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11 Cards in this Set
- Front
- Back
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What is reproductive fitness?
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reproductive success
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Give at least 3 examples of natural selection in the wild.
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Industrial melanism in moths
Sickle cell anemia in humans drug resistance in bacteria |
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what are the 3 types of natural selection?
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directional - selecting for 1 extreme phenotype
stabilising - selecting for average Disruptive - selecting for extremes |
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what is kin selection?
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protecting relatives - protect the genes
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what is the founder effect?
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loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population. So new population may be distinctively different, and in extreme cases may lead to speciation and subsequent evolution of new species
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what is the founder effect a special case of?
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genetic drift
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what are the dangers to the small population in the founder effect?
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small so higher sensitivity to genetic drift, reduced genetic variation and higher levels of inbreeding leading to reduced gene pool
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what is genetic drift?
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change in the relative frequency in which an allele occurs in a population due to random sampling and chance
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What is fixation?
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change in a gene pool from a situation where there existed at least 2 alleles to a situation where only 1 of the alleles remains
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what can happen to rare alleles in the original population in the founder effect?
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can move to 2 extremes - usually lost, but may survive and within a few generations become much more dispersed thorughout the population - so frequency of recessive alleles may increase so possible increase in recessive illnesses
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what is a population bottleneck?
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a significant population of species is killed or otherwise prevented from reproducing
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