Question

What effect does each type of selection have on the mean and variance of the trait in the next generation if it is stabilizing

a) Increases mean, decreases variance
b) Increases mean, increases variance
c) Decreases mean, decreases variance
d) Decreases mean, increases variance

Answer 1

Stabilizing selection decreases genetic variance by favoring an average phenotype and eliminating extremes. Disruptive selection increases variance by favoring extreme phenotypes, and directional selection can change the mean and potentially increase variance.

Step-by-step explanation:

In biology, when discussing the effects of different types of selection on a population's genetic makeup, it is essential to understand how they impact trait distribution. Stabilizing selection favors the average phenotype and selects against extreme variations.

On the other hand, disruptive selection (also known as diversifying selection), where extreme phenotypes are favored over the intermediate, increases genetic variance by promoting a range of phenotypic diversity. Lastly, directional selection shifts the average phenotype toward one extreme, causing a change in the mean and potentially increasing the population's genetic variance if the shift exposes new phenotypic variations.