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Invertebrates

Invertebrates. Asymmetrical (no symmetry at all) No true body cavities (coeloms), just cells and tissues surrounding a water-filled space. Debate on whether a sponge is multicellular or colonial. Sponges. http://www.youtube.com/watch?v=RmPTM965-1c (sponges)

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Invertebrates

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  1. Invertebrates

  2. Asymmetrical (no symmetry at all) • No true body cavities (coeloms), just cells and tissues surrounding a water-filled space. • Debate on whether a sponge is multicellular or colonial.

  3. Sponges • http://www.youtube.com/watch?v=RmPTM965-1c (sponges) • http://www.youtube.com/watch?v=KOFFzXNYJG0 (sponges) • http://www.youtube.com/watch?v=IyUFG_F3090 (choanocytes)

  4. Intracellular digestion • There is no digestion in the spongocoel.

  5. Amoebocyte: named because they move by pseudopods, - take food from the choanocyte, form the skeletal fibers (spicules) • Spongin: a network of flexible fiber proteins in body wall • Spicules: fibers made from the amoebocyte, they are sharp and made from calcium carbonate or silica. Function: provide structural support as well as defense against predators.

  6. Choanocyte: flagellated cells, also called collar cells, that line the spongocoel and trap food • Porocytes: donut shaped pores that open and close to control water flow • Ostia: small pores in the walls of sponges, water enters • Osculum: large opening that water flows out of, under certain conditions cells around the osculum contract (open and close) • Spongocoel: the central cavity of a sponge

  7. Cnidaria • Radial symmetry (infinite lines of symmetry) • Two germ layers (TRUE germ layers): Diploblastic • No coelom • Extracellular digestion in the gastrovascular cavity

  8. Cnidarin: general body plan

  9. Cnidocytes with nematocyst harpoons: namesake of the phylum • Before After Bumps are the cnidocytes

  10. Planula larvae • Ciliated larva stage of jellyfish and corals

  11. Cnidaria: Scyphozoa

  12. http://www.youtube.com/watch?v=v9j9iO6Zy4o&feature=PlayList&p=E9E1093124E2F9C9&playnext=1&index=3; jellyfish movement • http://www.youtube.com/watch?v=M9MMp7QX6e0&feature=PlayList&p=E9E1093124E2F9C9&playnext=1&index=2 polyp stage • http://www.youtube.com/watch?v=1mIo7YB5DKY&feature=PlayList&p=E9E1093124E2F9C9&playnext=1&index=1 more polyp

  13. Jellyfish bloom

  14. Cnidaria: hydrozoa • Portuguese Man-of-War are colonies of four kinds of highly modified polyps: feeding polyps, reproductive polyps, etc.. • Hydra • Hydra catching food: http://www.youtube.com/watch?v=Kukv0AtIVdU&feature=related • Hydra; http://www.youtube.com/watch?v=yqXkaZwiu6s&feature=related

  15. Anthozoa: flowering cnidarians • Sea anemone • Corals

  16. Reef evolution

  17. Reef types • Fringing reef Barrier reef atoll

  18. Ctenophora: close relatives to cnidarians • Comb jellies: secrete jelly instead of the stinging nematocysts of the cnidarians • Colloblasts are the jelly making cells

  19. Ctenophora: comb jellies

  20. Comb jellies • http://www.youtube.com/watch?v=G7WT81ukHZE

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