9. Annelids II - 1 Phylum Phylum Annelida...

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Unformatted text preview: 1 Phylum Phylum Annelida Annelida "little rings" "little rings" Segmented worms Segmented worms Coelom Coelom- True True coelom coelom , lined by mesoderm , lined by mesoderm Triploblastic Triploblastic , Organ Grade , Organ Grade Segmentation Segmentation Metamerism Metamerism- serial repetition of parts serial repetition of parts Metamerism : serial repetition of parts Seen in 3 major groups Annelids : segmentation of coelom by transverse septae Arthropods : limb and musculature segmented Chordates : body wall musculature Chordate metamerism convergent with Ann. and Arth. Ann. and Arth. - may be convergent as well historically thought to be homologous, but new phylogenies more confusing. 4 Major Taxa you need to know: Class Polychaeta Class Clitellata Subclass Oligochaeta Sublcass Hirudinoidea Class Polychaeta: Many (poly) chaetae on parapodia, no clitellum, most separate sexes, often indirect development with trochophore larvae Marine – mainly Class Clitellata No parapodia, reduced or absent chaetae, hermaphroditic, complex reproductive system with clitellum, direct development Subclass Oligochaeta: No parapodia Few chaetae (oligo) Freshwater and marine, terrestrial Subclass Hirudinoidea: No parapodia No chaetae Lack internal segmentation walls Freshwater and marine, terrestrial General Body Plan Presegmental Prostomium - eyes, antennae, palps, ganglia Postsegmental tail - anus Trunk Segments - In Each Segment: body wall muscles gut (diverticula) circulatory system nervous system reproductive system Segments : similar, repeated = HOMONOMOUS Prostomium : presegmental, w/ ganglia, sensory structures Pygidium : postsegmental 2...
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This note was uploaded on 01/27/2010 for the course BIO 37282 taught by Professor Padilla during the Fall '10 term at SUNY Stony Brook.

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9. Annelids II - 1 Phylum Phylum Annelida...

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