Phylum Phylum Mollusca

Phylum Phylum Mollusca - -torsion: mantle rotates 180...

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Phylum Mollusca -Synapomorphies: radula, mantle, muscular foot, calcareous spicules produced by females -not segmented -mantle purposes: jet propulsion in cephlapods, gills in bivalves pumping water, respiratory in gastropods (snails) -muscular foot purposes: locomotion for snails (gastropods), clam uses to dig, tentacles and funnel in cephlapods -calcareous spicules to form shell -muscle contraction in foot for locomotion -shell on top of mantle, mantle secretes shell -radula used for scraping (example: algae) , 250000 “teeth” on its surface, made of chitin -chitin makes of many structures, setae, shell, radula, -cone snails: radula modified into harpoon -mobile trochophore larvae – cilia -some adults become sessile -gastropods – snails – 40000 species – mobile -snails, slugs, and nudibranchs -freshwater, marine, and terrestrial
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Unformatted text preview: -torsion: mantle rotates 180 degrees bringing anus over the mouth -univalve -freshwater snails evolved from terrestrial snails, so they still have to come to the surface to breathe air-marine nudibranches: no shell, benthic, feed on cnidarians and sponges-terrestrial gastropod example: slug: shell less, taste buds and primitive eyes, mucus used for attachment -abalome: opening on sides, low on food chain-bivalves clams, etc. 20000 species sessile-lost radula, reduced head, mostly filter feeders, gills used for respiration and feeding, foot used to dig into sand/sediment, ability to filter the water of light pollution-tridacna giant clams (5 feet), cultured for food-polyplacophora chitons 1000 species -flattened, shell of 7-8 plates: hinged, attached to rocks, grazing on algae...
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This note was uploaded on 11/11/2009 for the course BIS 1b taught by Professor Kimsey during the Fall '08 term at UC Davis.

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