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Multiple Choice
Which of the following evolutionary forces is most likely to decrease genetic variation between populations?
A
Mutation
B
Genetic drift
C
Natural selection
D
Gene flow
Verified step by step guidance
1
Understand the concept of genetic variation: Genetic variation refers to the diversity in gene frequencies within and between populations. It is influenced by evolutionary forces such as mutation, genetic drift, natural selection, and gene flow.
Define gene flow: Gene flow, also known as migration, is the transfer of genetic material between populations. It occurs when individuals from one population move to another and interbreed, introducing new alleles into the recipient population.
Analyze the impact of gene flow on genetic variation: Gene flow tends to homogenize genetic differences between populations by mixing alleles. This reduces genetic variation between populations while increasing genetic variation within populations.
Compare gene flow with other evolutionary forces: Mutation introduces new genetic variation within populations but does not directly decrease variation between populations. Genetic drift, especially in small populations, can lead to random changes in allele frequencies, increasing differences between populations. Natural selection can either increase or decrease genetic variation depending on environmental pressures, but it does not inherently homogenize populations like gene flow does.
Conclude why gene flow decreases genetic variation between populations: Gene flow counteracts the effects of genetic drift and local adaptation by spreading alleles across populations, making them more genetically similar over time.