="quiz__response" id="response-12376-1"> <strong>Incorrect.</strong> </span> </div> <div class="form-entry__option__radio" data-answer="correct"> <label> <input id="q1-12376-2-option-c" name="quiz-option-12376" type="radio" value="climate and complexity." > <span class="option__label"> <span class="screen-reader-only">c.</span> climate and complexity. </span> </label> <span class="quiz__response" id="response-12376-2"> <strong>Correct!</strong> </span> </div> <div class="form-entry__option__radio" data-answer="incorrect"> <label> <input id="q1-12376-5-option-" name="quiz-option-12376" type="radio" value="clima y complejidad." > <span class="option__label"> <span class="screen-reader-only">.</span> clima y complejidad. </span> </label> <span class="quiz__response" id="response-12376-5"> <strong>Incorrect.</strong> </span> </div> </div> </div> </div> </form> </div> </section> <section id="toc_6"> <h2>Biodiversity on islands</h2> <p>“Islands are tumultuous places; raised from the oceans or divided from continents, they undergo change at a pace faster than most other <mark class="term" data-term="biome" data-term-def="A large, distinct biological community characterized by vegetation and wildlife adapted to particular environmental conditions, such as climate and soil type.&hellip;" data-term-url="/en/glossary/view/biome/5606">biomes</mark>. The <mark class="term" data-term="species" data-term-def="1. In biological classifications, it is the lowest and most basic unit of the Linnaean taxonomic hierarchy (although it is also&hellip;" data-term-url="/en/glossary/view/species/893">species</mark> that colonize and persist upon islands react and adapt to this <mark class="term" data-term="constant" data-term-def="In mathematics, a quantity that has a fixed value; something that does not vary." data-term-url="/en/glossary/view/constant/8557">constant</mark> change.” <p align="right">– James C. Russell, 2019</p></p> <p>Islands, as fragments of land surrounded by the ocean, are a special case when it comes to <mark class="term" data-term="biodiversity" data-term-def="The variety and abundance of life and its ecological context, including the different kinds of organisms, the numbers of species, the&hellip;" data-term-url="/en/glossary/view/biodiversity/875">biodiversity</mark>. <mark id="ngss-128" class="ngss">R. H. MacArthur and E. O. Wilson (1967) proposed the <mark class="term" data-term="theory" data-term-def="A scientific theory is an explanation inferred from multiple lines of evidence for some broad aspect of the natural world and&hellip;" data-term-url="/en/glossary/view/theory/4854">Theory</mark> of Island Biogeography, which states that biodiversity should increase with island area and closeness to other landmasses. Since islands are separated by ocean waters and not all <mark class="term" data-term="species" data-term-def="1. In biological classifications, it is the lowest and most basic unit of the Linnaean taxonomic hierarchy (although it is also&hellip;" data-term-url="/en/glossary/view/species/893">species</mark> can fly, float or swim across, islands that are more isolated islands should have fewer species. And smaller islands should have fewer species because they offer a lower diversity of resources. Thus, you would expect the smallest, most isolated islands to have the lowest biodiversity.