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13 Cards in this Set
- Front
- Back
Why is diversity higher as you get to the equator? |
The climate: the cold slows down the chemical reactions by the poles. There is more sugar produced in the equator |
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in tropics.. |
-Main way to survive is competition -low competition, low rates of reproduction |
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reasons for high genetic diversity |
-old population -frequent immigration -many genetically diverse founders -environmentally allows for survival of many alleles |
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reasons for low genetic diversity |
-young population -immigration lacking or rare -few founders (or genetically similar founders) -natural selection allows only a few alleles to persist |
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Loss of alleles |
- genetic drift -natural selection -founder effect & genetic bottleneck -non-random breeding (includes inbreeding) |
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Genetic drift (or allelic drift)
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-is the change in the frequency of a gene variant (allele) in a population due to random sampling of organisms.
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Natural selection
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-is the gradual process by which heritable biological traits become either more or less common in a population as a function of the effect of inherited traits on the differential reproductive success of organisms interacting with their environment. It is a key mechanism of evolution.
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founder effect |
-loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population.
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population bottleneck
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-is an event that drastically reduces the size of a population
-may be caused by various events, such as an environmental disaster, the hunting of a species to the point of extinction, or habitat destruction that results in the deaths of organisms. |
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nonrandom mating
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- in which individuals with similar genotypes and/or phenotypes mate with one another more frequently than would be expected under a random mating pattern
-For example, it is common for individuals of similar body size to mate with one another. |
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gain alleles |
-mutations: make up alleles -gene flow: population --alleles gained --alleles lost ---loss more, more diversed |
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measurements of genetic variation among populations |
-within population variation (the difference between members of a single population -populations have a similar genetic variation |
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Homospiens |
-Africa - more genetic diversity in chimpanzees |