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Lecture 5 Animal Evolution – The Invertebrates. Echinoderms. Means spiny-skinned. Coelomate animals with spines, spicules/plates of calcium carbonate in the body wall-serve as defensive functions. E.g Star fishes, sea urchins, sea cucumbers Most have well-developed internal skeleton .
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Echinoderms • Means spiny-skinned. • Coelomate animals with spines, spicules/plates of calcium carbonate in the body wall-serve as defensive functions. • E.g Star fishes, sea urchins, sea cucumbers • Most have well-developed internal skeleton. • Adults are radial with some bilateral symmetry. • Active preadtors
Echinoderms • Adults are brainless but with decentralized nervous system which responds to food, predators and so forth coming in any directions. • Have tube-feet. • Tube-feet: • fluid-filled, muscular structures & sucker-like adhesive disks. • used for walking, burrowing, clinging to rocks, gripping clams/snails. • components of a water-vascular system unique to echinoderms.