Ch. 31 Biology

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Ch. 31 Biology
2010-11-23 15:20:19
Animal Origins Body Plans

Ch. 31 Biology
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  1. External appendages do what?
    Enhance locomotion
  2. Body segmentation?
    • Allow better control of movement.
    • May not be apparent externally
  3. What are the body cavity functions?
    • · Cushions suspended organs
    • · Acts as a hydrostatic skeleton against which muscles can work (soft-bodied animals)
  4. Coelomate?
    • mesoderm surrounds body cavity (coelom) and organs
    • Ectoprocts, nemerteans, phoronids, brachiopods, annelids, mollusks and arthropods
  5. Pseudocoelomate?
    mesoderm surrounds body cavity (pseudocoel) but not internal organs
  6. Acoelomate?
    • no fluid-filled body cavity
    • Flatworms
  7. What are the three types of body cavities?
    • Acoelomate
    • Pseudocoelomate
    • Coelomate
  8. Where is the body cavity located?
    between digestive tract and outer body wall
  9. Bilateral is?
    • Only 1 plane through midline divides animal into mirror-image halves.
    • *cephalization
  10. Radial are and is?
    • (cnidarians and ctenophores)
    • Any plane along central axis divides animal into similar halves.
  11. Aymmetrical are?
  12. What are the three types of symmetry?
    Asymmetrical, Radial, Bilateral
  13. Animal Body Plans Vary in 4 features. What are the four features?
    Symmetry, Body cavity, Body segmentation, External appendages
  14. Triploblastic animals divided into 2 groups. What are those two groups?
    protostomes and devitrosomes
  15. Characteristics of animals are?
    • · Muliticellular, heterotrophic eukaryotes
    • · Ingest food and digest internally
    • · Cells lack cell walls
    • · Most have tissues and capable of movement
    • · Most reproduce sexually (diploid stage usually dominates life cycle)
    • · In most, a small flagellated sperm (n) fertilizes a larger, nonmotile egg (n) to form a zygote (2n)
    • · Embryonic development regulated by Hox genes; includes cleavage and gastrulation