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Invertebrates

Invertebrates. Chapter 33. Most animals - invertebrates - do not have backbone. http://www.edsci-affiliates.com/images/invertebrates_divider.jpg. 1 Phylum Porifera. Sponges - lack nerves and muscles; sessile (non-motile). Most marine, live in water.

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Invertebrates

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  1. Invertebrates Chapter 33

  2. Most animals - invertebrates - do not have backbone.

  3. http://www.edsci-affiliates.com/images/invertebrates_divider.jpghttp://www.edsci-affiliates.com/images/invertebrates_divider.jpg

  4. 1Phylum Porifera • Sponges - lack nerves and muscles; sessile (non-motile). • Most marine, live in water. • Most hermaphrodites - each individual produces sperm and eggs. • Can regenerate lost parts.

  5. http://www.gcb.vic.gov.au/gallery/SEA%20SPONGE,%20PORIFERA.jpghttp://www.gcb.vic.gov.au/gallery/SEA%20SPONGE,%20PORIFERA.jpg

  6. Sponges perforated with holes so water can flow through them (suspension-feeding) • Water drawn through pores into central cavity (spongocoel) and flows out through larger opening (osculum)

  7. 2Phylum Cnidaria • 1st organisms to have true tissues. • Basic body plan - sac with central digestive compartment (gastrovascular cavity) • Jellyfish, corals, sea anemones, and hydras. • Have nerve nets - very primitive nervous systems that move towards stimuli.

  8. 2 body plans in cnidarians. • 1Polyp stage - sessile; some live whole life this way. • 2Medusa stage - cnidarian can swim freely. • Can move through both stages during lifetime.

  9. http://library.thinkquest.org/26153/marine/sketch/613.jpg

  10. Cnidarians have nematocysts - stinging cells. • Phylum Cnidaria divided into 3 major classes: Hydrozoa (hydra), Scyphozoa (true jellyfish), and Anthozoa (sea anemones). • Cnidarians - carnivores - use tentacles to push food into gastrovascular cavity.

  11. 3Phylum Ctenophora • Comb jellies named for fused cilia. • Resemble medusa stage of cnidarians. • No stinging cells present.

  12. 4Phylum Platyhelminthes • Flatworms, both parasitic and non-parasitic. • Flatworms have mesoderm - middle layer of tissues - makes them bilateral.

  13. http://www.waterworxbali.com/Images/Photos/Large/pseudoceros-ferrugineus.jpghttp://www.waterworxbali.com/Images/Photos/Large/pseudoceros-ferrugineus.jpg

  14. Gastrovascular cavity with only 1 opening; absorb materials across tissue. • Flatworms are divided into four classes: Turbellaria, Monogenia,Trematoda (flukes), and Cestoidea (tapeworms).

  15. Turbellaria http://en.wikipedia.org/wiki/Turbellaria

  16. Trematoda http://en.wikipedia.org/wiki/Trematodes

  17. Cestoidea http://www.saudeanimal.com.br/imagens/platelmintos.jpg

  18. Planaria - scavengers found in ponds. • No organs specialized for circulation or respiration; exchange gases across membranes. • Have eyespots for detecting light and lateral flaps for smell. • Nervous systems more advanced than cnidarians; reproduce asexually through regeneration (can sexually reproduce).

  19. Planaria

  20. Trematodes parasites with suckers to attach to victims. • Blood fluke - parasite of humans. • Tapeworms have suckers and hooks on head; anchor worm in digestive tract of host.

  21. Blood fluke

  22. 5Phylum Rotifera • Rotifers - complete digestive tract with separate mouth and anus. • Internal organs in pseudocoelom - body cavity not completely lined with mesoderm. • Functions as circulatory system -nutrients dissolved in cavity. • Have hydrostatic skeleton - movement.

  23. http://planktonweb.ifas.ufl.edu/Asplanchna.jpg

  24. Some rotifers exist only as females that produce more females from unfertilized eggs - parthenogenesis.

  25. 6Phylum Mollusca • Snails, slugs, clams, squid, and octopus. • Mollusks soft-bodied animals - most protected by hard shell of calcium carbonate. • All have similar body plan with muscular foot (locomotion), visceral mass with most of internal organs, and mantle.

  26. http://sps.k12.ar.us/massengale/clip0051.jpg

  27. Use radula to feed - allows them to scrape up food. • Most mollusks have separate sexes. • 4 common classes - Polyplacophora (chitons), Gastropoda (snails and slugs), Bivalvia (clams, oysters, and other bivalves), Cephalopoda (squids, octopuses, and nautiluses).

  28. Chiton

  29. http://cache.eb.com/eb/image?id=65301&rendTypeId=4 Gastropod

  30. http://www.marinefoundation.org/mussels_600.jpg Bivalves

  31. Cephalopod http://home.earthlink.net/~snailstales/cephalopods.jpg

  32. Gastropods have shells that they can retreat into (means stomach-foot) • Lining of mantle acts like lungs - allows them to live on land (garden snails and slugs).

  33. Bivalves - 2-shelled - clams, oysters, mussels, and scallops. • Most bivalves - suspension feeders, trapping fine particles in mucus that coats gills. • Usually sessile - cannot move during lifetime.

  34. Cephalopods have reduced shell and include nautilus, squid, and octopus. • Nautilus - external shell. • Have well-developed nervous system with complex brain and well-developed sense organs. • Cephalopods have closed circulatory system.

  35. Nautilus

  36. 6Phylum Annelida • Annelids - segmented worms. • Digestive system - pharynx, esophagus, crop, gizzard, and intestine. • Closed circulatory system with 5 chambers act as heart to pump blood.

  37. http://www.inhs.uiuc.edu/~sjtaylor/cave/cave_olig.jpg

  38. Each segment - pair of excretory tubes, (metanephridia) - remove wastes from blood and coelomic fluid exits through pores. • Brainlike pair of cerebral ganglia lie above and in front of pharynx. • Some earthworms reproduce asexually (regeneration), also reproduce sexually.

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