Which statement best describes the mode of selection depicted in the figure showing individuals with intermediate phenotypes having higher fitness than those with extreme phenotypes?

• A. Directional selection favors one extreme phenotype over others.
• B. Stabilizing selection favors intermediate phenotypes over extremes.
• C. Disruptive selection favors both extreme phenotypes over intermediates.
• D. Balancing selection maintains multiple alleles at equal frequencies.

Answer: (B)

Verified step by step guidance

1. Understand the concept of natural selection: Natural selection is a process where individuals with certain traits have higher fitness and are more likely to survive and reproduce. Different modes of selection describe how traits are favored in a population.
2. Review the modes of selection: Directional selection favors one extreme phenotype, stabilizing selection favors intermediate phenotypes, disruptive selection favors both extreme phenotypes, and balancing selection maintains genetic diversity by keeping multiple alleles at similar frequencies.
3. Analyze the description provided in the problem: The figure depicts individuals with intermediate phenotypes having higher fitness than those with extreme phenotypes. This aligns with the definition of stabilizing selection.
4. Relate stabilizing selection to real-world examples: Stabilizing selection often occurs in traits like human birth weight, where intermediate weights are favored because they are less likely to result in complications compared to very low or very high weights.
5. Conclude that the correct answer is stabilizing selection, as it matches the description of intermediate phenotypes being favored over extremes.