Animal Diversity and Evolution


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Animal Diversity and Evolution

  1. 1. Animal Diversity I
  2. 2. Animal characteristics      Distinct set of genes that uniquely control body plans different from fungi and plant body plans Heterotrophs Develop from a fertilized egg Internal means to digest food Motile in at least one stage of life cycle
  3. 3. Phylum Porifera Sponges       Spicules: gives structure and is a form of defense to predators Mostly asymmetrical Sessile (immobile) adults, free-swimming larvae 2 cell layers:  Outer cell layer is the epidermal layer  Inner cell layer is lined with choanocytes  flagellated cells used to bring in food and water through ostia Brings food and water inside via ostia (filter feeder) Expels waste and water via osculum
  4. 4. Phylum Porifera Filter feeding in sponges
  5. 5. Phylum Porifera Observe slide of Grantia or Scypha
  6. 6. Phylum Cnidaria sea jellies, sea anemones, and corals  Two body forms, many show both forms during their lifecycle:      Sac-like gut with one opening (no anus)( Dead End digestive tract) Have radial symmetry Two cell layers (diploblastic):    Sessile polyp Motile larva and medusa Ectodermic layer Endoderm layer Stinging nematocysts along tentacles to capture prey and for defense
  7. 7. Phylum Cnidaria Nematocysts
  8. 8. Phylum Cnidaria Typical life cycle
  9. 9. Major Classes of Cnidarians  Hydrozoa   Scyphozoa   Hydroids (hydra-like), some are jelly-like True sea jellies Anthozoa   Includes corals and sea anemones Lack medusa phase, only polyps
  10. 10. Phylum Cnidaria Hydra: observe slide  Observe two tissue layers (diploblastic):     ectoderm endoderm Single opening for feeding and extruding waste No free-swimming medusa phase
  11. 11. Phylum Cnidaria Obelia: observe medusa and polyp slide medusa stage polyp stage
  12. 12. LOPHOTROCHOZOA      Lophophore of a brachiopod Organisms having a lophophore (a specialized tentacle structure) or have a trochophore larval form Protostomes: have mouth and anus, but mouth forms before the anus Bilateral symmetry Complete digestive tract (except Platyhelminthes) Three distinct cell layers (triploblastic):  Ectoderm, mesoderm, and endoderm Trochophore larva (annelids and mollusks)
  13. 13. Phylum Platyhelminthes Flatworms, planarians, flukes, and tapeworms    Only have one opening for digestive tract Can be parasitic, carnivorous, or herbivorous Advances include:   More specialized tissues Several, well-developed organ systems  Cephalization: development a head  Localization of sense organs  First group to have bilateral symmetry of
  14. 14. Phylum Platyhelminthes Diversity within Platyhelminthess  Flatworms     Mostly free-living: predators or scavengers (dead, organic matter) Many are brightly colored Cilia or muscular movement Planarians   Free-living: feed on small animals or scavenge Cilia for movement
  15. 15. Phylum Platyhelminthes Diversity within Platyhelminthes  Flukes  Parasitic in liver, lungs, bladder, or blood vessels of vertebrates  Primary host for adult fluke: vertebrate  Intermediate host for larvae: usually a snail  Tapeworms   Specialized parasites for life in intestine (predigested food) Attach to host by scolex (suckers & hooks)
  16. 16. Phylum Platyhelminthes Observe slide of liver fluke, Opisthorchis  Parasitic flatworm
  17. 17. Phylum Platyhelminthes Tapeworms
  18. 18. Phylum Annelida segmented worms, marine worms, earthworms, leeches  Advancements  Segments: repeating units  Hydrostatic skeleton: fluid filled cavity in which pressure can be changed to allow the animal to move  Setae (bristles) for movement  Simple diffusion for gas exchange (no respiratory system)  Well-developed digestive, circulatory, reproductive, and nervous systems
  19. 19. Phylum Annelida Class Polychaeta: bristle worms    Mostly live in marine environments Have many setae (bristles) that extend from their parapodia (appendages) Typically either filter feeders or carnivorous
  20. 20. Phylum Annelida Class Oligochaeta: earthworms       Found in terrestrial & freshwater habitats Herbivorous or detritivorous Few setae and no parapodia Hermaphroditic Observe prepared slide Dissect Lumbricus
  21. 21. Phylum Annelida Lumbricus (earthworm) dissection  Basic anatomy terms  Anterior: head end  Posterior: tail end  Dorsal: back  Ventral: belly  Pin anterior end to dissecting pan Cut body open along the anterior-posterior axis Separate body wall from animal and pin to dissecting pan Use water to flush body cavity   
  22. 22. Phylum Annelida Class Hirudinea: leeches    Live in marine, freshwater, and terrestrial habitats Leeches have no bristles and no parapodia Can be free-living (carnivorous) or parasitic
  23. 23. Phylum Mollusca chitons, snails, slugs, clams, octopus, squid, nautilus  Body plan  Muscular foot  Visceral mass: contains organs(digestive, circulatory, reproductive) and is protected by a hard outer shell  Mantle that secretes protective shell  Gills to obtain oxygen from water  Head with sensory structures  Very advanced in cephalopods
  24. 24. Phylum Mollusca Class Polyplacophora: chitons   Marine omnivores that scrape algae and other organisms with radula Clings tightly to rocks with foot
  25. 25. Phylum Mollusca radula
  26. 26. Phylum Mollusca Class Gastropoda: snails and slugs      Name means “stomach foot” Radula for feeding Glide by moving muscular foot Some slugs have aposomatic coloration (warning colors) Are either carnivorous or herbivorous
  27. 27. Phylum Mollusca Class Bivalvia: clams, mussels, scallops, oysters     2-part shell Foot used for anchoring and burrowing Do not have a head, radula, or eyes Use gills for oxygen and filter-feeding
  28. 28. Phylum Mollusca Class Cephalopoda: squid, octopus, nautilus      Name means “head foot” Lack outer shell (except nautilus) Uses modified mantle to jet through the water Use tentacles to capture prey Very complex sensory systems
  29. 29. Squid tentacle with hooks
  30. 30. ECDYSOZOA       Protostomes These organisms have an exoskeleton Must molt in order to grow Complete digest tract Bilateral symmetry Three distinct cell layers:    Ectoderm Mesoderm Endoderm
  31. 31. Phylum Nematoda Roundworms        Can be parasitic or free-living (carnivorous or herbivorous) One of the most widespread and diverse animal Complete digestive system, has a mouth and an anus False body cavity present  Filled with reproductive organs  No protective lining around organs, but some separation of organs Some parasites of plants and animals Observe prepared slide Dissect Ascaris
  32. 32. Phylum Nematoda Ascaris dissection   Use same techniques used for dissecting Lumbricus Make comparisons between the two dissected specimens
  33. 33. Phylum Arthropoda Chelicerates, myriapods, hexapods, and crustaceans  Arthropods united by having:  Segmentation   Exoskeleton   Basic body plan: head, thorax, abdomen Made of chitin, molt to grow     Used for feeding, movement, senses, and reproduction Spiders, mites, and ticks Subphylum Myriapoda   Shrimp, lobsters, barnacles, and relatives Subphylum Chelicerata  Jointed paired appendages  Subphylum Crustacea Millipedes and centipedes Subphylum Hexapoda  Insects and relatives
  34. 34. Phylum Arthropoda Subphyla of Arthropoda Crustacea: crayfish Chelicerata: tarantula Myriapoda: Hexapoda: beetle