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15 Cards in this Set
- Front
- Back
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genetic drift
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big impact on small generations
-the smaller the gereration is the farther the law os probablilty predict |
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how does genetic drift take place?
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individuals that cary a particular allele may leave more descendant than other individuals just by CHANGE
over time a series of change occurences of this type can cause an allels to become more common a population |
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Founder's effect
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situation in which allele frequencies change as a result of the migration of a small subgroup of a population
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genetic drift...
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can affect a small population
-if 5 animals are there and one dies, 1/5 of its genes are gone, but if there were 500 brids and one died if is not as big of a deal |
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Hardy Weinberg
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states that allele frequencies in a popualtion wil remain constant unless one or more factors cause those frequencies to change
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genetic equilibrium
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the situation in which an allele frequency remains constant
-if allele frequencies do not change, the population will nto evolve |
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FIVE CONDITIONS require genetic equilibrium to be maintained
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one: random mating
two: the population must be very large 3: no omvement into or out of population 4: no mutations 5: no natural selection |
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Random Mating
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all memevers of the popoulation msuit have an equal opportunity to produce offspring
-ensures that each individual has equal chance of passing on alleles |
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large population
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genetic drift has less effect
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no movement in or our of the population
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the popualtions gene pool must by kept together and separate from tother gene pools b/c bring new alleles
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no mutations
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if they do new alleles may be introduced
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no natural selection
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all genotypes in the population have equal probabilties of survival and reporduction
no phenotype can hae a selective advantage over another |
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geographic isolation
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two populations are separated by geographic barriers suchs as rivers, mountains, ore bodies of water
-squirrels because they separate physically but they all have a common ancestor |
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temporal isolation
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two or more species reproduce at different times
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behavioral isolation
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occurs when two populations are capable of interbreeding but have differneces in courship rituals or other types of behavior
-meadowlarks |
