ADW: Echinodermata: INFORMATION

<!DOCTYPE html> <html xmlns:og="http://ogp.me/ns#" lang="en" xml:lang="en"> <head> <title>ADW: Echinodermata: INFORMATION</title> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <link rel="canonical" href="https://animaldiversity.org/accounts/Echinodermata/" /> <script type="text/javascript" src="//code.jquery.com/jquery-3.6.0.min.js"></script> <script type="text/javascript" src="//code.jquery.com/jquery-migrate-3.3.2.min.js"></script> <script type="text/javascript" src="/static/js/compat.js"></script> <link rel="shortcut icon" href="https://animaldiversity.org/favicon.ico" /> <link href="//fonts.googleapis.com/css?family=Gentium+Book+Basic:400,400italic,700,700italic" rel="stylesheet" type="text/css" /> <link href="//fonts.googleapis.com/css?family=PT+Sans:400,700,400italic,700italic" rel="stylesheet" type="text/css" /> <link rel="stylesheet" type="text/css" href="/static/bootstrap/css/bootstrap.css" /> <link rel="stylesheet" href="/static/css/pica.styles.css" /> <link rel="stylesheet" href="/static/css/pica.print.css" media="print" />  <link rel="stylesheet" type="text/css" href="/static/colorbox/colorbox.css" /> <meta property="og:url" content="https://animaldiversity.org/accounts/Echinodermata/" /> <meta content="Echinodermata (sea stars, sea urchins, sea cucumbers, and relatives)" property="og:title" /> <meta content="website" property="og:type" /> <meta content="Animal Diversity Web" property="og:site_name" /> <meta content="https://animaldiversity.org/collections/contributors/Grzimek_inverts/Holothuroidea/Scotoplanes_globosa/medium.jpg" property="og:image" /> <meta name="twitter:card" content="summary" /> <meta name="twitter:site" content="@AnimalDiversity" /> <meta name="twitter:title" content="Echinodermata (sea stars, sea urchins, sea cucumbers, and relatives)" /> <meta name="twitter:description" content="Read about Echinodermata (sea stars, sea urchins, sea cucumbers, and relatives) on the Animal Diversity Web." /> <meta name="twitter:image:src" content="https://animaldiversity.org/collections/contributors/Grzimek_inverts/Holothuroidea/Scotoplanes_globosa/medium.jpg" /> <meta name="twitter:image:height" content="480" /> <meta name="twitter:image:width" content="537" /> <meta name="twitter:url" content="https://animaldiversity.org/accounts/Echinodermata/" /> <script type="text/javascript" src="/static/js/Hyphenator.js"></script> <link rel="stylesheet" href="/static/social-likes/social-likes_birman.css" /> <style> .social-likes { margin: 0; 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This phylum is the largest without any freshwater or terrestrial forms. <span class="citations"> (<a href="#3205f2da93a7337de42f4d9fc1c85891" class="citation">Brusca and Brusca, 2003</a>; <a href="#95a01fcfa2fe03161880240806bbe207" class="citation">Waggoner, 1999</a>)</span></p> </section> <section class="hyphenate"> <h3 id="geographic_range">Geographic Range</h3> <p audience="advanced intermediate">Mainly a marine group, echinoderms are found in all the oceans. <span class="citations"> (<a href="#3205f2da93a7337de42f4d9fc1c85891" class="citation">Brusca and Brusca, 2003</a>)</span></p> <ul class="keywords donthyphenate last"> <li class="keywords-header">Biogeographic Regions</li> <li> <a class="gloss" href="#20020917113601">arctic ocean</a> </li> <li> <span>indian ocean</span> </li> <li> <a class="gloss" href="#20020917114102">atlantic ocean</a> </li> <li> <a class="gloss" href="#20020917114731">pacific ocean</a> </li> <li> <span>mediterranean sea</span> </li> </ul> </section> <section class="hyphenate"> <h3 id="habitat">Habitat</h3> <p audience="advanced intermediate">Except for a few species which