</mark></p> <p>The predictions of Island Biogeography Theory have proved correct in most circumstances but fail to explain the whole picture. <mark id="ngss-129" class="ngss">For example, consider the Hawaiian Islands. Hawai’i is the biggest island in the archipelago (a collection of islands), and all the Hawaiian Islands are really far (more than 9,000 km or 5,600 miles) from mainland North America. Based on Island Biogeography Theory, what would you predict about the biodiversity on Hawai’i compared to its increasingly smaller neighbors of Maui, Oahu, and Kauai? Do <mark class="term" data-term="data" data-term-def="(plural form of <b>datum</b>) A collection of pieces of information, generally taking the form of numbers, text, bits, or facts, that&hellip;" data-term-url="/en/glossary/view/data/3729">data</mark> on island size plotted against species richness support your prediction (Figure 7)?</mark></p> <div class="figure"> <figure> <button class="lightbox-button lightbox-button--icon" data-lightbox=""> <img src="/img/library/modules/mid276/Image/VLObject-12397-22052311054136.jpg" alt="Figure 7: Species richness plotted against size for four of the islands in the Hawaiian archipelago. Adapted from Craven at al. 2019." /> </button> <figcaption> <p><strong>Figure 7:</strong> Species richness plotted against size for four of the islands in the Hawaiian archipelago. Adapted from Craven at al. 2019.</p> <span class="credit">image ©Craven et al., 2019</span> </figcaption> </figure> </div> <p><mark id="ngss-130" class="ngss">Island Biogeography <mark class="term" data-term="theory" data-term-def="A scientific theory is an explanation inferred from multiple lines of evidence for some broad aspect of the natural world and&hellip;" data-term-url="/en/glossary/view/theory/4854">Theory</mark> predicts that the biggest island, Hawai’I, as the highest <mark class="term" data-term="biodiversity" data-term-def="The variety and abundance of life and its ecological context, including the different kinds of organisms, the numbers of species, the&hellip;" data-term-url="/en/glossary/view/biodiversity/875">biodiversity</mark>. In fact, Hawai’i has the lowest biodiversity, with <mark class="term" data-term="species" data-term-def="1. In biological classifications, it is the lowest and most basic unit of the Linnaean taxonomic hierarchy (although it is also&hellip;" data-term-url="/en/glossary/view/species/893">species</mark> richness increasing as islands get smaller. While Island Biogeography Theory is accurate in many circumstances, scientists are coming to understand other important factors.</mark> Estonian ecologist <mark id="ngss-131" class="ngss">Madli Jõks modeled the expected species richness on <mark class="term" data-term="group" data-term-def="A column of elements in the periodic table." data-term-url="/en/glossary/view/group/8566">groups</mark> of islands and found factors besides island size to be important (Jõks and Pärtel, 2018). In the case of Hawai’I, island age comes into play. The smallest islands are older, having formed earlier from volcanoes building up from the ocean floor. Their higher biodiversity can be explained by more time for species to colonize them.</mark></p> <div class="comprehension-checkpoint margin-y-4"> <h6 class="comprehension-checkpoint__header"> <span> <span class="icon icon-question"></span> </span> Comprehension Checkpoint </h6> <form class="" name="cc12380"> <div class="form-entry"> <div class="form-entry__field"> <span class="form-entry__field__label">Island Biogeography Theory has proved to be...</span> <div class="form-entry__option"> <div class="form-entry__option__radio" data-answer="incorrect"> <label> <input id="q1-12380-0-option-a" name="quiz-option-12380" type="radio" value="false based on new data." > <span class="option__label"> <span class="screen-reader-only">a.</span> false based on new data. </span> </label> <span class="quiz__response" id="response-12380-0"> <strong>Incorrect.</strong> </span> </div> <div class="form-entry__option__radio" data-answer="correct"> <label> <input id="q1-12380-1-option-b" name="quiz-option-12380" type="radio" value="mainly true with some exceptions." > <span class="option__label"> <span class="screen-reader-only">b.