Genetic drift is a major source of evolutionary change in small populations. Why

Question

Genetic drift is a major source of evolutionary change in small populations. Why is this so? A cell contains two homologous sets of chromosomes. Identify each statement as true or false. Correct each false statement to a true statement. The cell that contains these homologous sets of chromosomes must be diploid. Each homologous pair of chromosomes was formed by DNA replication of a single chromosome. Barring mutation, the two chromosomes in a homologous pair must be identical. One member of each homologous pair is from the maternal family line; the other member is from the paternal family line. Do X and Y chromosomes cross-over during meiosis? Explain.

Explanation / Answer

Genetic drift is a major source of evolutionary change insmall populations because the allelic frequencies are impactedmore. It occurrs by chance. For example, a bunch of geese ina small flock might decide to go away to an island andmake their own little colony, never coming back. This reduces thenumber of possible mates in the mainland group; meanwhile themigratory group can interbreed and over time form a new type ofgoose. This is called the founder effect. There is another factorcalled the bottleneck effect. Say I kill all of the fat squirrelsin my neighborhood. That would put a new advantage for the skinnysquirrels because they wouldn't get killed. So eventually, sincemost of the live squirrels are now skinny, they will reproduceskinny squirrels and eventually the fat squirrels will soon not beprominent in the area.

C is true.

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