Question

In a population of mice, individuals with medium brown fur are less likely to be seen by predators than light brown and dark brown mice. What type of selection is this, and what would the distribution curve for the mouse population look like?

Answer 1

[AI-generated answer — Bot GPT 3.5]

This scenario describes stabilizing selection and would likely result in a normal distribution curve for the mouse population.

Stabilizing selection occurs when individuals with intermediate characteristics have a higher fitness compared to those with extreme characteristics. In this case, mice with medium brown fur have an advantage as they are less likely to be seen by predators. Light brown mice might be more visible, while dark brown mice could be easily spotted, making them more vulnerable to predation. Consequently, mice with medium brown fur have a higher survival rate, reproduce more successfully, and pass on their medium brown fur genes to the next generation.

Over time, this selection pressure against light and dark brown fur leads to a decrease in the frequency of these extreme fur colors in the population. As the population undergoes stabilizing selection, the distribution curve for the fur color would take on a characteristic bell-shaped or normal distribution.

The normal distribution curve would be centered around the intermediate fur color, which is medium brown in this case. The number of individuals with medium brown fur would be higher in comparison to light and dark brown individuals. Thus, the graph would show a peak in the middle representing the medium brown mice, gradually tapering off towards the light and dark brown ends.

Answer 2

stabilizing; a tall, narrow peak in the center of the graph?

Answer 3

[AI-generated answer — Bot GPT 3.5]

Apologies for the confusion in my previous response. You are correct; stabilizing selection would result in a tall, narrow peak in the center of the graph.

In stabilizing selection, individuals with intermediate traits are favored over those with extreme traits. This means that mice with medium brown fur, being less likely to be seen by predators, have a higher fitness compared to both light and dark brown mice. As a result, the frequency of medium brown individuals increases in the population, while the frequency of light and dark brown individuals decreases.

If we were to graph the distribution of fur color in the mouse population, it would indeed have a tall, narrow peak in the center. This peak represents the high frequency of medium brown mice, which have the highest fitness. The graph would then gradually taper off towards the light and dark brown ends, indicating the lower frequencies of individuals with those fur colors. So, the distribution curve would resemble a normal distribution with a tall peak at the center.