</span> mainly true with some exceptions. </span> </label> <span class="quiz__response" id="response-12380-1"> <strong>Correct!</strong> </span> </div> </div> </div> </div> </form> </div> </section> <section id="toc_7"> <h2>Value of biodiversity</h2> <p>"Biodiversity is an essential heritage for all humankind...Stopping its loss, and guaranteeing the continued functioning of the earth's ecosystems− both marine and terrestrial− should be a high priority for everyone." <p align="right">– United Nations Secretary General Kofi Annan, 2003</p></p> <p>Why do we care about biodiversity?</p> <p>Losing <mark class="term" data-term="species" data-term-def="1. In biological classifications, it is the lowest and most basic unit of the Linnaean taxonomic hierarchy (although it is also&hellip;" data-term-url="/en/glossary/view/species/893">species</mark> <mark class="term" data-term="mean" data-term-def="In statistics, mean commonly refers to the arithmetic mean, also called the average, which is one measure of the mid-point of&hellip;" data-term-url="/en/glossary/view/mean/4221">means</mark> losing the interactions that they have with other species, which can lead to a cascade of species losses (Valiente-Banuet et al., 2014). <mark id="ngss-132" class="ngss">For example, local <mark class="term" data-term="extinction" data-term-def="The complete and permanent loss of all individuals of a species of organism." data-term-url="/en/glossary/view/extinction/5615">extinctions</mark> of wolves in Yellowstone National Park resulted in fewer predators for elk <mark class="term" data-term="population" data-term-def="In biology, the population is all individuals of a certain kind of plant or animal that live in a particular habitat.&hellip;" data-term-url="/en/glossary/view/population/8283">populations</mark>, causing them to grow. The growing elk populations reduced the streamside willows they graze on. As a result, beavers no longer had the slow-moving water around willows that they rely on and disappeared from Yellowstone. So, the loss of a single species may have far-reaching effects on an <mark class="term" data-term="ecosystem" data-term-def="The complex of a community of organisms and its environment, functioning as a unit." data-term-url="/en/glossary/view/ecosystem/2174">ecosystem</mark>. Supply of water, formation of <mark class="term" data-term="soil" data-term-def="The loose top layer of Earth’s surface where plants grow, made up of particles of rocks, minerals, and organic material." data-term-url="/en/glossary/view/soil/8563">soil</mark>, cycling of <mark class="term" data-term="mineral" data-term-def="A naturally formed, inorganic solid with a specific chemical composition and characteristic crystal structure. Examples of minerals include quartz (SiO<sub>2</sub>), salt&hellip;" data-term-url="/en/glossary/view/mineral/2978">minerals</mark>, and maintenance of <mark class="term" data-term="climate" data-term-def="Climate describes the average and patterns of a particular area’s weather over time. Climate includes such elements as temperature, precipitation, humidity,&hellip;" data-term-url="/en/glossary/view/climate/9334">climate</mark> are among other ecosystem services that may be disrupted.</mark></p> <p><mark id="ngss-133" class="ngss">For example, Brazilian ecologist Julia Astegiano finds that as <mark class="term" data-term="habitat" data-term-def="The place or type of environment where a wild plant, animal, or other organism naturally lives or grows." data-term-url="/en/glossary/view/habitat/5593">habitats</mark> get degraded, the diversity of pollinators like bees goes down. The loss of pollinator diversity leads to shifts in plant diversity. This can result in “community collapse,” where just a fraction of the former species survives (Astegiano et al., 2015). Due to the loss of insects, plants, and other species, agricultural and urban areas tend to have lower <mark class="term" data-term="biodiversity" data-term-def="The variety and abundance of life and its ecological context, including the different kinds of organisms, the numbers of species, the&hellip;" data-term-url="/en/glossary/view/biodiversity/875">biodiversity</mark> than wild areas (Rogan and Lacher, 2018).