Phylum Echinodermata

Phylum Echinodermata - animals a flowerlike or plantlike...

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Phylum Echinodermata There are 6000 species of echinoderms; all extant species are marine. The phylum Echinodermata includes the sea urchins, sea stars, sea cucumbers, and starfish. Most adults have radial symmetry , while their larvae are bilaterally symmetrical . Echinoderms have an endoskeleton consisting of calcareous plates bearing spines. Radial symmetry appears to be an advantage to the mostly bottom- dwelling echinoderms, who can thus feed in every direction. Adult echinoderms have no brain. Members of the phylum have a water vascular system that powers their multitude of tube feet. Classification of Echinodermata
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There are several taxonomic classes of echinoderms of varying familarity to the general public. The Class Crinoidea The class Crinoidea includes about 600 species of crinoids, the stalked sea "lilies" and the motile feather stars. Their branched arms are used for filter-feeding and give the
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Unformatted text preview: animals a flowerlike or plantlike appearance (hence the term sea lily). Crinoid stalks and blastoid heads are common fossils in certain parts of North America. The Class Holothuroidea The class Holothuroidea has 1,500 species of sea cucumbers. Sorry, these are NOT good eating as a general rule! Holothuroideans have a long leathery body, and feed by tentacles located around their mouth. The Class Echinoidea Scientists generally place about 950 species of sea urchins and sand dollars are in the class Echinoidea. Both sea urchins and sand dollars have spines thar they use for locomotion, defense, and burrowing. Sea urchins have long, blunt spines. Sand dollars are flattened with a five-part flowerlike pattern of pores for skin projections....
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Phylum Echinodermata - animals a flowerlike or plantlike...

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