Q: In a population of 500 wildflowers, there are 320 red (CRCR), 160 pink (CRCW), and 20 white (CWCW) individuals. What is the frequency of the CR allele?

$p = \frac{(320 \times 2) + 160}{1000} = 0.8$

Q: In a population in Hardy-Weinberg equilibrium, the frequency of allele $A$ is $0.7$ and allele $a$ is $0.3$. What is the expected frequency of heterozygotes ($Aa$)?

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

Question 1

Which of the following best describes evolution at its smallest scale?

Accepted Answer

A change in allele frequencies in a population over generations

Question 2

In a population of 500 wildflowers, there are 320 red (CRCR), 160 pink (CRCW), and 20 white (CWCW) individuals. What is the frequency of the CR allele?

Accepted Answer

$p = \frac{(320 	imes 2) + 160}{1000} = 0.8$

Question 3

Which mechanism of evolution is most likely responsible for a drastic reduction in genetic variation after a natural disaster wipes out most of a population?

Accepted Answer

Bottleneck effect

Question 4

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

Accepted Answer

Small population size

Question 5

A population of insects is exposed to an insecticide. Over time, the frequency of an allele for resistance increases. Which mechanism is most directly responsible for this change?

Accepted Answer

Natural selection

Question 6

Which of the following statements about genetic drift is TRUE?

Accepted Answer

It has a greater effect in small populations than in large populations

Question 7

If $p$ and $q$ represent the frequencies of two alleles at a locus, which equation represents the expected genotype frequencies under Hardy-Weinberg equilibrium?

Accepted Answer

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

Question 8

Which of the following is an example of gene flow?

Accepted Answer

Pollen from one population of flowers fertilizes plants in a different population

Question 9

A point mutation in a noncoding region of DNA is most likely to result in:

Accepted Answer

Neutral variation

Question 10

Which process is responsible for most genetic variation in sexually reproducing organisms?

Accepted Answer

Recombination of existing alleles during sexual reproduction

Question 11

In a population in Hardy-Weinberg equilibrium, the frequency of allele $A$ is $0.7$ and allele $a$ is $0.3$. What is the expected frequency of heterozygotes ($Aa$)?

Accepted Answer

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

Question 12

Which of the following scenarios best illustrates the founder effect?

Accepted Answer

A few individuals from a mainland population colonize a new island, resulting in different allele frequencies than the original population

Question 13

Which of the following is a consequence of gene flow between two populations?

Accepted Answer

It tends to reduce genetic differences between populations

Question 14

Why can harmful alleles sometimes increase in frequency in a population due to genetic drift?

Accepted Answer

Because genetic drift is a random process that can fix alleles regardless of their effect on fitness

Question 15

Which of the following is an example of phenotypic variation that is NOT heritable?

Accepted Answer

A plant's leaf color changes due to soil pH

Question 16

Which of the following would violate the assumption of random mating in a population?

Accepted Answer

Individuals preferentially mate with close relatives (inbreeding)

Question 17

A population of birds on an island has a high frequency of a beak shape allele that is rare on the mainland. Which mechanism most likely explains this difference?

Accepted Answer

Founder effect

Question 18

Which of the following best explains why natural selection can only act on heritable variation?

Accepted Answer

Only genetic differences can be passed to offspring

Question 19

Which of the following is most likely to result in a population being out of Hardy-Weinberg equilibrium at a particular gene locus?

Accepted Answer

Consistent differences in survival or reproduction among genotypes

Question 20

Which of the following is a real-world example of gene flow increasing a population's fitness?

Accepted Answer

The spread of insecticide resistance alleles into a mosquito population

The Evolution of Populations (Chapter 23, Campbell Biology)

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