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Platyhelminthes: flatworms

Platyhelminthes: flatworms. Cestoda: tapeworms Turbellaria: free living flatworms like Planaria Trematoda: flukes like Schistosoma. Platyhelminthes. Have bilateral symmetry Can be free living or parasitic Have 3 germ layers and are acoelmate (lacking a cavity between gut and outer wall)

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Platyhelminthes: flatworms

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  1. Platyhelminthes: flatworms • Cestoda: tapeworms • Turbellaria: free living flatworms like Planaria • Trematoda: flukes like Schistosoma

  2. Platyhelminthes • Have bilateral symmetry • Can be free living or parasitic • Have 3 germ layers and are acoelmate (lacking a cavity between gut and outer wall) • Move by using cilia or by contracting their muscles

  3. Platyhelminthes: fluke life cycle Sheep liver fluke • Schistosoma Life Cycle-

  4. Tapeworm: Cestoda • Tapeworm scolex tapeworm

  5. Turbellaria; planaria (free living)

  6. More turbellarians

  7. Flatworm videos • http://www.youtube.com/watch?v=voMKJea91gg free living flatworm • http://www.youtube.com/watch?v=Ich4Y_K6GuM&feature=PlayList&p=E9E1093124E2F9C9&playnext=1&index=11 planaria eating • http://www.youtube.com/watch?v=T6pAfQInf2c tapeworm in intestine

  8. Phylum Rotifera • Are tiny animals that mainly inhabit fresh water, although some live in the sea or in damp soil. • Have bilateral symmetry and are truly multicellular. • “Rotifer,” derived from Latin, means “wheel-bearer”—a reference to the crown cilia that draws a vortex of water into the mouth. • Pseudocoelomate http://www.youtube.com/watch?v=OSoFwCkTbj0&feature=related

  9. Phylum Rotifera • Have specialized organ systems—including a complete digestive tract: with a separate mouth and anus. • Perform a type of reproduction called parthenogenesis (virgin birth): females producing more females from unfertilized eggs.

  10. Nematoda: roundworms • Complete digestive tract • Pseudocoelomate • Hydrostatic skeleton under pressure which means only one shape is possible • Longitudinal muscles allow for wriggling, but no circular muscles

  11. Phylum Nematoda • Reproduction is usually sexual—females are generally larger than males. • Fertilization is internal, and a female can deposit 100,000 or more fertilized eggs per day. • The zygotes of most species are resistant cells capable of living in harsh conditions. Hookworm

  12. Roundworms Pinworm Ascaris: intestinal roundworm 1,000,000 cases in USA: 1.2 billion worldwide Heartworm

  13. Ascaris life cycle

  14. Removal of Guinea Worm http://www.youtube.com/watch?v=mUz9gqLmyQ0

  15. nematodes • http://www.youtube.com/watch?v=JBLemM3tzRM soil nematodes • http://www.youtube.com/watch?v=gmFHnQKbSM8 lymphatic filariasis (elephantiasis) 1 billion worldwide

  16. Annelida: segmented worms • Eucoelomate • Segmented body plan • Closed circulatory system • Protostome

  17. Annelida: key structures • Metanephridia:kidney like structures • Setae/ parapodia • Clitellum • Aortic arches

  18. leeches • Fused segments to allow for blood storage • Blood thinner released to help sucking

  19. http://www.youtube.com/watch?v=DZig6EL5B6A&feature=PlayList&p=F648EFCC1BE6AAA3&playnext=1&index=10http://www.youtube.com/watch?v=DZig6EL5B6A&feature=PlayList&p=F648EFCC1BE6AAA3&playnext=1&index=10 Earthworms in Australia Earthworms are hermaphroditic. They fertilize each other with the clitellum secreting a mucus sack to collect the eggs and sperm. This sack is then placed into the ground until babies are developed.

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