</mark></p> <p>The significance of biodiversity was first acknowledged broadly when Ghanaian Kofi Annan, then U.N. Secretary-General, called for a Millennium Ecosystem Assessment in 2005. The assessment detailed the effects of ecosystem change on humans and concluded that biodiversity and our human well-being are inextricably linked (Millenium Ecosystem Assessment, 2005).</p> <p><mark id="ngss-134" class="ngss">Since then, many have invested in studying and conserving the complex living <mark class="term" data-term="system" data-term-def="A group of interacting, interrelated or interdependent components that form a complex whole. The size of the system is defined for&hellip;" data-term-url="/en/glossary/view/system/3904">system</mark> that is biodiversity. As we continue to learn more about what determines biodiversity, we become better equipped to manage it. But sustainably managing the diversity of life does not mean there will be no changes. Rather, it calls for an intentional approach to tracking and managing change.</mark></p> </div> </section> <hr class="border-color-dark" /> <footer class="module__footer"> <p class="citation"> <em> Devin Reese, PhD. “Biodiversity I” Visionlearning Vol. BIO-5 (6), 2022. </em> </p>  <div class="title-list" id="refs" name="refs"> <p class="h6 title-list__title"> References </p> <ul class="title-list__list"> <li><p>Astegiano, J., Guimarães, P. R., Cheptou, P.-O., Vidal, M. M., Mandai, C. Y., Ashworth, L., & Massol, F. (2015). Persistence of plants and pollinators in the face of habitat loss. <em>Advances in Ecological Research,</em> 201–257. </p></li> <li><p>Brown, James H. "Why are there so many species in the tropics?." <em>Journal of biogeography</em> 41, no. 1 (2014): 8-22.</p></li> <li><p>Bruns, H. Arnold. "Southern corn leaf blight: a story worth retelling." <em>Agronomy Journal</em> 109, no. 4 (2017): 1218-1224.</p></li> <li><p>Casselman, Anne. "Strange but true: The largest organism on Earth is a fungus." <em>Scientific American</em> 4 (2007).</p></li> <li><p>Cofrin Center for Biodiversity. <em>Biodiversity</em>. University of Wisconsin, Green Bay. https://www.uwgb.edu/biodiversity/about/biodiversity.asp</p></li> <li><p>Convention on Biological Diversity. "Genetic Diversity: The Hidden Secret of Life." (2021) https://www.cbd.int/article/genetic-diversity-the-hidden-secret-of-life</p></li> <li><p>Convention on Biological Diversity. Article 2. Use of Terms. (2006) https://www.cbd.int/convention/articles/?a=cbd-02</p></li> <li><p>Costello, Mark J., Robert M. May, and Nigel E. Stork. "Can we name Earth's species before they go extinct?." <em>Science</em> 339, no. 6118 (2013): 413-416.</p></li> <li><p>Craven, Dylan, Tiffany M. Knight, Kasey E. Barton, Lalasia Bialic-Murphy, and Jonathan M. Chase. "Dissecting macroecological and macroevolutionary patterns of forest biodiversity across the Hawaiian archipelago." <em>Proceedings of the National Academy of Sciences</em> 116, no. 33 (2019): 16436-16441.</p></li> <li><p>Danielsen, Finn, Per M. Jensen, Neil D. Burgess, Indiana Coronado, Sune Holt, Michael K. Poulsen, Ricardo M. Rueda et al. "Testing focus groups as a tool for connecting indigenous and local knowledge on abundance of natural resources with science‐based land management systems." <em>Conservation Letters</em> 7, no. 4 (2014): 380-389.