G11 - 18.2 Evolution as Genetic Change

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

• It changes the frequency of alternative phenotypes.

• It stabilizes the population.

• It increases genetic drift.

• It causes no change in allele frequency.

What is genetic drift?

• A form of natural selection.

• A change in allele frequency due to random events.

• A process that stabilizes allele frequencies.

• A method of artificial selection.

Which of the following describes stabilizing selection?

• No change in phenotype distribution.

• Equal fitness across all phenotypes.

• Higher fitness near the center of the phenotype 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 method of selecting for specific traits.

• A type of genetic equilibrium.

What does directional selection favor?

• Individuals at the center of the curve.

• All individuals equally.

• Individuals at one end of the curve.

• Individuals at both ends of the 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 method of genetic engineering.

Which selection type has higher fitness at both extremes?

• Genetic drift.

• Disruptive selection.

• Stabilizing selection.

• Directional selection.

What happens to allele frequencies in polygenic traits over time?

• They stabilize the population.

• They only affect single-gene traits.

• They change the position or shape of the distribution.

• They remain constant.

What is required to maintain genetic equilibrium?

• Directional selection.

• Genetic drift.

• Random mating and no selection.

• High mutation rates.

What is the primary focus of natural selection?

• To increase genetic variation.

• To favor individuals with higher fitness.

• To stabilize allele frequencies.

• To eliminate all genetic drift.