Why is it thought that the majority of natural selection is stabilizing selection?

• A. Because stabilizing selection favors average phenotypes, reducing extremes and maintaining the status quo in populations.
• B. Because stabilizing selection increases genetic variation by favoring rare alleles.
• C. Because stabilizing selection eliminates all genetic diversity within a population.
• D. Because stabilizing selection leads to rapid evolutionary change by favoring new mutations.

Answer: (A)

Verified step by step guidance

1. Understand the concept of stabilizing selection: Stabilizing selection is a type of natural selection that favors intermediate or average phenotypes, reducing the prevalence of extreme traits in a population. This helps maintain the status quo and promotes population stability over time.
2. Analyze the first option: 'Because stabilizing selection favors average phenotypes, reducing extremes and maintaining the status quo in populations.' This aligns with the definition of stabilizing selection, as it describes how this process reduces extremes and maintains balance in the population.
3. Evaluate the second option: 'Because stabilizing selection increases genetic variation by favoring rare alleles.' This is incorrect because stabilizing selection typically reduces genetic variation by eliminating extreme phenotypes, not by favoring rare alleles.
4. Evaluate the third option: 'Because stabilizing selection eliminates all genetic diversity within a population.' This is also incorrect because stabilizing selection reduces extremes but does not completely eliminate genetic diversity; some variation is still maintained in the population.
5. Evaluate the fourth option: 'Because stabilizing selection leads to rapid evolutionary change by favoring new mutations.' This is incorrect because stabilizing selection does not lead to rapid evolutionary change; instead, it maintains the status quo by favoring existing average phenotypes rather than new mutations.