Q: A population of beetles has two alleles for color: B (black) and b (brown). If the frequency of B is $$p = 0.7$$ and the frequency of b is $$q = 0.3$$, what is the expected frequency of heterozygotes ($$Bb) $$under Hardy-Weinberg equilibrium?

$$2pq = 2 \times 0.7 \times 0.3 = 0.42$$

Q: If the half-life of a radioactive isotope is 5,000 years, how much of a 100g sample will remain after 15,000 years?

$$100 \div 2^3$ = 12.5\text{g}$$

Question 1

Which of the following best describes the mechanism of natural selection as proposed by Darwin and Wallace?

Accepted Answer

Individuals with traits best suited to their environment are more likely to survive and reproduce, passing those traits to the next generation.

Question 2

Which of the following is NOT a requirement for Hardy-Weinberg equilibrium in a population?

Accepted Answer

Natural selection favoring certain alleles

Question 3

A population of beetles has two alleles for color: B (black) and b (brown). If the frequency of B is $$p = 0.7$$ and the frequency of b is $$q = 0.3$$, what is the expected frequency of heterozygotes ($$Bb) $$under Hardy-Weinberg equilibrium?

Accepted Answer

$$2pq = 2 	imes 0.7 	imes 0.3 = 0.42$$

Question 4

Which evolutionary force is most likely responsible for a sudden decrease in genetic diversity following a natural disaster?

Accepted Answer

Bottleneck effect

Question 5

Which of the following is an example of convergent evolution?

Accepted Answer

The wings of bats and birds, which evolved independently for flight

Question 6

Which pattern of natural selection favors individuals at both extremes of a trait distribution?

Accepted Answer

Disruptive selection

Question 7

Which of the following best explains why genetic variation is necessary for natural selection?

Accepted Answer

Without genetic variation, all individuals would be equally adapted, and selection could not favor any particular trait.

Question 8

Which of the following is a postzygotic reproductive barrier?

Accepted Answer

Hybrid sterility

Question 9

A scientist discovers two populations of frogs that live in the same pond but breed at different times of the year. What type of reproductive isolation is this?

Accepted Answer

Temporal isolation

Question 10

Which of the following statements about allopatric speciation is correct?

Accepted Answer

It occurs when populations are geographically separated, leading to the formation of new species.

Question 11

Which of the following best describes a clade in phylogenetic systematics?

Accepted Answer

A group consisting of an ancestor and all its descendants

Question 12

Which of the following is a shared derived character (synapomorphy) in mammals?

Accepted Answer

Hair

Question 13

Which hypothesis best explains the origin of eukaryotic cells from prokaryotic ancestors?

Accepted Answer

Endosymbiotic theory

Question 14

Which of the following events is most likely to result in adaptive radiation?

Accepted Answer

A group of organisms colonizes a new, unoccupied habitat with diverse resources.

Question 15

Which of the following best describes homology?

Accepted Answer

Similarity due to shared ancestry

Question 16

If the half-life of a radioactive isotope is 5,000 years, how much of a 100g sample will remain after 15,000 years?

Accepted Answer

$$100 \div 2^3$ = 12.5	ext{g}$$

Question 17

Which of the following is an example of a polyphyletic group?

Accepted Answer

A group that includes bats and birds but not their common ancestor

Question 18

Which evolutionary process is most likely to increase genetic differences between two populations?

Accepted Answer

Natural selection in different environments

Question 19

Which of the following best explains why the fossil record is incomplete?

Accepted Answer

Many organisms lack hard parts and are unlikely to fossilize.

Question 20

Which of the following is a correct application of the principle of parsimony in phylogenetic analysis?

Accepted Answer

Choosing the tree that requires the fewest evolutionary changes

Evolutionary Biology: Descent, Populations, Speciation, and Phylogeny

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