Bilateria-acoelomate, pseudocoelomate

Bilateria-acoelomate, pseudocoelomate - Bilateria-...

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Bilateria- Acoelomates, Pseudocoelomates Animalia (kingdom), Eumetazoa (sub-kingdom), Bilateria (Branch) A. Platyhelminthes (flat worms)- elongated, leg-less, dorso/ventrally flattened 1. Bilateria- bilateral symmetry, acoelomates (big advance) a. Most primitive group of Bilateria are flat worms because they’re acoelomates b. protostomate 2. Cephalization- distinct head area (concentration of sensory organs in anterior end) a. big advance because now there is a forward direction 3. Three definite germ layers- triploblastic (big advance) 4. Organs (big advance)- two or more tissues functioning together as units a. pharynx- muscular tube- epidermal and muscle tissue working together b. eyespots c. Brain- (Ganglia), group of nerve cells d. reproductive organs 5. Nervous “system”- brain and nerve cords a. not true brain- Ganglia, so not advanced enough for system b. two ventral nerve cords as apposed to one dorsal nerve cord- primitive 6. Excretory structure- protonephridia “first kidney”
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a. blind tube- one opening
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This note was uploaded on 04/07/2008 for the course BS 131 taught by Professor Smith during the Spring '08 term at University of the Sciences in Philadelphia.

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Bilateria-acoelomate, pseudocoelomate - Bilateria-...

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