30_Ward_Annelida+Outline

30_Ward_Annelida+Outline - mostly marine worms well...

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BIS2C W2011 Lecture 30 (2 March 2011) 1 Annelida Annelida – segmented worms (polychaetes, oligochaetes, leeches) Bilaterally symmetrical coelomate protostomes with following features… segmented (metameric) body each segment with paired bundles of chitinous setae (lost in leeches) each segment with parapodia (polychaetes only) body wall with inner longitudinal and outer circular muscles presegmental head and postsegmental terminus (pygidium ) closed circulatory system ; cutaneous respiration complete gut , with regional specialization well developed excretory system and central nervous system Annelid reproduction Polychaetes: usually dioecious, with external fertilization Clitellata: monoecious, with internal fertilization Asexual reproduction also common Annelid diversity ~16,500 species marine, freshwater and terrestrial Polychaeta (paraphyletic) and Clitellata Polychaeta (sand worms, tube worms, clam worms, etc.)
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Unformatted text preview: mostly marine worms well developed head with tentacles, etc. diverse feeding habits Clitellata – oligochaetes and leeches • freshwater and terrestrial • lack parapodia and tentacles • clitellum : thickened band, secretes cocoon for young BIS2C W2011 Lecture 30 (2 March 2011) 2 Oligochaetes – earthworms and related freshwater species • deposit feeders (recall Darwin’s observations) • cross-fertilizing hermaphrodites • eggs and sperm placed in protective cocoon Leeches • predators and blood-sucking ectoparasites • anterior and posterior suckers for attaching to prey • blood-feeders produce anesthetics (pain-killers), an anticoagulant , and a vasodilator Annelida Web sites: www.tolweb.org/Annelida http://en.wikipedia.org/wiki/Annelid http://www.ucmp.berkeley.edu/annelida/annelida.html http://www.annelida.net/ http://animaldiversity.ummz.umich.edu/site/accounts/information/Annelida.html...
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This note was uploaded on 03/09/2011 for the course BIS 2 taught by Professor Coolprof during the Spring '11 term at Bank Street College of Education.

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30_Ward_Annelida+Outline - mostly marine worms well...

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