</p></li> <li><p>Dowle, E. J., M. Morgan-Richards, and S. A. Trewick. "Molecular evolution and the latitudinal biodiversity gradient." <em>Heredity</em> 110, no. 6 (2013): 501-510.</p></li> <li><p>Erwin, Terry L. "Tropical forests: their richness in Coleoptera and other arthropod species." <em>The Coleopterists Bulletin</em> (1982).</p></li> <li><p>Hebert, Paul DN, Alina Cywinska, Shelley L. Ball, and Jeremy R. DeWaard. "Biological identifications through DNA barcodes." <em>Proceedings of the Royal Society of London. Series B: Biological Sciences</em> 270, no. 1512 (2003): 313-321.</li> <li><p>Hughes, A. Randall, Brian D. Inouye, Marc TJ Johnson, Nora Underwood, and Mark Vellend. "Ecological consequences of genetic diversity." <em>Ecology letters</em> 11, no. 6 (2008): 609-623.</p></li> <li><p>Jablonski, David, Kaustuv Roy, and James W. Valentine. "Out of the tropics: evolutionary dynamics of the latitudinal diversity gradient." <em>Science</em> 314, no. 5796 (2006): 102-106.</p></li> <li><p>Jõks, Madli, and Meelis Pärtel. "Plant diversity in Oceanic archipelagos: Realistic patterns emulated by an agent‐based computer simulation." <em>Ecography</em> 42, no. 4 (2019): 740-754.</p></li> <li><p>Jou, W. Min, G. Haegeman, M. Ysebaert, and W. Fiers. "Nucleotide sequence of the gene coding for the bacteriophage MS2 coat protein." <em>Nature</em> 237, no. 5350 (1972): 82-88.</p></li> <li><p>Klein, M. "The First Isothermic World Maps." <em>Worlds Revealed: Geography of Maps.</em> Library of Congress. (2018) https://blogs.loc.gov/maps/2018/04/the-first-isothermic-world-maps/</p></li> <li><p>Lynch, A. "Why is Genetic Diversity Important?" <em>The Fisheries Blog.</em> (2016) https://thefisheriesblog.com/2016/03/21/genetic-diversity/</p></li> <li><p>MacArthur, R. H., and E. O. Wilson. "The Theory of Island Biogeography. MacArthur RH, editor." <em>Monographs in Population Biology.</em> Princeton University Press 10 (1967): 1796430.</p></li> <li><p>Millenium Ecosystem Assessment (2005). United Nations. https://www.millenniumassessment.org/en/index.html</p></li> <li><p>Montgomery, Graham A., Michael W. Belitz, Rob P. Guralnick, and Morgan W. Tingley. "Standards and best practices for monitoring and benchmarking insects." <em>Frontiers in Ecology and Evolution</em> (2021): 513.</p></li> <li><p>Moret, Pierre, Priscilla Muriel, Ricardo Jaramillo, and Olivier Dangles. "Humboldt’s tableau physique revisited." <em>Proceedings of the National Academy of Sciences</em> 116, no. 26 (2019): 12889-12894.</p></li> <li>Morris, P. "Ramari Stewart on Keeping Traditions Alive." <em>New Zealand Geographic</em>. (2020) https://www.nzgeo.com/stories/call-of-the-whales/</li> <li><p>Ødegaard, Frode, Ola H. Diserud, Steinar Engen, and Kaare Aagaard. "The magnitude of local host specificity for phytophagous insects and its implications for estimates of global species richness." <em>Conservation Biology</em> 14, no. 4 (2000): 1182-1186.</p></li> <li><p>Primack, R. B. and Morrison, R. A. (2013). <em>Extinction, Causes of.</em> Encyclopedia of Biodiversity (Second Edition), 401-412. https://www.sciencedirect.com/science/article/pii/B9780123847195000502</p></li> <li><p>Rogan, Jordan E., and Thomas E. Lacher Jr. "Impacts of habitat loss and fragmentation on terrestrial biodiversity." (2018).</p></li> <li><p>Russell, James C., and Christoph Kueffer. "Island biodiversity in the Anthropocene." <em>Annual Review of Environment and Resources</em> 44 (2019): 31-60.</p></li> <li><p>Scharlemann, Jörn PW, Edmund VJ Tanner, Roland Hiederer, and Valerie Kapos. "Global soil carbon: understanding and managing the largest terrestrial carbon pool." <em>Carbon Management</em> 5, no. 1 (2014): 81-91.</p></li> <li><p>Sharifian S, Kamrani E, Saeedi H. <em>Global biodiversity and biogeography of mangrove crabs: Temperature, the key driver of latitudinal gradients of species richness.