18%20Misc09[1]

18%20Misc09[1] - XVIII Miscellaneous Phyla 2009 Word Slide...

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63 XVIII. Miscellaneous Phyla 2009 Word Slide: Cheap Thoughts by Jack O’Brien A. Phylum Mollusca, Class Bivalvia, Family Unionidae 1. Larvae of freshwater mussels parasitize freshwater fish 2. GLOCHIDIA larvae a. Burrow into fish gills b. Acquire nutrients from fish c. Fish swim upstream d. Larvae drop off fish when they become juvenile mussels Picture Slide: Glochidia Larvae of Freshwater Mussels; Glochidium (Barnes, R. 1968, InvertebrateZoology , p. 345) & Life-cycle of Unionid mussels (Pearse & Buchsbaum, 1987, Living Invertebrates p. 356) Picture Slide: Glochidia Larvae of Freshwater Mussels; Some unionid mussels extrude fish-like “lures” containing infective glocidia larvae that parasitize the gills of predatory fish that strike the egg-sacs; Neves, R. et al., 1997, in Aquatic Fauna in Peril , p.43 & Chaplin, S. et al., 2000, in Precious Heritage , p. 179. Picture Slide: “Losing More Species”, Mobile Press Register August 10, 2008 3. Many unionid species threatened a. Dam construction (1) Tennessee Valley Association (TVA) generates hydroelectric power (2) Tennessee-Tombigee Waterway enables barges to move from Mobile to Knoxville b. Man-made changes in Appalachian rivers have altered abundance of potential fish hosts and interfered with life-cycles of unionids Picture Slides Tennessee-Tombigee Waterway maps, http://www.tenntom.org/images/maps/TTWcompmap.jpg & http://www.tenntom.org/images/maps/TTWtransarterymap.jpg Picture Slide: Regional Concentrations of Aquatic Diversity; Based on the number of at- risk fish and mussel species, the Tennessee-Cumberland and Mobile River basins have extraordinarily diverse assemblages of freshwater animal species. Chaplin, S. et al., 2000, in Precious Heritage , p. 181 B. Phylum Nematomorpha = Horsehair or Gordian Worms (Chapter 31) 1. Characteristics a. Superficially resemble nematodes (1) No segmentation (2) Grow by molting (3) Pseudocoelomate b. Differences (1) Ends are rounded rather than tapered (2) Non-functional rudimentary gut; they absorb nutrients across their cuticle Picture Slide: Characteristic blunt anterior & branched posterior of a nematomorph worm; Pearse J. et al ., 1987 Living Invertebrates , p. 294 2. Life cycle of one species that infects crickets Picture Slide: Generalized life-cycle of a nematomorph (Fig 31.8, p. 492)
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18%20Misc09[1] - XVIII Miscellaneous Phyla 2009 Word Slide...

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