ZOO 2700 Study Guide - Midterm Guide: Bivalve Shell, Dicrocoelium Dendriticum, Xenoturbella

• School: University of Guelph
• Department: Zoology
• Course: ZOO 2700
• Professor: Alex Smith

Document Summary

Freeliving, monogenean ectoparasites, cestodes + trematodes endoparasites. Acoelomorph flatworms related to xenoturbella (new phyla w/in deutorostome and maybe even w/in xenoturbella. Nervous system: nerve cords, nerve nets, statocysts (gravity), ciliary (mechano)receptors, Chemoreceptors, pigmented eye spots, photoreceptor (strong, (-) phototactic) Digestive system: mouth, sucking pharynx, no anus, lateral branches, phagocytic/gland cells, gastro-vascular. Apomorphies: neodermis (tegument)[parasite adaptation], (s)-microvili surface, non-ciliated, syncytial (multi-nucleated mass of cytoplasm not separated into cells, more control of what leaves/enters w/ cytoplasmic bridges), (f)-protection form gut enzymes, absorptive surface. Larval epidermis is ciliated cell/syncytial neodermis combo, 2+hosts, molluscs are 1st host. Aspidogastrea: large, complex ventral sucker, mostly fish and turtles. Digenea: miracidium larva w/ transverse bands of ciliated cells, mollusc- >vert, 2 suckers (oral feeding, ventral attachment), bulbous pharynx, circular muscle (exterior and basal), longitudinal muscle (middle and external) Tricchobilharzia, swimmers itch, snail>duck (try to enter human skin but not a host) Schistosoma, schistosomiasis snail>human, 2nd most infectious next to malaria.