</em> J Therm Biol. 2020 Aug;92:102692. https://pubmed.ncbi.nlm.nih.gov/32888577/</p></li> <li><p>Sigwart, Julia D., K. D. Bennett, Stewart M. Edie, Luke Mander, Beth Okamura, Kevin Padian, Quentin Wheeler, Judith E. Winston, and Norine W. Yeung. "Measuring biodiversity and extinction—present and past." <em>Integrative and comparative biology</em> 58, no. 6 (2018): 1111-1117.</p></li> <li><p>Song, Haijun, Shan Huang, Enhao Jia, Xu Dai, Paul B. Wignall, and Alexander M. Dunhill. "Flat latitudinal diversity gradient caused by the Permian–Triassic mass extinction." <em>Proceedings of the National Academy of Sciences</em> 117, no. 30 (2020): 17578-17583.</p></li> <li><p>Tallavaara, Miikka, Jussi T. Eronen, and Miska Luoto. "Productivity, biodiversity, and pathogens influence the global hunter-gatherer population density." <em>Proceedings of the National Academy of Sciences </em>115, no. 6 (2018): 1232-1237.</p></li> <li><p>Tauli-Corupuz, V. "Indigenous People are guardians of global biodiversity– but we need protection too." Reuters. (2019).</li> <li><p>United Nations News (2003, 22 May) <em>Annan calls for preservation of world’s biodiversity.</em> UN News: Global perspective Human stories. https://news.un.org/en/story/2003/05/68762-annan-calls-preservation-worlds-biodiversity</p></li> <li><p>University of Southern California. (2008, May 29). Heat, Not Light, May Be Real Engine Driving Biodiversity. <em>ScienceDaily.</em> Retrieved January 29, 2022 from www.sciencedaily.com/releases/2008/05/080527155533.htm</p></li> <li><p>Vitousek, Peter M., and Robert L. Sanford Jr. "Nutrient cycling in moist tropical forest." <em>Annual review of Ecology and Systematics</em> 17, no. 1 (1986): 137-167.</p></li> <li><p>Von Humboldt, A. and Bonpland, A. (1807). <em>Essai sur la géographie des plantes, accompagné d’un tableau physique des régions équinoxiales.</em> Levrault & Schoell, Paris, 1807. https://www.biodiversitylibrary.org/item/37872#page/3/mode/1up</p></li> <li><p>Wallace, Alfred Russel. <em>The Geographical Distribution of Animals: With a Study of the Relations of Living and Extinct Faunas as Elucidating the Past Changes.</em> e-artnow, 2020.</p></li> <li><p>Wilson, Edward O. "The 8 million species we don’t know." <em>The New York Times</em> 3 (2018).</p></li> </ul> </div> </footer> </div>   </div>  <div class="order-1 order-2--lg module__tools"> <div class="narrow margin-x-auto position-sticky-top font-size-md"> <div class="padding-2 border-radius box-shadow-1--lg"> <div class="tabs" role="tablist"> <nav> <button class="button button--icon-label" id="tab-button-in-this-module" aria-label="Table of Contents" aria-controls="tab-panel-module__tools" aria-selected="true" role="tab"> <span class="icon icon-list" aria-hidden="true"></span> <span class="button__text">Contents</span> </button> <button class="button button--icon-label" id="tab-button-toggle-terms" aria-controls="tab-panel-toggle-terms" aria-selected="false" role="tab"> <span class="icon icon-glossary-highlight"></span> <span class="button__text">Glossary Terms</span> </button> <button class="button button--icon-label" id="tab-button-toggle-ngss" aria-controls="tab-panel-toggle-ngss" aria-selected="false" role="tab"> <span class="icon icon-ngss"></span> <span class="button__text">NGSS</span> </button> </nav> <hr class="divider" /> <div class="tabs__panel shown" id="tab-panel-module__tools" aria-labelledby="tab-button-module__tools" role="tabpanel"> <p class="font-weight-bold margin-bottom-1"> Table of Contents </p> <div class="table-of-contents" id="module-toc"> <ul> <li><a href="/en/library/biology/2/biodiversity-i/276#toc_1">What is biodiversity?