Question

In a population of mice, some individuals have brown fur and some have black fur. At present, both phenotypes are equally fit. What could happen to change the relative fitness of the two phenotypes of the population? For example, what could cause individuals with brown fur to show reduced fitness relative to individuals with black fur?

Answer 1

The relative fitness of different phenotypes in a population of mice can change due to environmental factors and the presence of intermediate phenotypes. A change in the environment that affects the camouflage of the mice can lead to a change in the relative fitness of different fur colors. Similarly, the presence of intermediate phenotypes that are less fit than the extremes can also affect the relative fitness of phenotypes.

Step-by-step explanation:

In a population of mice, the relative fitness of different phenotypes can change due to environmental factors and natural selection. For example, if the environment changes and the forest floor where the mice live becomes a different color, individuals with a fur color that blends better with the new environment may have a higher fitness.

Another factor that can change the relative fitness of phenotypes is the presence of intermediate phenotypes that are less fit than the extremes. In the example of mice at the beach, individuals with a medium-colored coat are at a disadvantage because they cannot blend in with either the sand or the grass, making them more likely to be eaten by predators.

Overall, the relative fitness of phenotypes can change based on how well they are adapted to their environment and how they compare to other phenotypes in terms of survival and reproduction.