Question 1

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

Accepted Answer

A population of beetles splits into two groups that can no longer interbreed and produce fertile offspring due to a mountain range forming between them.

Question 2

Two frog species live in the same pond but one breeds in early spring and the other in late summer. What type of reproductive isolation is this, and why is it important for speciation?

Accepted Answer

Temporal isolation; it prevents gene flow by separating breeding times.

Question 3

Which of the following best explains why artificial selection can produce dog breeds with exaggerated traits, such as extremely short legs or flat faces?

Accepted Answer

Humans select for specific traits, sometimes leading to extreme phenotypes not favored in nature.

Question 4

A population of bacteria is exposed to an antibiotic. Most die, but a few survive due to a genetic mutation. Over several generations, nearly all bacteria are resistant. Which evolutionary mechanism is primarily responsible for this change?

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 scenario best illustrates convergent evolution?

Accepted Answer

The independent evolution of wings in bats and birds, allowing both to fly despite not being closely related.

Question 7

A flood drastically reduces a population of deer, leaving only a few survivors. The genetic diversity of the population is much lower than before. This is an example of:

Accepted Answer

Bottleneck effect

Question 8

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

Accepted Answer

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

Question 9

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 10

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

Accepted Answer

$$0.7$$

Question 11

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 12

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 13

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 14

Which of the following is an example of allopatric speciation?

Accepted Answer

A population of squirrels becomes isolated on two sides of the Grand Canyon and evolves into two species.

Question 15

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 16

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

Accepted Answer

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

Question 17

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

Accepted Answer

The point where two species share a common ancestor.

Question 18

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

Accepted Answer

Non-random mating

Question 19

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

$$p = 0.4$$

Question 20

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$$, q = 0.7$, p = 0.3$, 2pq$$ = ?$$

Accepted Answer

$$2pq = 2 	imes 0.3 	imes 0.7 = 0.42 or 42$$%

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

Study Guide - Practice Questions

Study Guide - Flashcards