topic15[1]

topic15[1] - Topic 15: Deuterostomes: Echinodermata and...

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Topic 15: Deuterostomes: Echinodermata and Hemichordata (Ch. 33) I. Deuterostomia (clade) A. defined primary by molecular evidence B. some defining developmental traits (see previous notes), but those can get fuzzy C. clade includes the following phyla that we will cover: 1. Phylum Echinodermata (clade) 2. Phylum Hemichordata (clade) 3. Phylum Chordata (clade) 4. The Phylum Echinodermata and Hemichordata are grouped into Ambulacraria II. Phylum Echinodermata - urchins, sea stars, sea cucumbers A. marine; ~7000 living species; in fossil record back to over 650 MYA B. name means “spiny skin”, reference to their endoskeleton 1. calcium rich plates below skin 2. living tissue when formed; usually fused into hard shell in adults 3. pores in endoskeleton for water vascular system (madreporite, tube feet) C. water-vascular system - hydraulic system for moving, feeding 1. water enters though madreporite , opening typically opposite mouth 2. water from madreporite moves though stone canal 3. water then enters the
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topic15[1] - Topic 15: Deuterostomes: Echinodermata and...

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