1 / 56

Chapter 29

Chapter 29. The Animal Kingdom: The Protostomes. Characteristics of protostome coelomates Spiral cleavage Determinate cleavage Development of the mouth from the blastosphore. Characteristics of protostome coelomates, cont. Coelom is a fluid-filled cavity lined with mesoderm

afoy
Download Presentation

Chapter 29

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 29 The Animal Kingdom: The Protostomes

  2. Characteristics of protostome coelomates • Spiral cleavage • Determinate cleavage • Development of the mouth from the blastosphore

  3. Characteristics of protostome coelomates, cont. • Coelom is a fluid-filled cavity lined with mesoderm • Evolution of the coelom permitted many innovations, including • Tube-within-a-tube body plan • Hydrostatic skeleton

  4. Characteristics of protostome coelomates, cont. • Coelom provides space for development of internal organs and gonads • Coelom helps transport materials and protects internal organs

  5. Protostome coelomates include two main branches • Lophotrochozoa • Ecdysozoa

  6. Lophotrochozoa • Platyhelminthes • Nemerteans • Mollusks • Annelids • Lophophorate phyla • Rotifers

  7. Longitudinal section of rotifer

  8. Ecdysozoa • Nematodes • Arthropods

  9. Characteristics of phylum Nemertea • Proboscis • Reduced coelom: rhynchocoel • Tube-within-a-tube body plan • Complete digestive tract • Mouth with anus

  10. Lateral view of a typical nemertean

  11. Characteristics of phylum Platyhelminthes • Acoelomate • Bilateral symmetry • Cephalization • Three definite tissue layers

  12. Characteristics of phylum Platyhelminthes, cont. • Well-developed organs • Many are hermaphrodites • Ladder-type nervous system • Ganglia • Protonephridia

  13. Phylum platyhelminthes • Turbellaria • Free-living flatworms including planarians • Trematoda and Monogenea • Parasitic flukes • Cestoda • Parasitic tapeworms

  14. The common planarian, Dugesia Internal structure LM of a living planarian, Dugesia dorotocephala

  15. Parasitic flukes and tapeworms typically have • Suckers or hooks • Complicated life cycles with intermediate hosts • Large numbers of eggs

  16. Life cycle of the blood fluke

  17. Adaptive advantages of cephalization • Beginnings of cephalization, increases the effectiveness of a bilateral animal to find food and detect enemies

  18. Distinguishing characteristics of phylum Mollusca • Soft bodied animals usually covered by a shell • Ventral foot for locomotion • Mantle covering the visceral mass

  19. Distinguishing characteristics of phylum Mollusca, cont. • Open circulatory system (except cephalopods) • Metanephridia • Radula • Ciliated trochophore larva

  20. Four classes of Phylum Mollusca • Polyplacophora • Gastropoda • Bivalvia • Cephalopoda

  21. Class Polyplacophora • Shells consist of eight overlapping plates • Chitons

  22. Class Polyplacophora

  23. Class Gastropoda • Body undergoes torsion • Snails • Slugs • Relatives

  24. Class Gastropoda

  25. Embryonic torsion in a gastropod

  26. Class Bivalvia • two-part, dorsally-hinged shell encloses body • Aquatic clams • Scallops • Oysters

  27. Class Bivalvia

  28. Class Cephalopoda • Active, predatory swimmers • Tentacles surround the mouth located in the large head • Squids • Octopods • Nautilus

  29. Class Cephalopoda

  30. Distinguishing characteristics of phylum Annelida • Segmented worms • Aquatic worms • Earthworms • Leeches

  31. Distinguishing characteristics of phylum Annelida, cont. • Conspicuously long bodies • Internal and external segmentation • Large compartmentalized coelom serves as a hydrostatic skeleton

  32. Phylum Annelida has three classes • Polychaeta • Oligochaeta • Hirudinea

  33. Class Polychaeta • Marine worms with • Parapodia for locomotion and gas exchange • Setae on the parapodia

  34. Class Oligochaeta • Earthworms • A few short setae per segment • Body is divided into more than 100 segments separated internally by septa

  35. Body plan of an earthworm

  36. Class Hirudinea • Leeches • No setae • No appendages • Parasitic leeches have suckers for holding onto their host

  37. Distinguishing characteristics of phylum Nematoda • Pseudocoelomates • Bilateral symmetry • Three tissue layers • Complete digestive tract • Body covered by cuticle

  38. Parasitic nematodes in humans • Ascaris • Hookworms • Trichina worms • Pinworms

  39. The roundworm Ascaris • Longitudinal section • (b) Cross section (b) (a)

  40. Distinguishing characteristics of phylum Arthropoda • Segmented animals with • Paired, jointed appendages • Armor-like exoskeleton of chitin • Molting is necessary for growth

  41. Distinguishing characteristics of phylum Arthropoda, cont. • Open circulatory system • Dorsal heart that pumps hemolymph

  42. Distinguishing characteristics of phylum Arthropoda, cont. • Aquatic forms have gills • Terrestrial forms have either tracheae or book lungs • Trilobites are extinct marine arthropods covered by a hard, segmented shell

  43. Subphylum Myriapoda • Unbranched appendages and a single pair of antennae • Class Chilopoda • Class Diplopoda

  44. Trilobite Dorsal view Ventral view

  45. Subphylum Chelicerata • Body consists of a cephalothorax and abdomen, with six pairs of jointed appendages, four pairs of which serve as legs • Merostomes • Arachnids

  46. Subphylum Chelicerata, cont. • First pair of appendages are chelicerae • Second pair are pedipalps • No antennae • No mandibles

  47. Subphylum Crustacea • Lobsters • Crabs • Shrimp • Pillbugs • Barnacles

  48. Anatomy of the lobster

More Related