inhabit brackish waters, all echinoderms are benthic organisms found in marine environments. Echinoderms inhabit depths ranging from shallow waters at tide lines to the deep sea. <span class="citations"> (<a href="#7406ae3f29aca03fa41cbbe0724702ee" class="citation">Barnes, 1987</a>; <a href="#3205f2da93a7337de42f4d9fc1c85891" class="citation">Brusca and Brusca, 2003</a>; <a href="#9798f83a7ebf04eea9d067f28189be4e" class="citation">University of Alabama Center for Communication and Educational Technology, 2000</a>; <a href="#95a01fcfa2fe03161880240806bbe207" class="citation">Waggoner, 1999</a>)</span></p> <ul class="keywords donthyphenate "> <li class="keywords-header">Habitat Regions</li> <li> <a class="gloss" href="#20020904145595">temperate</a> </li> <li> <a class="gloss" href="#20020904145598">tropical</a> </li> <li> <a class="gloss" href="#20020904145371">polar</a> </li> <li> <a class="gloss" href="#20020904145582">saltwater or marine</a> </li> </ul> <ul class="keywords donthyphenate "> <li class="keywords-header">Aquatic Biomes</li> <li> <a class="gloss" href="#20020904145435">brackish water</a> </li> </ul> <ul class="keywords donthyphenate last"> <li class="keywords-header">Other Habitat Features</li> <li> <a class="gloss" href="#20020904145633">intertidal or littoral</a> </li> </ul> </section> <section class="hyphenate"> <h3 id="physical_description">Physical Description</h3> <p audience="advanced intermediate">Larvae range from a few millimeters to a few decimeters, while adults can range from less than 1 cm to 2 m. While adult forms are radially symmetrical, larval forms are always bilateral. The radial symmetry is secondarily derived. The pentaradial form, whether it has arms or not, has a central disc.</p> <p audience="advanced intermediate">An internal skeleton is present throughout members of the phylum. Ossicles, which make up the skeleton, are below an outer dermal layer. The skeletal and muscular arrangement varies among groups.</p> <p audience="advanced intermediate">Pedicellariae produced by the skeleton, are pincer-like structures. Found mainly in echinoids and asteroids, their function is debatable. They may be used to capture prey, clean, or hold items to disguise from predators.</p> <p audience="advanced intermediate">Echinoderms have a <a class="rewrite" href="/resources/biodidac/basicechino.jpg/medium.jpg">water vascular system</a> consisting of a network of radial canals, which extend through each of the five extensions (arms or rays) of the animal. Each canal has a lateral connection which leads to a tube foot, which may be composed of three parts. Internally is the ampulla and externally is the podia. At the end of the podia is usually a sucker.</p> <p audience="advanced intermediate">Grooves with rows of podia extending from the mouth are called the <a class="rewrite" href="/resources/biodidac/oralaster.jpg/medium.jpg">ambiculacra</a> . Between each ambiculacra is the interambulacrum. For groups of animals with "arms" (sea stars, for example), the interambulacrum is just the space between the ambiculacra. For other animals without furrows (sea cucumbers, for example), the areas are like the ambiculacra, but usually lack holes for the tube feet.