Dr. Kathy S. Williams (email email@example.com)
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Contrast protostome & deuterostome characteristics.
(What’s a deuterostome?) *FIG. 32.5, 32.1, 32.6
u embryonic cleavageEchinoderms (Echinodermata) are the most basal of the deuterostomes.
u development of coelom
u formation of mouth
Adults are radially symmetrical, although larvae are bilaterally symmetrical.
u calcified internal skeleton (1012)
u water vascular system (624, * FIG. 33.37)
• Brittle stars (Ophiuroidea) - lost suckers on
tube feet; madreporite is oral.
• Sea cucumbers (Holothuroidea) have fleshy sausage-shaped bodies; endoskeleton reduced; madreporite reduced; tube feet near mouth modified to serve as tentacles.
You’re walking along a beach on a tropical island and come across a bunch of echinoderms in a tide pool … You find an unusual animal among them and want to determine what it is. You decide that is marine, has jointed appendages, and you see its bilaterally symmetrical larvae swimming around. You dissect one and find that it has a true coelom and complex excretory organs.
(2 pts) Is this an echinoderm? YES / NO (pick one)
(4 pts) Briefly explain your answer (give only one feature that is critical - or diagnostic).