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Worms

Worms. Flatworms. ectoderm. mesoderm. Bilateral symmetry Have organs & systems Primitive brain Pharynx: mouth tube 3 body layers Ectoderm Mesoderm Endoderm Gasses pass in/out by diffusion Reproduction: Asexual: stretch and break apart Sexual: “fencing”. Able to “regenerate”.

breanna-kramer
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Worms

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  1. Worms

  2. Flatworms ectoderm mesoderm • Bilateral symmetry • Have organs & systems • Primitive brain • Pharynx: mouth tube • 3 body layers • Ectoderm • Mesoderm • Endoderm • Gasses pass in/out by diffusion • Reproduction: • Asexual: stretch and break apart • Sexual: “fencing” Able to “regenerate” endoderm http://www.youtube.com/watch?v=0L_mJoG4nts

  3. Flatworms • Bilateral symmetry • Have organs & systems • Primitive brain • Pharynx: mouth tube • 3 body layers • Ectoderm • Mesoderm • Endoderm • Gasses pass in/out by diffusion • Reproduction: • Asexual: stretch and break apart • Sexual: “fencing”

  4. Flatworm Parasites • Tapeworms • Larvae enter through undercooked meat • Larvae grow • Scolex (head with hooks) attach to wall of intestines • Food absorbed through skin • Grow up to 12 meters • Eggs released in poop • Contaminated poop water consumed Larvae not killed in cooking process

  5. Roundworms (Nematodes) • Protostomes; Bilateral symmetry • Small in size (few mm) • Nerves control longitudinal muscles • What’s new? • Mouth and anus • Pseudocoelum: body cavity to aid with circulation & digestion • Separate male/female • Some free-living; Many parasites

  6. Roundworm Parasites • Hookworms • Larvae enter through bare feet walking in contaminated water • Migrate into lungs • Migrate into esophagus and swallowed into stomach • Larvae mature inside intestines • Mating occurs inside host • Eggs exit the host in poop https://www.youtube.com/watch?v=DxL2qHBetvI Egg

  7. Segmented Worms(Annelids) • What’s new? • Coelum: cavity to aid with circulation & digestions • Completely surrounded by muscle • Several organ systems • Complex digestive system • Circulatory sys: 2 blood vessels • Nervous sys: Primitive brain and nerve cord • Muscular sys: Circular & longitudinal muscles • Gas exchange through skin • Eat organic waste Longitudinal muscles Circular muscles

  8. Segmented Worm Reproduction M F . . . . . . • Hermaphroditic • Ventral surfaces press together • Mucus holds worms together • Sperm transferred to each • Sperm pouch forms • Sperm & eggs enter pouch as worm backs out • Baby worms develop inside pouch . F M

  9. Segmented Leeches • Live in calm, freshwater • Suckers attach to host • Release anaesthetic to hide presence • Can eat up to 10x own weight

  10. Segmented Leeches blood blood blood • Live in calm, freshwater • Suckers attach to host • Release anaesthetic to hide presence • Can eat up to 10x own weight • Medicinal use: • Help restore blood flow when body part is severed and reattached Ouch!

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