Metozoan Diversity

  1. Hydrostatic Skeleton
    • Container for circulation of oxygen and nutrients and space where internal organs can move independently of each other
    • 1. liquid water is efficently incompressible at biologically relevant pressures
    • 2. a given amount of liquid water contains a constant volume, but the shape of the volume is free to vary
    • 3. Organisms can use muscles to transfer force from one part of the body to another and to change their shape
  2. Pseudocoelom
    Body cavity forms between endoderm and mesoderm layers (primary body cavity)
  3. Coelomates
    Tripoblasts witha coelom (sencondary body cavity)
  4. Acoelomates
    Tripoblasts that do not have a coelom
  5. Enterocoely
    • Coelm formed by evagination of gut
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  6. Schizocoely
    • Coelom formed by split in mesoderm
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  7. Mixocoel
    Primary and secondary body cavities
  8. Body Cavity
    • Internal fluid filled space located between ectoderm and endoderm
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  9. Segmental Symmetry or Segmentation
    • Body units repeated along a longitudital axis
    • A common form of symmetry in animals that:
    • 1. have complex or powerful body movements (eg annelids, arthopods, vertebrates)
    • OR
    • 2. benefit from having multiple reproductive systmes (eg tapeworms- Playhelminthes)
    • An evolutionary route to increasing a feature (size, complexity, number of muscles) without evolving totally new features
  10. Bilateral Symmetry
    • Two body units reflected across central (mid-saggital) plane
    • Dominant in animals that:
    • 1. are mobile and interact with the enviroment in one preferred orientation (anterior end)
    • 2. Have distinct ventral and dorsal surfaces
    • 3. Have a head where sense organs, brain, and (usually) central mouth are located (cephilization)
    • 4. are descendants from organisms with one or more of the above
  11. Radial Symmetry
    • Body units distributed around a central axis and/or reflected across multiple planes
    • Dominant form of symmetry in animals that:
    • 1. have no or little motility
    • 2. are filter feeds, sit and wait predators, or have food producing emdosymbionts
    • 3. have diffuse sense organs, uncentralized nervous systems, central mouth (no head, no brain)
    • 4. are descendants from ancestors with one or more of above
  12. Body Symmetry
    • Condition of having similar shapes or structures organized at or across a specific point, axis, or plane
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  13. Gastrulation
    • Series of cell movements that forms the three embryonic layers. Migration creates pore that opens to the outside
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  14. Radial Determinant clevage
    • orientation of mitotic axis to embryonic axis and orientation of cells to each other
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  15. Spiral Cleavage
    • Spiral cleavage
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  16. Traditional Themes for Organizing Metazoan Diversity
    • 1. Hiearchy of Fundamental Organization- tissues, organs, organ systems
    • 2. Early development- cleavage, determincy, gasturlation, developmental tissues
    • 3. Body Symmetry
    • 4. Body cavities and their development
  17. Characteristics of Metazoa
    Multicellularity- cells adhere together and differentiate to form mutually beneficial functions

    Heterotrophy-acquire organic carbon and nitrogen from consumption of other organisms

    Animal Moltility- active movement of the entire multicellular organism

    Colagen based extracellular matrix- cells bound together by collagen, a family of triple helical, coiled, fibrous proteins (eg basement membrane of epithelium); strong, elastic, resilient

    Early sequestration of germline cells- cells designed to produce gametes isolated early in development

    Hox genes-developmental regulatory genes (transcription factors) that specificy cell identity, arranged in linear clustors in a conserved sequence
  18. Metazoan Diversity
    Image Upload 8
Card Set
Metozoan Diversity
animal diversity