Question

Stabilizing selection is the most common form of natural selection. It eliminates any extreme expression of a trait in a population of organisms when the average expression leads to a higher rate of survival. Stabilizing selection tends to A) decrease genetic sameness. B) decrease genetic diversity. C) increase the frequency of a rare allele. D) increase the frequency of two rare alleles.

Answer 1

B) decrease genetic diversity
Genetic Diversity refers to vast differences in genetic makeup (genotype) and thus often phenotype as well. The more that extreme genes/traits are excluded in survival and/or reproduction, leading to stabilizing selection, then the more genetically "same" or similar the population will evolve to long-term. Similarity is the opposite of diversity. Thus A) is dead wrong, B) is accurate, and both C) & D) are incorrect because "rare" means not common or "extreme." And extreme traits are exactly what decrease through stabilizing selection.
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