Birds with average-size wings survived a severe storm more successfully than other birds in the same population with longer or shorter wings. if severe storms occur regularly, then over time, one should expect these storms to bring about __________.
The correct answer is stabilising selection. This is selection that favours an average trait value. It is thought that this sort of selection is very common as traits among most animals do not appear to change drastically over time. Stabilising selection selects against the extreme traits, and leads to a decrease in genetic diversity by favouring the average phenotypes.
