Polydactylism occurs _______.
According to the theory of island biogeography, those islands that are further isolated from the mainland and other islands would be expected to have _______.
How do natural disasters contribute to genetic drift?
A natural disaster can randomly kill many individuals, leaving only a small group of survivors. Because the survivors may not represent the original population’s genetic makeup, allele frequencies can change by chance. This random change is genetic drift.
After hunting by European settlers, the bison population of 60 million was reduced to _______ of its original size.
Which of the following has not resulted in the decline of cheetah populations?
Bottleneck events lead to _______.
Explain how the Amish are an example of the founder effect.
The Amish descended from a relatively small group of founders who carried only a sample of the genetic variation in the larger population. Some alleles were more common in that group, and relative isolation and marriage within the community allowed those alleles to become more frequent. This is the founder effect.
Explain how a bottleneck event can enrich recessive traits in the genetics of a population.
A bottleneck leaves a small, chance sample of the original population. If recessive alleles are overrepresented among the survivors, their frequency can rise; the smaller population and increased inbreeding also make it more likely that individuals inherit two copies and express the recessive trait.
Explain why a population of Mouflon in the Indian Ocean descended from only two individual that had not experienced a loss of genetic diversity was so surprising to scientists.
Scientists expected the population to have low genetic diversity because only two individuals founded it, carrying only a small sample of the alleles present in the original population. Its substantial retained diversity was therefore unexpected.
Explain why the crossbreeding of bison and cattle is both a benefit and hindrance to conservation efforts aimed at protecting bison genetic diversity.
Crossbreeding with cattle can add genetic variation and may reduce inbreeding in a small population. However, cattle genes can enter the bison gene pool and dilute the distinctive genetic makeup of bison. It may therefore help genetic diversity in one sense while hindering efforts to preserve genetically pure bison.
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