</a> </li> <li><a href="/en/library/biology/2/biodiversity-i/276#toc_2">Species biodiversity</a> </li> <li> <ul> <li><a href="/en/library/biology/2/biodiversity-i/276#toc2_1">Counting species</a> </li> </ul> </li> <li> <ul> <li><a href="/en/library/biology/2/biodiversity-i/276#toc2_2">Ways of knowing</a> </li> </ul> </li> <li><a href="/en/library/biology/2/biodiversity-i/276#toc_3">Genetic diversity</a> </li> <li><a href="/en/library/biology/2/biodiversity-i/276#toc_4">Ecosystem diversity</a> </li> <li><a href="/en/library/biology/2/biodiversity-i/276#toc_5">Biodiversity and latitude</a> </li> <li> <ul> <li><a href="/en/library/biology/2/biodiversity-i/276#toc2_3">Hypothesis 1: Light and heat</a> </li> </ul> </li> <li> <ul> <li><a href="/en/library/biology/2/biodiversity-i/276#toc2_4">Hypothesis 2: Out of the tropics</a> </li> </ul> </li> <li> <ul> <li><a href="/en/library/biology/2/biodiversity-i/276#toc2_5">Hypothesis 3: Heterogeneity</a> </li> </ul> </li> <li><a href="/en/library/biology/2/biodiversity-i/276#toc_6">Biodiversity on islands</a> </li> <li><a href="/en/library/biology/2/biodiversity-i/276#toc_7">Value of biodiversity</a> </li> </ul> </div> </div>   <div class="tabs__panel" id="tab-panel-toggle-terms" aria-labelledby="tab-button-toggle-terms" role="tabpanel"> <div class="reading-toggle"> <div class="reading-toggle__switch"> <div class="form-entry__option__switch"> <label> <input type="checkbox" name="termsToggleSwitch" id="terms-toggle-switch" /> <span class="switch__slider"></span> <span class="option__label text-decoration-none font-size-md"> Highlight Glossary Terms </span> </label> </div> </div> <div class="reading-toggle__help"> <p> <em> Activate glossary term highlighting to easily identify key terms within the module. Once highlighted, you can click on these terms to view their definitions. </em> </p> </div> </div> </div> <div class="tabs__panel" id="tab-panel-toggle-ngss" aria-labelledby="tab-button-toggle-ngss" role="tabpanel"> <div class="reading-toggle"> <div class="reading-toggle__switch"> <div class="form-entry__option__switch"> <label> <input type="checkbox" name="ngssToggleSwitch" id="ngss-toggle-switch" /> <span class="switch__slider"></span> <span class="option__label text-decoration-none font-size-md"> Show NGSS Annotations </span> </label> </div> </div> <div class="reading-toggle__help"> <p> <em> Activate NGSS annotations to easily identify NGSS standards within the module. Once highlighted, you can click on them to view these standards. </em> </p> </div> </div> </div> <div class="reading-annotation-container"></div>  </div> </div> <div class="margin-3"> <script async src="https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js?client=ca-pub-9561344156007092" crossorigin="anonymous"></script>  <ins class="adsbygoogle" style="display:block" data-ad-client="ca-pub-9561344156007092" data-ad-slot="7634263342" data-ad-format="auto" data-full-width-responsive="true"></ins> <script> (adsbygoogle = window.adsbygoogle || []).push({}); </script> </div>   </article> </div> </main> <script id="ngssCommentdata" type="application/json"> [{"ngss_tag_id":null,"type":"cc","tag":null,"name":null,"description":null,"comment":"Similarities and differences in patterns can be used to sort, classify, communicate and analyze simple rates of change for natural phenomena and designed products.\r\n\r\nCC.1: Patterns","is_public":"1","mod_ngss_comment_id":"102","display_order":"1","dimension":"cc","dimension_full":"Crosscutting Concepts"},{"ngss_tag_id":null,"type":"p","tag":null,"name":null,"description":null,"comment":"Analyze data using tools, and\/or models (e.g., computational, mathematical) in order to make valid and reliable scientific claims.