</p> <p audience="advanced intermediate">The water vasuclar system opening, called a madreporite, lies on a particular interambulacrum. <a class="rewrite" href="/resources/biodidac/echinoletters.jpg/medium.jpg">Letters are used</a> to describe parts of echinoderms. The ambulacrum opposite the madreporite is section A. Moving clockwise, other parts are coded B through E. Sections C and D are termed the bivium while all the others are collectively termed the trivium. Interambulacrum sections are named using the letters of the ambulacra sections they are between (e. g. AB). <span class="citations"> (<a href="#7406ae3f29aca03fa41cbbe0724702ee" class="citation">Barnes, 1987</a>; <a href="#3205f2da93a7337de42f4d9fc1c85891" class="citation">Brusca and Brusca, 2003</a>; <a href="#95a01fcfa2fe03161880240806bbe207" class="citation">Waggoner, 1999</a>)</span></p> <ul class="keywords donthyphenate last"> <li class="keywords-header">Other Physical Features</li> <li> <a class="gloss" href="#20020916131519">ectothermic</a> </li> <li> <a class="gloss" href="#20020916125902">heterothermic</a> </li> <li> <a class="gloss" href="#20020904145642">bilateral symmetry</a> </li> <li> <a class="gloss" href="#20020904145808">radial symmetry</a> </li> </ul> </section> <section class="hyphenate"> <h3 id="development">Development</h3> <p audience="advanced intermediate">Echinoderms are deuterostomes. The larvae, which are planktotrophic or lecithotrophic, have 3-part paired coeloms. Embryonic coelomic structures have specific fates as the bilaterally symmetrical larvae metamorphose into radially symmetric adults. Adult pheromones may attract larvae, which tend to settle near conspecific adults. Metamorphosis in some species is triggered by adult pheromones. <span class="citations"> (<a href="#7406ae3f29aca03fa41cbbe0724702ee" class="citation">Barnes, 1987</a>; <a href="#3205f2da93a7337de42f4d9fc1c85891" class="citation">Brusca and Brusca, 2003</a>)</span></p> <ul class="keywords donthyphenate last"> <li class="keywords-header">Development - Life Cycle</li> <li> <a class="gloss" href="#20020904145364">metamorphosis</a> </li> </ul> </section> <section class="hyphenate"> <h3 id="reproduction">Reproduction</h3> <ul class="keywords donthyphenate last"> <li class="keywords-header">Mating System</li> <li> <a class="gloss" href="#20020904145483">polygynandrous (promiscuous)</a> </li> </ul> <p audience="advanced intermediate">Echinoderms are mainly gonochoristic (having separate sexes), with exceptions among the <a class="taxon-link" href="/accounts/Asteroidea/">asteroids</a>, <a class="taxon-link" href="/accounts/Holothuroidea/">holothurians</a> and <a class="taxon-link" href="/accounts/Ophiuroidea/">ophuroids</a>. Holothurians possess a single gonad, <a class="taxon-link" href="/accounts/Crinoidea/">crinoids</a> lack distinct gonads, while asteroids and <span class="taxon-name">echinoids</span> have multiple gonads. Echinoderm reproductive strategies vary from free spawning and indirect development to brooding and direct development. Spawning is probably a noctural event. <span class="citations"> (<a href="#7406ae3f29aca03fa41cbbe0724702ee" class="citation">Barnes, 1987</a>; <a href="#3205f2da93a7337de42f4d9fc1c85891" class="citation">Brusca and Brusca, 2003</a>)</span></p> <ul class="keywords donthyphenate last"> <li class="keywords-header">Key Reproductive Features</li> <li> <a class="gloss" href="#20020904145584">seasonal breeding</a> </li> <li> <span>gonochoric/gonochoristic/dioecious (sexes separate)</span> </li> <li> <span>simultaneous hermaphrodite</span> </li> <li> <span>sequential hermaphrodite</span> </li> <li> <a class="gloss" href="#20020904145786">sexual</a> </li> <li> <a class="gloss" href="#20020904145546">fertilization</a> <ul> <li> <a class="gloss" href="#20020904145726">external</a> </li> </ul> </li> <li> <a class="gloss" href="#20020904145572">oviparous</a> </li> </ul> <p audience="advanced intermediate">Parental investment ranges from no care after the release of eggs for free spawning to brooding the young. Brooding is found in polar and boreal echinoderms and some deep sea echinoderms, where environments