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Echinodermata notes

Echinodermata notes - tube • Circulatory system = central...

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Echinodermata! the first definitive members of the phylum = Cambrian period. second-largest grouping of deuterostomes, after the chordates; largest phylum that has no freshwater or terrestrial representatives. main subdivisions of Echinoderms : motile Eleutherozoa ,(starfish), Ophiuroidea (brittle stars), Echinoidea (sea urchins and sand dollars) and Holothuroidea (sea cucumbers) Echinoderms possess a water vascular system, a network of fluid-filled canals that function in gas exchange = no gill slits very simple, often simply leading directly from mouth to anus (but has a digestive
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Unformatted text preview: tube) • Circulatory system = central ring and five radial vessels, but no heart • sexually mature after approximately two to three years, eggs and sperm cells are released into open water, where fertilization takes place (except for some species of starfish) • Some echinoderms (starfish) can regenerate. From one missing arm, it can generate a completely new starfish. • Feeding - filter-feeders, STARFISH – invert stomach…engulf food, digest it once, then send it to the second stomach to digest it again…ok...
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