Question 1

Which of the following best describes stabilizing selection?

Accepted Answer

It favors individuals with average phenotypes and acts against extreme phenotypes.

Question 2

A population of birds experiences a drought that causes only seeds with very hard shells to be available. Over several generations, the average beak size in the population increases. Which mode of natural selection is most likely responsible for this change?

Accepted Answer

Directional selection

Question 3

Which equation correctly represents the heritability ($$h^2) of a $$trait in terms of genetic and phenotypic variance?

Accepted Answer

$$h^2$$ = \frac{V_G}{V_P}$$

Question 4

In a study of Ural owls, egg size was found to be highly heritable and under stabilizing selection. What does this imply about the evolutionary process acting on egg size?

Accepted Answer

Egg size will remain relatively constant, with selection against very small and very large eggs.

Question 5

Which of the following scenarios best illustrates disruptive selection?

Accepted Answer

A population of fish where both very small and very large individuals have higher survival than medium-sized individuals.

Question 6

Which of the following is a likely consequence of genetic drift in a small, isolated island population?

Accepted Answer

Reduced genetic variation, making the population less able to adapt to environmental changes.

Question 7

Artificial selection in agriculture is best described as:

Accepted Answer

Selective breeding by humans to produce or maintain desirable traits in domesticated organisms.

Question 8

Which of the following best explains why pests can evolve resistance to pesticides used in agriculture?

Accepted Answer

Pests with natural resistance survive and reproduce, leading to an increase in resistant individuals over generations.

Question 9

Which of the following equations correctly incorporates both genetic and environmental variance in the calculation of heritability?

Accepted Answer

$$h^2$$ = \frac{V_G}{V_G + V_E}$$

Question 10

A population of finches on an island is observed to have two distinct beak sizes, with few individuals of intermediate size. Which evolutionary process is most likely responsible for this pattern?

Accepted Answer

Disruptive selection

Question 11

Which of the following statements about genetic drift is correct?

Accepted Answer

It can lead to random changes in allele frequencies, especially in small populations.

Question 12

Which of the following is an example of a founder effect?

Accepted Answer

A small group of individuals colonizes a new island, carrying only a subset of the genetic variation from the original population.

Question 13

Why is heritability important for evolution by natural selection?

Accepted Answer

Because only heritable traits can be passed on to the next generation and respond to selection.

Question 14

Which of the following best describes the bottleneck effect?

Accepted Answer

A large portion of a population is killed by a chance event, reducing genetic diversity.

Question 15

In the context of natural selection, what does 'fitness' refer to?

Accepted Answer

The ability of an individual to survive and reproduce in its environment.

Question 16

A population of soapberry bugs adapts to a new host plant with thicker fruit walls. Over time, the average beak length increases. This is an example of:

Accepted Answer

Directional selection

Question 17

Which of the following is NOT a requirement for evolution by natural selection?

Accepted Answer

All individuals must survive and reproduce equally

Question 18

If phenotypic variance ($$V_P) is 100$$, genetic variance ($$V_G) is 40$$, and environmental variance ($$V_E) is 60$$, what is the heritability ($$h^2) of $$the trait?

Accepted Answer

$$h^2$$ = \frac{40}{100} = 0.4$$

Question 19

Which of the following is a potential unintended evolutionary consequence of using chemicals in agriculture?

Accepted Answer

Evolution of resistance in plant and animal pests

Population Genetics and Natural Selection: Mechanisms and Applications

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