patterns of bio diversity

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  1. what are diversity gradients
    the # of species in an area may vary based on various gradients . ex latitude
  2. what is the evolutionary speed hypothesis
    • diversity is affected by length of un-interupted evolutionary time
    • - ex. tropics have been less disturbed in recent history than temperate zones
  3. What is the geographic area hypothesis?
    the larger an area is, the more diverse habitats and thus species possible

    -relationship between area and richness is not always supported. boundaries hard to define
  4. patterns of bio diversity: what are interspecific reactions
    higher diversity due to greater inter-specific competition & predation rates
  5. What is the ambient energy hypothesis
    • higher available energy generates/maintains higher global diversity gradients
    • -climate dictates available energy (light, temp, water)
    • -closer to equator = more light, heat, moisture
  6. what is the intermediate disturbance hypothesis
    • disturbance is a factor that affects local species diversity
    • -states that if communites exist i equilibrium (no change from coming going)
    • -competition dictates taht one or two competative species should dominate.
    • -disturbance knocks communities out of equilibrium
  7. what can act as a disturbance?
    • predation
    • herbivory
    • change in physical factors (temp,light, etc)
    • catastrophe (fire,flood,etc)
  8. disturbance allows
    • allows other species to get a foothold(predator mediated competition)
    • to much disturbance is NOT a good thing
    • too little disturbance isnt good = competative exclusion
    • intermediate disturbance = highest species diversity
  9. General physical structure -
    communites are also characterized by general physical form
    what is the community vertical structure?
    • based on growth form of plants
    • - size of plants, variation in branching heights, leaf density. this is associated with vertical production of light.
    • Provides framework for animals, who adapt to certain structures
  10. Species within communities are constrained by their f________ niche

    the range of t_________ exhibited by species influences their p_______ in a community
    Fundamental niche

    tolerances, presence
  11. what is succession?
    • the universal process of directional change in vegetation over time
    • -progressive change in groups of species in an area.. with one group replacing a previous group
  12. give an example of how a forest succession might happen
    • clear cut->shrubs/saplings->pole woods-> mature forest
    • only way to go backward is disturbance
  13. what are the two types of succession
    primary succession and secondary succession
  14. when does secondary succession occur?
    give an ex.
    • after small-scale disturbances
    • - agricultural field abandoned, fire, treefall
  15. when does primary succession occur?
    give an ex.
    • occurring after large-scale disturbance
    • -succession of a new sterile area
    • -mt st helens ash sterilized area
  16. which happens faster, primary succession or secondary succession
    • secondary
    • primary much slower than secondary
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patterns of bio diversity
2013-05-13 05:00:34

ecology 457
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