3454lablecture3 - Lecture 3 Acoelomate and Pseudocoelomate phyla Triploblastic acoelomate organ level of organization true muscles No respiratory

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Lecture 3 Acoelomate and Pseudocoelomate phyla Triploblastic, acoelomate, organ level of organization, true muscles No respiratory or circulatory system, have mouth opening only Hermaphroditic, most complex system is reproductive system Cephalization – trend toward specialized head region with sensory organs in head, also helps with better locomotion Bilateral symmetry, central nervous system with nerve cords and ganglia PHYLUM PLATYHELMINTHES CLASS TURBELLARIA (FLATWORMS OR PLANARIANS) Freshwater or marine, few are parasitic Have ventral cilia and glide on a mucus trail created by goblet cells Extendable pharynx – 3-branched intestine – intestines continue branching to feed the tissues of the body Eyespots (light sensitive, not image forming) CLASS TREMATODA (FLUKES) Mostly endoparasites, largest group of flatworms, non-extendable pharynx Esophagus, 2-branched intestine (diverticulum) Life cycle of liver fluke (book pictures not to scale) Several intermediate hosts:
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This note was uploaded on 11/29/2009 for the course BIOLOGY 3454 taught by Professor Nelson during the Spring '09 term at UT Arlington.

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3454lablecture3 - Lecture 3 Acoelomate and Pseudocoelomate phyla Triploblastic acoelomate organ level of organization true muscles No respiratory

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