G 11 - 18.2 Evolution as Genetic Change

What is the effect of natural selection on single-gene traits?

• It only affects polygenic traits.

• It causes no change in allele frequency.

• It increases the frequency of all phenotypes.

• It changes the frequency of alternative phenotypes over time.

What is genetic drift?

• A process that increases genetic variation.

• A change in allele frequency due to random sampling.

• A type of natural selection.

• A method of artificial selection.

Which of the following describes stabilizing selection?

• Equal fitness across all phenotypes.

• No change in phenotype frequencies.

• Higher fitness for individuals at the center of the curve.

• Higher fitness at the extremes of the phenotype curve.

What is the bottleneck effect?

• A change in allele frequency due to migration.

• A reduction in population size leading to a change in allele frequency.

• A type of directional selection.

• An increase in genetic diversity.

What does directional selection favor?

• All individuals equally.

• Individuals at one end of the phenotype curve.

• Individuals at both extremes of the phenotype curve.

• Individuals at the center of the phenotype curve.

What is the founder effect?

• A change in allele frequency due to a large population.

• A change in allele frequency following a small subgroup's migration.

• A type of stabilizing selection.

• A process that eliminates genetic variation.

Which type of selection results in two or more contrasting phenotypes?

• Directional selection.

• Stabilizing selection.

• Genetic drift.

• Disruptive selection.

What happens to allele frequencies during genetic drift?

• They remain constant.

• They can change randomly.

• They are influenced by natural selection.

• They always increase.

What is the primary outcome of natural selection?

• Adaptation of populations to their environment.

• Increased genetic diversity.

• Stabilization of all traits.

• Random changes in allele frequencies.

What is the significance of the phrase 'higher fitness' in the context of natural selection?

• It is synonymous with genetic drift.

• It means having more offspring than others.

• It indicates a larger body size.

• It refers to the ability to survive and reproduce.