How can three different types of males evolve and be maintained within a single population according to the principles of natural selection?

• A. By random genetic drift alone, which always maintains multiple male types indefinitely.
• B. Through frequency-dependent selection, where the fitness of each male type depends on its frequency relative to others.
• C. Due to the absence of any selective pressures acting on male traits.
• D. Because all mutations automatically result in equal fitness among male types.

Answer: (B)

Verified step by step guidance

1. Understand the concept of natural selection: Natural selection is the process by which traits that confer a survival or reproductive advantage become more common in a population over generations. Traits that reduce fitness tend to be eliminated.
2. Learn about frequency-dependent selection: Frequency-dependent selection occurs when the fitness of a phenotype depends on its frequency relative to other phenotypes in the population. For example, rare phenotypes may have an advantage because they are less likely to be targeted by predators or competitors.
3. Apply frequency-dependent selection to the problem: In the case of three different male types, frequency-dependent selection can maintain all three types if their fitness varies depending on their relative abundance. For instance, one male type might be more successful when rare, while another might thrive when common.
4. Rule out other options: Random genetic drift alone does not maintain multiple male types indefinitely, as it is a stochastic process that can lead to the loss of genetic variation over time. Similarly, the absence of selective pressures or the assumption that all mutations result in equal fitness does not align with the principles of natural selection.
5. Conclude that frequency-dependent selection is the mechanism: The correct answer is that frequency-dependent selection allows the coexistence of multiple male types by ensuring that their fitness depends on their relative frequency in the population, maintaining diversity over time.