ZOO 2700 Lecture Notes - Lecture 13: Escape Response, Scleroprotein, Oligochaeta
28 Mar 2018
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Document Summary
Pair of mesodermal somites with coelomic spaces (development of the mesoderm in an annelid. Pair of coelomoducts (ciliated excretory and reproductive channels. Pair of ganglia on a ventral nerve cord. Segmentation: derived from the ectoderm, con be confined to only ectoderm. Metamerism: derived from the mesoderm, confined to ectoderm and mesoderm. Build a large organism from a simple plan. Apomorphies: chaetae, cuticular structures produced by epidermal cells, 4 bundles of simple chaetae per segment, chaetae made of -chitin, traction, other tasks. - chitin: adjacent parallel molecules with same polarity. -chitin: adjacent parallel molecules with opposite polarity. Specialization of appendages and other structures for different functions. Refers to structures which though different have the same segmental, embryonic, and evolutionary origin. Tagmata: structurally differentiated groups of segments specialized to perform specific functions for the whole organism (head, thorax, abdomen) Diversity: 3 major lifestyles: burrowers, crawlers, swimmers. Large diameter, low resistance = rapid impulse conduction. Conduction velocity can be as fast as 20m/s.