are more difficult for the larvae. <span class="citations"> (<a href="#7406ae3f29aca03fa41cbbe0724702ee" class="citation">Barnes, 1987</a>; <a href="#3205f2da93a7337de42f4d9fc1c85891" class="citation">Brusca and Brusca, 2003</a>)</span></p> <ul class="keywords donthyphenate last"> <li class="keywords-header">Parental Investment</li> <li> <span>pre-fertilization</span> <ul> <li> <span>provisioning</span> </li> </ul> </li> <li> <span>pre-hatching/birth</span> <ul> <li> <span>provisioning</span> <ul> <li> <span>female</span> </li> </ul> </li> <li> <span>protecting</span> <ul> <li> <span>female</span> </li> </ul> </li> </ul> </li> </ul> </section> <section class="hyphenate"> <h3 id="behavior">Behavior</h3> <p audience="advanced intermediate">Most radially symmetric animals are sessile, however, echinoderms are able to move. The water vascular system originally functioned for collection and transport of food, but evolved to function for locomotion as well. <span class="citations"> (<a href="#7406ae3f29aca03fa41cbbe0724702ee" class="citation">Barnes, 1987</a>; <a href="#3205f2da93a7337de42f4d9fc1c85891" class="citation">Brusca and Brusca, 2003</a>)</span></p> <ul class="keywords donthyphenate last"> <li class="keywords-header">Key Behaviors</li> <li> <a class="gloss" href="#20020904145414">diurnal</a> </li> <li> <a class="gloss" href="#20020904145503">nocturnal</a> </li> <li> <a class="gloss" href="#20020904145472">motile</a> </li> <li> <a class="gloss" href="#20020904145585">sedentary</a> </li> </ul> </section> <section class="hyphenate"> <h3 id="communication">Communication and Perception</h3> <p audience="advanced intermediate">The non-centralized nervous system allows echinoderms to sense their environment from all sides. Adult pheromones may attract larvae, which tend to settle near conspecific adults. Metamorphosis in some species is triggered by adult pheromones. <span class="citations"> (<a href="#3205f2da93a7337de42f4d9fc1c85891" class="citation">Brusca and Brusca, 2003</a>)</span></p> <ul class="keywords donthyphenate "> <li class="keywords-header">Communication Channels</li> <li> <a class="gloss" href="#20020904145606">chemical</a> </li> </ul> <ul class="keywords donthyphenate "> <li class="keywords-header">Other Communication Modes</li> <li> <a class="gloss" href="#20020904145769">pheromones</a> </li> </ul> <ul class="keywords donthyphenate last"> <li class="keywords-header">Perception Channels</li> <li> <a class="gloss" href="#20020904145500">tactile</a> </li> <li> <a class="gloss" href="#20020904145606">chemical</a> </li> </ul> </section> <section class="hyphenate"> <h3 id="food_habits">Food Habits</h3> <p audience="advanced intermediate">Different groups have different feeding habits. Members of the <a class="taxon-link rank-class" href="/accounts/Crinoidea/">Crinoidea</a> sit with arms outstretched parallel to the currents and filter feed on passing particles. Most <a class="taxon-link rank-class" href="/accounts/Asteroidea/">Asteroidea</a> are predators or scavengers, everting their stomach (called a cardiac stomach), which secretes digestive enzymes on their prey. Some asteroids are also suspension feeders. Brittle stars of the <a class="taxon-link rank-class" href="/accounts/Ophiuroidea/">Ophiuroidea</a> are predators, deposit feeders, scavengers, and suspension feeders, which feed by outstretching their arms to capture prey. Ophiuroids lack an intestine and anus, and therefore have an incomplete digestive system. The members of <a class="taxon-link rank-class" href="/accounts/Echinoidea/">Echinoidea</a> are suspension feeders, herbivores, detritivores, and predators. Many have a group of hard plates which retract and