Q: In a population of 100 lizards, 60 are green (GG), 30 are blue-green (Gg), and 10 are blue (gg). What is the frequency of the g allele?

$$q = \frac{(2 \times 10) + 30}{2 \times 100} = \frac{20 + 30}{200} = \frac{50}{200} = 0.25$$

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

$$p = \frac{(2 \times 40) + 30}{2 \times 100} = \frac{80 + 30}{200} = \frac{110}{200} = 0.55$$

Q: If $$p = 0.8$$ and $$q = 0.2 in a $$population, what is the expected frequency of heterozygotes under Hardy-Weinberg equilibrium?

$$2pq = 2 \times 0.8 \times 0.2 = 0.32$$

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 of 100 lizards, 60 are green (GG), 30 are blue-green (Gg), and 10 are blue (gg). What is the frequency of the g allele?

Accepted Answer

$$q = \frac{(2 	imes 10) + 30}{2 	imes 100} = \frac{20 + 30}{200} = \frac{50}{200} = 0.25$$

Question 3

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

Accepted Answer

Genetic drift (bottleneck effect)

Question 4

A population of 100 people has two alleles for hair type: A (curly) and a (straight). 40 have curly hair (AA), 30 have wavy hair (Aa), and 30 have straight hair (aa). What is the frequency of the A allele?

Accepted Answer

$$p = \frac{(2 	imes 40) + 30}{2 	imes 100} = \frac{80 + 30}{200} = \frac{110}{200} = 0.55$$

Question 5

Which scenario best illustrates the founder effect?

Accepted Answer

A small group of birds migrates to a new island and establishes a population with different allele frequencies than the original population.

Question 6

If $$p = 0.8$$ and $$q = 0.2 in a $$population, what is the expected frequency of heterozygotes under Hardy-Weinberg equilibrium?

Accepted Answer

$$2pq = 2 	imes 0.8 	imes 0.2 = 0.32$$

Question 7

Which of the following best explains why perfect adaptations are rare in populations?

Accepted Answer

Evolution involves trade-offs, genetic variation, and changing environments, making perfect adaptation unlikely.

Question 8

A population of 1,000 individuals has a recessive genetic disorder expressed only in homozygous recessive individuals. If $$q^2 = 0.001$, what is the expected proportion of heterozygotes?

Accepted Answer

$$q = \sqrt{0.001} = 0.0316$$, $$p = 1 - 0.0316 = 0.9684$$, $$2pq = 2 	imes 0.9684 	imes 0.0316 = 0.0612$$

Question 9

Which type of selection maintains genetic diversity by favoring heterozygotes over both homozygotes?

Accepted Answer

Heterozygote advantage

Question 10

If a population is not in Hardy-Weinberg equilibrium, which of the following could be a possible cause?

Accepted Answer

Non-random mating

Question 11

A population of water snakes on an island receives migrants from the mainland every generation. What is the most likely effect of this gene flow?

Accepted Answer

It increases genetic variation and can alter allele frequencies in the island population.

Question 12

Which equation represents the Hardy-Weinberg principle for genotype frequencies?

Accepted Answer

$$p^2 + 2pq$$ + $$q^2 = 1$

Question 13

Which of the following is an example of frequency-dependent selection?

Accepted Answer

The fitness of a phenotype depends on how common it is in the population.

Question 14

Why are mutations considered a rare source of genetic variation in populations?

Accepted Answer

Mutations occur infrequently and most are neutral or deleterious.

Question 15

Which of the following statements about genetic drift is TRUE?

Accepted Answer

Genetic drift has a greater impact in small populations, causing unpredictable changes in allele frequencies.

Question 16

In a population, the frequency of the dominant allele is $$p = 0.6. $$What is the expected frequency of homozygous dominant individuals under Hardy-Weinberg equilibrium?

Accepted Answer

$$p^2$$ = $$0.6^2 = 0.36$

Question 17

Which of the following is a reason why evolution does not always lead to perfect adaptations?

Accepted Answer

Environments change, genetic variation is limited, and trade-offs exist.

Question 18

A population of finches experiences a drought, resulting in only large seeds being available. Over time, the average beak size increases. What type of selection is this?

Accepted Answer

Directional selection

Question 19

Which factor is most likely to maintain genetic variation in a population?

Accepted Answer

Balancing selection

Question 20

If a population is in Hardy-Weinberg equilibrium, what can be concluded about its allele frequencies?

Accepted Answer

Allele frequencies remain constant from generation to generation.

Population Genetics and Hardy-Weinberg Equilibrium: Study Notes for General Biology

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