Derived from mesoderm and covered in epidermis the

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Unformatted text preview: cles ! derived from mesoderm, and covered in epidermis. The skeletal plates (ossicles) are connected by a form of collagen which can be stiff or flexible ! neuronal control of body tone without muscle action. •, ! flatten urchin bilateral symmetry (secondarily derived) Sea lily mouth-> stomach 1-> stomach 2-> anus Mouth on oral (under) side regions with tube feet = ambulacra has 2 stomachs: fluffy stomach and cardiac stomach two stomachs in asteroids water vascular system some has calcium ring that attaches to ^synapomorphy the bottom. the middle part then pulled up and become a suckers Hard calcium ossicles in the skin in every arm: 2 line of tube feet, reproductive structure (gonads), and digestive gland over the whole thing. use the tube feet to eat Sea stars (Asteroidea) common, largely predatory (hold the bivalve close) Fight: combined tube foot forces versus bivalve adductor muscles and the role of the fluffy (cardiac) stomach catch collagen work like a ratchet water vascular system is used for: -locomotion -feeding -respiration as soon as the bivalve opens a bit the fluffy stomach comes out of the mouth and sticks itself out in the gap and begins secreting digestive fluid sea stars usually wins Class Echinoidea: sea ur...
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This document was uploaded on 04/13/2013.

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