Q: In a population, allele A has a frequency of $p = 0.7$ and allele a has a frequency of $q = 0.3$. What is the expected frequency of heterozygotes ($2pq$) under Hardy-Weinberg equilibrium?

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

Question 1

Which of the following best describes microevolution?

Accepted Answer

A change in allele frequency over generations within a population.

Question 2

According to the Hardy-Weinberg equation $p^2 + 2pq + q^2 = 1$, what does $2pq$ represent?

Accepted Answer

The expected frequency of heterozygotes in the population.

Question 3

Which mechanism of evolution is most likely responsible for a sudden change in allele frequencies due to a natural disaster that drastically reduces population size?

Accepted Answer

Genetic drift (bottleneck effect)

Question 4

A population of birds migrates to a neighboring island and interbreeds with the local population. Which evolutionary mechanism is primarily at work?

Accepted Answer

Gene flow

Question 5

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

Accepted Answer

Non-random mating

Question 6

In a population, allele A has a frequency of $p = 0.7$ and allele a has a frequency of $q = 0.3$. What is the expected frequency of heterozygotes ($2pq$) under Hardy-Weinberg equilibrium?

Accepted Answer

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

Question 7

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

Accepted Answer

Disruptive selection

Question 8

A population of beetles shows a shift in color from green to brown over several generations due to predation. Which type of selection is most likely occurring?

Accepted Answer

Directional selection

Question 9

Which of the following increases genetic variation in a population during sexual reproduction?

Accepted Answer

Independent assortment of chromosomes

Question 10

If a population is not evolving, what should be true about the observed and expected allele frequencies?

Accepted Answer

They should be the same.

Question 11

Which scenario best illustrates the founder effect?

Accepted Answer

A small group of individuals colonizes a new area, resulting in a population with different allele frequencies than the original population.

Question 12

Which of the following is an example of sexual selection?

Accepted Answer

Peacocks evolving elaborate tail feathers to attract mates.

Question 13

Which process can lead to a fixed allele in a population?

Accepted Answer

When an allele no longer changes its frequency and is the only allele present for that gene.

Question 14

Which of the following is a source of genetic variation in populations?

Accepted Answer

Mutations

Question 15

A population of fish is isolated in a small pond after a flood. Over time, the allele frequencies in this population differ significantly from the original population. What is the most likely explanation?

Accepted Answer

Founder effect

Question 16

Which type of selection is most likely to reduce genetic variation by favoring intermediate phenotypes?

Accepted Answer

Stabilizing selection

Question 17

Which of the following statements about natural selection is TRUE?

Accepted Answer

Natural selection does not always mean 'the strongest survive'; sometimes traits like mate choice are favored.

Question 18

If $p = 0.4$ and $q = 0.6$ in a population, what is the expected frequency of homozygotes for allele 2 ($q^2$) under Hardy-Weinberg equilibrium?

Accepted Answer

$q^2 = 0.6^2 = 0.36$

Question 19

Which of the following is NOT a mechanism that can change allele frequencies in a population?

Accepted Answer

Mitosis in somatic cells

Question 20

A population of rabbits is exposed to a new predator. Over time, only the fastest rabbits survive and reproduce. What type of selection is this?

Accepted Answer

Directional selection

Population Genetics, Microevolution, and Natural Selection

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