grasp like teeth, commonly called Aristotle's lantern. This allows most sea urchins to graze on algae. Most <a class="taxon-link rank-class" href="/accounts/Holothuroidea/">Holothuroidea</a> are suspension or deposit feeders. Holothurians may also eviserate their digestive and other organs in response to predation or seasonal events. <span class="citations"> (<a href="#3205f2da93a7337de42f4d9fc1c85891" class="citation">Brusca and Brusca, 2003</a>; <a href="#95a01fcfa2fe03161880240806bbe207" class="citation">Waggoner, 1999</a>)</span></p> <ul class="keywords donthyphenate "> <li class="keywords-header">Primary Diet</li> <li> <a class="gloss" href="#20020904145419">carnivore</a> <ul> <li> <span>eats non-insect arthropods</span> </li> <li> <a class="gloss" href="#20020914202902">molluscivore</a> </li> <li> <a class="gloss" href="#20020904145488">scavenger</a> </li> </ul> </li> <li> <a class="gloss" href="#20020904145763">omnivore</a> </li> <li> <a class="gloss" href="#20020904145368">planktivore</a> </li> <li> <a class="gloss" href="#20020904145349">detritivore</a> </li> </ul> <ul class="keywords donthyphenate last"> <li class="keywords-header">Foraging Behavior</li> <li> <a class="gloss" href="#20020904145660">filter-feeding</a> </li> </ul> </section> <section class="hyphenate"> <h3 id="predation">Predation</h3> <p audience="advanced intermediate">Echinoderms in general are most vulnerable in their larval stage. As adults, <a class="taxon-link" href="/accounts/Asteroidea/">asteroids</a> have an anti-predator adaptation where they can lose an arm to a predator and the arm is later regenerated. <a class="taxon-link" href="/accounts/Holothuroidea/">Holothurians</a> discharge sticky tubules, known as <a class="rewrite" href="/resources/biodidac/holobody4.jpg/medium.jpg">Cuvierian tubules</a> , at a potential predator. <a class="taxon-link" href="/accounts/Lutrinae/">Otters</a> prey mainly on <a class="taxon-link" href="/accounts/Echinoidea/">sea urchins</a>. <span class="citations"> (<a href="#3205f2da93a7337de42f4d9fc1c85891" class="citation">Brusca and Brusca, 2003</a>)</span></p> <ul class="aside block-grid donthyphenate one-up"> <li> <dl> <dt>Known Predators</dt> <dd> <ul> <li>otters (<a class="taxon-link rank-subfamily" href="/accounts/Lutrinae/">Lutrinae</a>)</li> <li>flounders (<a class="taxon-link rank-family" href="/accounts/Pleuronectidae/">Pleuronectidae</a>)</li> <li>haddock (<a class="taxon-link rank-genus" href="/accounts/Melanogrammus/">Melanogrammus</a>)</li> </ul> </dd> </dl> </li> </ul> </section> <section class="hyphenate"> <h3 id="ecosystem_roles">Ecosystem Roles</h3> <p audience="advanced intermediate">Echinoderms are usually intricate parts of their ecosystems. Many <a class="taxon-link" href="/accounts/Asteroidea/">asteroids</a> are keystone species. <a class="taxon-link" href="/accounts/Echinoidea/">Sea urchins</a>, if not controlled by predators, may overgraze their habitat. Asteroids have several commensals, including <a class="taxon-link" href="/accounts/Polychaeta/">polychaetes</a> that feed on leftovers from the sea star's prey items. <span class="citations"> (<a href="#7406ae3f29aca03fa41cbbe0724702ee" class="citation">Barnes, 1987</a>; <a href="#3205f2da93a7337de42f4d9fc1c85891" class="citation">Brusca and Brusca, 2003</a>)</span></p> <ul class="keywords donthyphenate last"> <li class="keywords-header">Ecosystem Impact</li> <li> <a class="gloss" href="#20020904145561">keystone species</a> </li> </ul> </section> <section class="hyphenate"> <h3 id="economic_importance_positive">Economic Importance for Humans: Positive</h3> <p audience="advanced intermediate">Research on echinoderms has contributed to the overall