Question 1

According to the biological species concept, which of the following scenarios best illustrates the definition of a species?

Accepted Answer

A population of frogs that can mate with each other and produce fertile offspring, but cannot produce fertile offspring with nearby frog populations.

Question 2

Two populations of crickets live in the same field, but one population mates at night and the other during the day. What type of reproductive isolation is this?

Accepted Answer

Temporal isolation

Question 3

Which of the following best describes the outcome of artificial selection in domesticated animals such as dogs?

Accepted Answer

It can lead to exaggerated traits, such as extremely short legs or flat faces.

Question 4

A population of weeds is sprayed with herbicide. Most die, but a few survive due to a genetic mutation. Over several generations, the population is mostly herbicide-resistant. This is an example of:

Accepted Answer

Natural selection

Question 5

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

Accepted Answer

Mating is non-random

Question 6

Which statement correctly distinguishes microevolution from macroevolution?

Accepted Answer

Microevolution is a change in allele frequencies within a population, while macroevolution leads to the formation of new species.

Question 7

Which of the following is an example of convergent evolution?

Accepted Answer

The development of wings in both bats and birds, even though they are not closely related.

Question 8

A volcanic eruption drastically reduces the size of a population of lizards, leaving only a few survivors. The new population has much less genetic diversity. This is an example of:

Accepted Answer

Bottleneck effect

Question 9

The allele for polydactyly (extra fingers or toes) is dominant, yet it is not the most common trait in human populations. Why?

Accepted Answer

Dominant alleles are not necessarily the most prevalent in a population.

Question 10

Which of the following is NOT a possible outcome for a hybrid zone over time?

Accepted Answer

Hybrid breakdown, where hybrids become stronger and replace both parent species.

Question 11

If the frequency of allele $$A in a $$population is $$0.3$$, what is the frequency of the other allele $$a$$, assuming only two alleles exist?

Accepted Answer

$$0.7$$

Question 12

Which of the following best describes how genetic drift differs from natural selection?

Accepted Answer

Genetic drift is based on chance, while natural selection is driven by fitness advantages.

Question 13

When constructing phylogenetic trees, what does the principle of parsimony suggest?

Accepted Answer

The tree with the fewest evolutionary changes is most likely correct.

Question 14

Why are molecular homologies often considered more reliable than anatomical homologies in constructing phylogenies?

Accepted Answer

DNA changes occur randomly and provide more measurable data.

Question 15

Which of the following is an example of allopatric speciation?

Accepted Answer

A population of squirrels becoming isolated on two sides of the Grand Canyon and evolving into two species.

Question 16

What is the role of hybrid zones in speciation?

Accepted Answer

They allow limited gene flow and can lead to reinforcement, fusion, or stability of species.

Question 17

Which of the following correctly defines 'descent with modification'?

Accepted Answer

Species evolve over time due to genetic changes and environmental pressures.

Question 18

In a phylogenetic tree, what does a branch point represent?

Accepted Answer

The point where two species share a common ancestor.

Question 19

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

Accepted Answer

Non-random mating

Question 20

In a population, 36% of individuals are homozygous recessive ($$aa). $$Using the Hardy-Weinberg equation, what is the frequency of the dominant allele ($$A$$)?

Recall: $$q^2 = 0.36$, q$$ = \sqrt{0.36}$$, p + q = 1$.

Accepted Answer

$$0.6$$

Question 21

In a population of 200 individuals, 98 express the recessive phenotype. Assuming Hardy-Weinberg equilibrium, what percent of the population would you predict to be heterozygotes ($$Aa$$)?

Given: $$q^2$$ = \frac{98}{200} = 0.49$$, q = 0.7$, p = 0.3$, 2pq = 2$$ 	imes 0.3 	imes 0.7$$.

Accepted Answer

42%

Practice Guidance for BIOL 102 Exam 2 – Evolution, Population Genetics, and Speciation

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