Chapter 11

A measure of how commonly a particular allele occurs in a population is known as the

• gene pool.

• allele frequency.

• mutation rate.

• phenotype.

The more genetic variation a population has, the more likely it is that some individuals will

• evolve.

• migrate.

• survive.

• mutate.

Genetic variation can arise from a random change in the DNA of a gene. This change is called a(n)

• mutation.

• gene flow.

• gene pool.

• allele.

The normal shuffling of alleles during meiosis results in

• mutations.

• hybridization

• reproduction.

• recombination.

Which term means the crossing of two different species that share common genes?

• mutation

• hybridization

• population

• recombination

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