knowledge of animal fertilization and development. Many echinoderms are easy to culture and maintain in a lab setting, and produce a large amount of eggs. Sea urchin eggs are also edible and often served in sushi bars. <span class="citations"> (<a href="#3205f2da93a7337de42f4d9fc1c85891" class="citation">Brusca and Brusca, 2003</a>; <a href="#9798f83a7ebf04eea9d067f28189be4e" class="citation">University of Alabama Center for Communication and Educational Technology, 2000</a>)</span></p> <ul class="keywords donthyphenate last"> <li class="keywords-header">Positive Impacts</li> <li> <a class="gloss" href="#20020904145418">food</a> </li> <li> <span>research and education</span> </li> </ul> </section> <section class="hyphenate"> <h3 id="conservation_status">Conservation Status</h3> <p audience="advanced intermediate">The European edible sea urchin, <a class="taxon-link rank-species" href="/accounts/Echinus_esculentus/">Echinus esculentus</a>, is listed as endangered by the IUCN. <span rank="Species" class="taxon-name rank-species">Isostichopus fuscus</span>, a holothurian, is listed by CITES. It occurs on the coasts of Ecuador, Galapagos, Mexico and Peru. <span class="citations"> (<a href="#923448e366fd8c948653f0d11a0738c2" class="citation">UNEP-WCMC, 2005</a>; <a href="#bcee7d8680eb3c34067fcbc66dec95a3" class="citation">World Conservation Monitoring Centre, 2004</a>)</span></p> <ul class="aside block-grid donthyphenate one-up"> <li> <dl> <dt>IUCN Red List <a href="http://www.iucnredlist.org/">[Link]</a></dt> <dd>Not Evaluated</dd> </dl> </li> </ul> </section> <section class="hyphenate"> <h3 id="comments">Other Comments</h3> <p audience="advanced intermediate">Since they are almost exclusively marine species, echinoderms are probably osmoconformers, with little ionic regulation. <span class="citations"> (<a href="#3205f2da93a7337de42f4d9fc1c85891" class="citation">Brusca and Brusca, 2003</a>)</span></p> </section> <section class="hyphenate"> <h3 id="contributors">Contributors</h3> <p>Renee Sherman Mulcrone (author). </p> </section> <section class="offscreen"> <h3 id="glossary">Glossary</h3> <div id="20020917113601"> <dl> <dt>Arctic Ocean</dt> <dd> <p>the body of water between Europe, Asia, and North America which occurs mostly north of the Arctic circle.</p> </dd> </dl> </div> <div id="20020917114102"> <dl> <dt>Atlantic Ocean</dt> <dd> <p>the body of water between Africa, Europe, the southern ocean (above 60 degrees south latitude), and the western hemisphere. It is the second largest ocean in the world after the Pacific Ocean.</p> <p align="center"> <img alt="World Map" src="/images/worldmap.2001.jpg" /> </p> </dd> </dl> </div> <div id="20020917114731"> <dl> <dt>Pacific Ocean</dt> <dd> <p>body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.</p> <p align="center"> <img alt="World Map" src="/images/worldmap.2001.jpg" /> </p> </dd> </dl> </div> <div id="20020904145642"> <dl> <dt>bilateral symmetry</dt> <dd> <p>having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.</p> </dd> </dl> </div> <div id="20020904145435"> <dl> <dt>brackish water</dt> <dd> <p>areas with salty water, usually in coastal marshes and estuaries.</p> </dd> </dl> </div> <div id="20020904145419"> <dl> <dt>carnivore</dt> <dd> <p>an animal that mainly eats meat</p> </dd> </dl> </div> <div id="20020904145606"> <dl> <dt>chemical</dt> <dd> <p>uses smells or other chemicals to communicate</p> </dd> </dl> </div> <div id="20020904145349"> <dl> <dt>detritivore</dt> <dd> <p>an animal that mainly eats decomposed plants and/or animals</p> </dd> </dl> </div> <div id="20020904145414"> <dl> <dt>diurnal</dt> <dd> <ol class="arabic simple"> <li>active during the day, 2. lasting for one day.