If smaller individuals of your species had higher fitness than larger individuals, what type of selection would you expect to see?
a. Directional
b. Stabilizing
c. Disruptive
d. Balancing
To determine the type of selection that would occur in this scenario, we need to understand the three types of natural selection:
1. Directional Selection: This occurs when individuals at one extreme of a trait spectrum have higher fitness compared to individuals at the other extreme. Over time, the population shifts towards the more advantageous trait. This could happen if, for example, larger individuals had higher fitness than smaller individuals.
2. Stabilizing Selection: In this type of selection, individuals with intermediate trait values have higher fitness compared to those with extreme values. This leads to a reduction in the population's variation over time. Stabilizing selection favors the maintenance of the existing average trait.
3. Disruptive Selection: Disruptive selection occurs when individuals with extreme trait values have higher fitness than individuals with intermediate values. This can result in the formation of distinct subgroups within the population representing each extreme trait.
In the given scenario, where smaller individuals have higher fitness than larger individuals, we would expect to see disruptive selection. This is because individuals at both ends of the size spectrum (smaller and larger) have higher fitness, while those with intermediate sizes have lower fitness. This can lead to the formation of two distinct groups – one consisting of smaller individuals with high fitness and another consisting of larger individuals with high fitness.
Therefore, the correct answer is c. Disruptive.