While all giraffes are tall they are not all the exact same height. Within a population, the height of each individual giraffe can vary. Scientists observe that over many generations the average height of the giraffe population is Increasing. They believe this in response to trees producing fewer leaves on lower branches, meaning the giraffes' main food source is higher up.

What kind of selection is this an example of?

(1 point)

Stabilizing Selection

Directional Selection

Disruptive Selection

Directional Selection and Disruptive Selection

1 answer

This is an example of Directional Selection. Directional selection occurs when individuals with a trait at one extreme of a phenotypic range have greater fitness than individuals with a trait at the opposite extreme. In this case, taller giraffes have a survival advantage because they can reach food sources that are becoming less accessible to shorter giraffes. As a result, over generations, the average height of the giraffe population increases.