Lab_13_Echinoderms

Lab_13_Echinoderms - Echinoderms Echinoderms Spiny Skin...

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Echinoderms Lab 13 Echinoderms are animals with spiny skin . Echinoderms are also Eukaryotic, Multicellular, Deuterostomes with a coelom . This phylum includes starfish, brittle stars, sea cucumbers, sea lilies, sea urchins, sand dollars, feather stars and sea daisies. All of these animals are bilaterally symmetrical with radial symmetry as a secondary adaptation . In the development of echinoderms the larva stage has bilateral symmetry. The bilateral larva develops into a radial adult. All echinoderms body structure includes a hard internal skeleton made of calcium and a water vascular system which includes their tube feet. Tube feet are involved in locomotion, feeding and gas exchange. Echinoderms are usually gonochoric with external fertilization. They inhabit marine environments. This phylum is divided into six classes, Asteroidea (Sea stars), Ophiuroidea (Brittlestars), Echinoidea (Sea urchins and Sand dollars), Crinoidea (Sea Lilies and Feather stars), Holothuroidea (Sea cucmbers) and Concentricycloidea (Sea Daisies). We will observe animals from Classes Asteroidea, Ophiuroidea, Crinoidea, Echinoidea and Holothuroidea. Class Asteroidea , are sea stars or starfish. Sea star external body structure usually consist of five arms, a central disc, hard skeleton, spiny skin, tube feet, a madreporite on the aboral surface and the mouth on the oral surface. The arms extend from the central disc and are composed of connected calcareous ossicles which are a part of the internal skeleton. Sea stars are carnivores or scavengers. They consume Bivalves, gastropods, crustaceans, polychaetas as well as echinoderms. These animals are able to regenerate damaged body parts. Class Ophiuridea
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Lab_13_Echinoderms - Echinoderms Echinoderms Spiny Skin...

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