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13 Cards in this Set
- Front
- Back
What are 2 reasons a species may be absent from a suitable habitat?
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Historical reasons - Dispersal (i.e. not introduced there yet)
Habitat selection |
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Define:
Dispersal |
Movement of organisms or propagules(e.g. seeds)
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Dispersal is both a _____ and a _____ process.
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ecological
genetic |
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What are the 3 modes of Dispersal that Ecologists recognize?
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1 - Diffusion dispersal
2 - Jump dispersal (can be human assisted) 3 - Secular dispersal |
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Define and give an example (from lecture):
Diffusion dispersal |
The gradual movement across suitable habitat for a period of several generations.
EXA: California Sea Otter |
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Define and give an example (from lecture):
Jump dispersal |
Movement of long distances over unsuitable habitat. Happens for an organisms lifetime.
EXA: Zebra mussel (was human assisted) *Also was the way that islands were colonized |
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Define and give an example (from lecture):
Secular dispersal |
Diffusion over ecological time, e.g. from continental drift.
EXA: Antarctic Beech species |
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The colonization of islands likely occurred from what type of dispersal?
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Jump dispersal
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Define:
Vagility |
The ability of an organism to move about freely and migrate
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What are 2 important variables in dispersal?
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1 - Barriers
2 - Vagility |
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What is the "Tens Rule"?
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Of all introductions of organisms to a new habitat, only 10% will survive.
Also, of those 10%, 10% will become pests. |
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What are 2 approaches to studying habitat selection?
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1 - Proximal approach
2 - Ultimate or Evolutionary approach |
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What are 2 examples of dispersal on the "Local Scale"?
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1 - Krakatau (dispersal of animals back into the environment after explosion)
2 - Introductions (human induced) and the "Tens Rule" |