</li> </ol> </dd> </dl> </div> <div id="20020916131519"> <dl> <dt>ectothermic</dt> <dd> <p>animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature</p> </dd> </dl> </div> <div id="20020904145726"> <dl> <dt>external fertilization</dt> <dd> <p>fertilization takes place outside the female's body</p> </dd> </dl> </div> <div id="20020904145546"> <dl> <dt>fertilization</dt> <dd> <p>union of egg and spermatozoan</p> </dd> </dl> </div> <div id="20020904145660"> <dl> <dt>filter-feeding</dt> <dd> <p>a method of feeding where small food particles are filtered from the surrounding water by various mechanisms. Used mainly by aquatic invertebrates, especially plankton, but also by baleen whales.</p> </dd> </dl> </div> <div id="20020904145418"> <dl> <dt>food</dt> <dd> <p>A substance that provides both nutrients and energy to a living thing.</p> </dd> </dl> </div> <div id="20020916125902"> <dl> <dt>heterothermic</dt> <dd> <p>having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.</p> </dd> </dl> </div> <div id="20020904145633"> <dl> <dt>intertidal or littoral</dt> <dd> <p>the area of shoreline influenced mainly by the tides, between the highest and lowest reaches of the tide. An aquatic habitat.</p> </dd> </dl> </div> <div id="20020904145561"> <dl> <dt>keystone species</dt> <dd> <p>a species whose presence or absence strongly affects populations of other species in that area such that the extirpation of the keystone species in an area will result in the ultimate extirpation of many more species in that area (Example: sea otter).</p> </dd> </dl> </div> <div id="20020904145364"> <dl> <dt>metamorphosis</dt> <dd> <p>A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.</p> </dd> </dl> </div> <div id="20020914202902"> <dl> <dt>molluscivore</dt> <dd> <p>eats mollusks, members of Phylum Mollusca</p> </dd> </dl> </div> <div id="20020904145472"> <dl> <dt>motile</dt> <dd> <p>having the capacity to move from one place to another.</p> </dd> </dl> </div> <div id="20020904145503"> <dl> <dt>nocturnal</dt> <dd> <p>active during the night</p> </dd> </dl> </div> <div id="20020904145763"> <dl> <dt>omnivore</dt> <dd> <p>an animal that mainly eats all kinds of things, including plants and animals</p> </dd> </dl> </div> <div id="20020904145572"> <dl> <dt>oviparous</dt> <dd> <p>reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.</p> </dd> </dl> </div> <div id="20020904145769"> <dl> <dt>pheromones</dt> <dd> <p>chemicals released into air or water that are detected by and responded to by other animals of the same species</p> </dd> </dl> </div> <div id="20020904145368"> <dl> <dt>planktivore</dt> <dd> <p>an animal that mainly eats plankton</p> </dd> </dl> </div> <div id="20020904145371"> <dl> <dt>polar</dt> <dd> <p>the regions of the earth that surround the north and south poles, from the north pole to 60 degrees north and from the south pole to 60 degrees south.</p> </dd> </dl> </div> <div id="20020904145483"> <dl> <dt>polygynandrous</dt> <dd> <p>the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.</p> </dd> </dl> </div> <div id="20020904145808"> <dl> <dt>radial symmetry</dt> <dd> <p>a form of body symmetry in which the parts of an animal are arranged concentrically around a central oral/aboral axis and more than one imaginary plane through this axis results in halves that are mirror-images of each other. Examples are cnidarians (Phylum Cnidaria, jellyfish, anemones, and corals).</p> </dd> </dl> </div> <div id="20020904145582"> <dl> <dt>saltwater or marine</dt> <dd> <p>mainly lives in oceans, seas, or other bodies of salt water.