Q: A population of 100 people has 40 with curly hair (AA), 30 with wavy hair (Aa), and 30 with straight hair (aa). What is the frequency of the A allele?

$$f(A) = \frac{(2 \times 40) + 30}{2 \times 100} = 0.55$$

Question 1

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

Accepted Answer

Small population size

Question 2

In a population with two alleles, A and a, the frequency of allele A is $$p = 0.7. $$What is the frequency of allele a?

Accepted Answer

$$q = 0.3$$

Question 3

If $$p = 0.6$$ and $$q = 0.4 in a $$population, what is the expected frequency of heterozygotes under Hardy-Weinberg equilibrium?

Accepted Answer

$$2pq = 0.48$$

Question 4

A population of 100 people has 40 with curly hair (AA), 30 with wavy hair (Aa), and 30 with straight hair (aa). What is the frequency of the A allele?

Accepted Answer

$$f(A) = \frac{(2 	imes 40) + 30}{2 	imes 100} = 0.55$$

Question 5

Which evolutionary mechanism is most likely to reduce genetic variation in a small population after a bottleneck event?

Accepted Answer

Genetic drift

Question 6

Why do lethal or deleterious alleles persist in populations despite natural selection?

Accepted Answer

They can be hidden in heterozygotes due to diploidy

Question 7

Which mode of selection favors individuals at both extremes of a phenotypic range?

Accepted Answer

Disruptive selection

Question 8

A population of water snakes on an island has both banded and unbanded morphs. If gene flow from the mainland is reduced, what is the most likely outcome?

Accepted Answer

Decreased genetic variation and increased local adaptation

Question 9

If the frequency of a lethal recessive phenotype in a population is $$q^2 = 0.001$, what is the approximate frequency of heterozygotes?

Accepted Answer

$$2pq \approx 0.063$$

Question 10

Which of the following best describes the founder effect?

Accepted Answer

A small group colonizes a new area, resulting in different allele frequencies from the source population

Question 11

What is the significance of the null condition in Hardy-Weinberg equilibrium?

Accepted Answer

It provides a baseline to detect evolutionary change

Question 12

Which equation represents the sum of allele frequencies in a population with two alleles?

Accepted Answer

$$p + q = 1$$

Question 13

In a population at Hardy-Weinberg equilibrium, what is the expected frequency of homozygous dominant individuals if $$p = 0.8$$?

Accepted Answer

$$p^2 = 0.64$

Question 14

Which of the following is an example of heterozygote advantage?

Accepted Answer

Individuals with one sickle-cell allele and one normal allele are resistant to malaria and do not have sickle-cell disease

Question 15

Which evolutionary mechanism can introduce new alleles into a population, increasing genetic variation?

Accepted Answer

Gene flow

Question 16

Why can't natural selection produce perfect adaptations?

Accepted Answer

Environments are constantly changing and there are ecological trade-offs

Question 17

Which mode of selection would most likely result in a decrease in the variance of a trait, favoring intermediate phenotypes?

Accepted Answer

Stabilizing selection

Question 18

A population of 200 people is surveyed and 100 have curly hair, 50 have wavy hair, and 50 have straight hair. If the expected numbers under Hardy-Weinberg equilibrium are different, what does this indicate?

Accepted Answer

The population is evolving

Question 19

Frequency-dependent selection is best described as:

Accepted Answer

Selection where the fitness of a phenotype depends on its frequency relative to other phenotypes

Population Genetics and Evolution: Hardy-Weinberg Equilibrium and Mechanisms of Evolution (Ch. 23)

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