\r\n\r\nSEP.4: Analyze and Interpret Data","is_public":"1","mod_ngss_comment_id":"103","display_order":"2","dimension":"p","dimension_full":"Science and Engineering Practices"},{"ngss_tag_id":null,"type":"p","tag":null,"name":null,"description":null,"comment":"Plan and conduct an investigation to produce data to serve as the basis for evidence.\r\n\r\nSEP.2: Planning and Carrying Out Investigations","is_public":"1","mod_ngss_comment_id":"104","display_order":"3","dimension":"p","dimension_full":"Science and Engineering Practices"},{"ngss_tag_id":null,"type":"dci","tag":null,"name":null,"description":null,"comment":"Biodiversity describes the variety of species found in Earth\u2019s terrestrial and oceanic ecosystems. 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If a modest biological or physical disturbance to an ecosystem occurs, it may return to its more or less original status (i.e., the ecosystem is resilient), as opposed to becoming a very different ecosystem. Extreme fluctuations in conditions or the size of any population, however, can challenge the functioning of ecosystems in terms of resources and habitat availability. \r\n\r\nLS2.C: Ecosystem Dynamics, Functioning and Resilience","is_public":"1","mod_ngss_comment_id":"132","display_order":"31","dimension":"dci","dimension_full":"Disciplinary Core Ideas"},{"ngss_tag_id":null,"type":"dci","tag":null,"name":null,"description":null,"comment":"A complex set of interactions within an ecosystem can keep its numbers and types of organisms relatively constant over long periods of time under stable conditions. 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Extreme fluctuations in conditions or the size of any population, however, can challenge the functioning of ecosystems in terms of resources and habitat availability. \r\n\r\nLS2.C: Ecosystem Dynamics, Functioning, and Resilience","is_public":"1","mod_ngss_comment_id":"133","display_order":"32","dimension":"dci","dimension_full":"Disciplinary Core Ideas"},{"ngss_tag_id":null,"type":"dci","tag":null,"name":null,"description":null,"comment":"The sustainability of human societies and the biodiversity that supports them requires responsible management of natural resources. \r\n\r\nESS3.C: Human Impacts on Earth Systems","is_public":"1","mod_ngss_comment_id":"134","display_order":"33","dimension":"dci","dimension_full":"Disciplinary Core Ideas"}]</script>   <footer class="position-relative box-shadow-1 font-size-md" id="global-footer"> <h2 class="screen-reader-only">Page Footer</h2> <div class="back-to-top"> <div class="container wide"> <button class="button button--has-icon font-size-sm"> <span class="icon icon-arrow-up"></span> <span class="button__text">Back to top</span> </button> </div> </div> <div class="container wide padding-y-2"> <div class="grid grid--column-2--md grid--column-4--lg gap-4 grid--divider--fill-x"> <nav> <ul class="nav font-weight-bold"> <li> <a href="/en/library" title="Readings & quizzes"> Library </a> </li> <li> <a href="/en/glossary" title="Science terms"> Glossary </a> </li> <li> <a href="/en/classroom" title="Courses & bookmarks"> Classroom </a> </li> </ul> </nav> <nav> <ul class="nav"> <li><a href="/en/about">About</a></li> <li><a href="/en/help">Contact</a></li> <li><a href="/en/about/jobs">Jobs</a></li> <li><a href="/en/help/faq">FAQ</a></li> </ul> </nav> <div> <ul class="nav nav--horizontal margin-bottom-2"> <li> <a class="display-flex" href="https://www.nsf.gov" target="_blank" rel="noopener"> <img src="/images/sponsor-nsf.png" width="60" height="60" alt="US Education Department Logo" /> </a> </li> <li> <a class="display-flex" href="https://www.ed.gov/" target="_blank" rel="noopener"> <img src="/images/sponsor-doe.png" width="60" height="60" alt="US Education Department Logo" /> </a> </li> </ul> <p>Visionlearning is supported by the The National Science Foundation and the U.S. Department of Education. 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