NATURAL SELECTION IN POPULATIONS

What is the observable change in the allele frequencies of a population over time called?

• selection

• microevolution

• distribution

• recombination

Natural selection that changes the distribution of a trait to favor one extreme phenotype is called

• disruptive selection.

• stabilizing selection.

• normalizing selection.

• directional selection.

In stabilizing selection, what occurs in a population?

• The population shifts toward one of two extreme phenotypes.

• Both extreme phenotypes shift toward the middle.

• The intermediate phenotype becomes more common.

• The intermediate phenotype becomes rare.

A population that is not undergoing natural selection displays what type of distribution?

• normal

• disruptive

• directional

• stabilizing

In a population of birds, intermediate beak size is selected against, and both very small and very large beak sizes are favored. What type of selection is this an example of?

• directional

• disruptive

• normal

• stabilizing