Q: In a population with two alleles, $$B_1$$ and $$B_2$$, where $$p = 0.8$$ for $$B_1$$, what is the expected frequency of the $$B_1B_2$$ genotype under Hardy-Weinberg equilibrium?

$$2pq = 2 \times 0.8 \times 0.2 = 0.32$$

Question 1

Which statement best distinguishes a scientific fact from a scientific theory, according to Stephen J. Gould?

Accepted Answer

Facts are the world's data, while theories are structures of ideas that explain and interpret facts.

Question 2

Which of the following best describes the modern genetic definition of evolution?

Accepted Answer

The change in allele frequencies within a population over time.

Question 3

Which of the following is NOT an assumption of Hardy-Weinberg equilibrium?

Accepted Answer

Non-random mating

Question 4

A population of 1000 diploid individuals has a newly arisen neutral mutation present in one copy. What is the probability that this mutation will eventually become fixed in the population?

Accepted Answer

$$\frac{1}{2000}$$

Question 5

Which of the following best describes genetic drift?

Accepted Answer

A process where allele frequencies change due to random chance events.

Question 6

In a population at Hardy-Weinberg equilibrium with two alleles, $$A$$ and $$a$$, where $$p = 0.7$$ and $$q = 0.3$$, what is the expected frequency of heterozygotes?

Accepted Answer

$$2pq$$

Question 7

Which of the following scenarios best illustrates genotype-by-environment interaction?

Accepted Answer

One genotype produces different phenotypes depending on the environment.

Question 8

If the frequency of homozygotes in a population is 0.64, what is the genetic diversity ($$H) of $$the population?

Accepted Answer

$$H = 1 - 0.64 = 0.36$$

Question 9

Which of the following is a consequence of a population bottleneck?

Accepted Answer

Loss of polymorphism and decrease in genetic diversity.

Question 10

Which statement about the Neutral Theory of Molecular Evolution is correct?

Accepted Answer

Most mutations are neutral with respect to fitness and their fate is determined by genetic drift.

Question 11

In a population with two alleles, $$B_1$$ and $$B_2$$, where $$p = 0.8$$ for $$B_1$$, what is the expected frequency of the $$B_1B_2$$ genotype under Hardy-Weinberg equilibrium?

Accepted Answer

$$2pq = 2 	imes 0.8 	imes 0.2 = 0.32$$

Question 12

Which of the following best explains why genetic population size ($$N_e) is $$often less than census size ($$N$$)?

Accepted Answer

Because non-breeders and fluctuations in population size reduce the number of individuals contributing genes.

Question 13

Which of the following is NOT a source of genetic variation among individuals?

Accepted Answer

Random mating

Question 14

If $$F_{ST} = 0$$, what does this indicate about the genetic variation between subpopulations?

Accepted Answer

There is no genetic differentiation; all subpopulations are perfectly mixed.

Question 15

Which of the following mutations is most likely to contribute to polymorphism in a population?

Accepted Answer

A neutral mutation

Question 16

A population of birds on an island is studied for natural selection. Which factor would most likely violate Hardy-Weinberg equilibrium?

Accepted Answer

A drought causes only birds with large beaks to survive and reproduce.

Question 17

If the average heterozygosity in a metapopulation ($$H_T) is 0.5 $$and in a subpopulation ($$H_S) is 0.3$$, what is $$F_{ST}$$?

Accepted Answer

$$F_{ST} = \frac{H_T - H_S}{H_T} = \frac{0.5 - 0.3}{0.5} = 0.4$$

Question 18

Which of the following best describes phenotypic plasticity?

Accepted Answer

The ability of an organism to change its phenotype in response to changes in the environment.

Question 19

Which of the following is a direct result of independent assortment during meiosis?

Accepted Answer

Genes for different traits are inherited independently of one another.

Question 20

If the neutral mutation rate per site per generation ($$u) is$$ $$1 	imes 10$$^{-8}$$ and the number of base pair differences between two sequences is 20, what is the estimated divergence time in generations?

Accepted Answer

$$\frac{20}{2 	imes 1 	imes 10$$^{-8}$$} = 1 	imes 10^9$

Genetics and Evolution: Key Concepts and Mechanisms

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