</p> </dd> </dl> </div> <div id="20020904145488"> <dl> <dt>scavenger</dt> <dd> <p>an animal that mainly eats dead animals</p> </dd> </dl> </div> <div id="20020904145584"> <dl> <dt>seasonal breeding</dt> <dd> <p>breeding is confined to a particular season</p> </dd> </dl> </div> <div id="20020904145585"> <dl> <dt>sedentary</dt> <dd> <p>remains in the same area</p> </dd> </dl> </div> <div id="20020904145786"> <dl> <dt>sexual</dt> <dd> <p>reproduction that includes combining the genetic contribution of two individuals, a male and a female</p> </dd> </dl> </div> <div id="20020904145500"> <dl> <dt>tactile</dt> <dd> <p>uses touch to communicate</p> </dd> </dl> </div> <div id="20020904145595"> <dl> <dt>temperate</dt> <dd> <p>that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).</p> </dd> </dl> </div> <div id="20020904145598"> <dl> <dt>tropical</dt> <dd> <p>the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.</p> </dd> </dl> </div> </section> <section class="hyphenate"> <h3 id="references">References</h3> <p id="7406ae3f29aca03fa41cbbe0724702ee">Barnes, R. 1987. <span style="font-style: italic">Invertebrate Zoology</span>. Orlando, Florida: Dryden Press. </p> <p id="3205f2da93a7337de42f4d9fc1c85891">Brusca, R., G. Brusca. 2003. <span style="font-style: italic">Invertebrates</span>. Sunderland, Massachusetts: Sinauer Associates, Inc.. </p> <p id="923448e366fd8c948653f0d11a0738c2">UNEP-WCMC, 2005. "Isostichopus fuscus" (On-line). UNEP-WCMC Species Database: CITES-Listed Species. Accessed January 21, 2005 at <tt><a href="http://www.cites.org/eng/resources/species.html">http://www.cites.org/eng/resources/species.html</a></tt>. </p> <p id="9798f83a7ebf04eea9d067f28189be4e">University of Alabama Center for Communication and Educational Technology, 2000. "Phylum Echinodermata – echinoderms" (On-line). Accessed January 16, 2005 at <tt><a href="http://www.ccet.ua.edu/expedition/scsstarsurcbrit.htm">http://www.ccet.ua.edu/expedition/scsstarsurcbrit.htm</a></tt>. </p> <p id="4877f14dbe26da78572a24bf0117eccc">University of Paisley, 1998. "Echinodermata" (On-line). Accessed January 16, 2005 at <tt><a href="http://www-biol.paisley.ac.uk/courses/Tatner/biomedia/units/echi1.htm">http://www-biol.paisley.ac.uk/courses/Tatner/biomedia/units/echi1.htm</a></tt>. </p> <p id="95a01fcfa2fe03161880240806bbe207">Waggoner, B. 1999. "Introduction to the Echinodermata" (On-line). Accessed January 16, 2005 at <tt><a href="http://www.ucmp.berkeley.edu/echinodermata/echinodermata.html">http://www.ucmp.berkeley.edu/echinodermata/echinodermata.html</a></tt>. </p> <p id="bcee7d8680eb3c34067fcbc66dec95a3">World Conservation Monitoring Centre, 2004. "Echinus esculentus" (On-line). 2004 IUCN Red List of Threatened Species. Accessed January 21, 2005 at <tt><a href="http://www.iucnredlist.org/search/details.php?species=7011">http://www.iucnredlist.org/search/details.php?species=7011</a></tt>. </p> </section> </div> </div> <div class="span2_5 right sidebar"> <div class="well" id="pocket-guide-link"> <a href="https://itunes.apple.com/us/app/adw-pocket-guide/id916179421?mt=8" target="_blank"><i class="icon-download icon-white" style="vertical-align: bottom"></i> ADW Pocket Guides on the iOS App Store! </a> <p>The Animal Diversity Web team is excited to announce ADW Pocket Guides!</p> <p> <a href="/news/5009059054038197651/">Read more...</a> </p> </div> <h2 class="offscreen">Search</h2> <div id="site-search"> <form action="/search" method="GET"> <label for="q" class="offscreen">Enter search text</label> <input value="" id="q" name="q" class="span12" size="15" type="text" placeholder="Search ADW" /> <button class="btn"> <i class="icon-zoom-in"></i> <span class="offscreen">Search</span> </button> <p 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ADW: Echinodermata: INFORMATION