Question 1

Inbreeding

Accepted Answer

Inbreeding increases homozygosity in populations by increasing the chances of offspring inheriting the same alleles from both parents.

Question 2

Over the same landscape, populations may differ in degree of subdivision depending on their movement. Which of the following is/are true?

Accepted Answer

Species that move widely across a landscape tend to have minimal genetic divergence because their movement facilitates gene flow, reducing genetic differences between populations.

Question 3

In the Hardy-Weinberg equation, what does 2pq refer to?

Accepted Answer

2pq represents the frequency of heterozygotes in a population according to the Hardy-Weinberg principle, which describes the genetic equilibrium within a population.

Question 4

A mosquito that has the genotype Ester¹Ester¹ is considered ____ and is ____ at the esterase locus.

Accepted Answer

The mosquito is homozygous because it has two identical alleles for each gene mentioned (Ester¹ repeated twice), and it is diploid because it has two sets of chromosomes, one from each parent.

Question 5

The probability of an allele being lost during a genetic bottleneck depends on

Accepted Answer

The answer of The probability of an allele being lost...

Question 6

Many plant species are hermaphroditic and run the risk of self-mating. Some species carry self-incompatibility alleles that can prevent this from occurring. If a pollen grain with self-incompatibility allele S₁ lands on a stigma that also carries the S₁ allele, the pollen will not germinate and fertilization does not occur. Thus, this mechanism not only prevents selfing, but also has the unfortunate effect of preventing mating with any other plant that carries the same allele. However, if the pollen lands on a stigma of a plant with a different allele, fertilization occurs. Imagine a population of plants in which the allele frequency of S₁ = 0.9 and the allele frequency of S₂ = 0.1. All other things being equal, individuals with the ____ allele will have higher fitness on average. This is an example of ______.

Accepted Answer

Individuals with the S₂ allele will have higher fitness because they can mate with the majority of the population that carries the S₁ allele. This is an example of negative frequency-dependent selection, where the fitness of a phenotype increases as it becomes less common.

Question 7

Which of the following is not an assumption of the Hardy-Weinberg theorem?

Accepted Answer

The Hardy-Weinberg theorem assumes no gene flow, which means no immigration or emigration. Choice C incorrectly suggests that emigration without immigration is compatible with the theorem's assumptions.

Question 8

If p = 0.8, what is the frequency of heterozygotes in a population, assuming Hardy-Weinberg equilibrium?

Accepted Answer

In a population at Hardy-Weinberg equilibrium, the frequency of heterozygotes can be calculated using the formula 2pq, where p is the frequency of one allele, and q is the frequency of the other allele. Given p = 0.8, q = 1 - p = 0.2. Therefore, the frequency of heterozygotes = 2(0.8)(0.2) = 0.32.

Question 9

How is a null hypothesis useful in studying how allele frequencies change?

Accepted Answer

A null hypothesis is useful because it serves as a baseline for change (A) and explains what happens when there is no change (B), allowing researchers to compare observed data against what would be expected if no evolutionary forces were acting on the population.

Question 10

Assuming that a deleterious allele is maintained in a population by mutation-selection balance, which scenario below describes the case where you would expect the equilibrium frequency of the allele to be highest?

Accepted Answer

In a mutation-selection balance, the equilibrium frequency of a deleterious allele is determined by the rate at which new mutations introduce the allele into the population and the rate at which selection removes it. A high mutation rate increases the frequency of the allele, and if the allele is only slightly deleterious, selection against it is weaker, allowing it to reach a higher equilibrium frequency.

Question 11

Which of the following is not true about a fixed genetic locus?

Accepted Answer

All statements A, B, and C are true about a fixed genetic locus, so none of them is not true.

Question 12

In comparison with genetic drift, evolution by natural selection is

Accepted Answer

Evolution by natural selection is nonrandom and adaptive because it involves the differential survival and reproduction of individuals due to differences in phenotype, leading to adaptations to the environment.

Question 13

Tasmanian devils once inhabited most of present-day Australia, but only an isolated population on the island of Tasmania has survived to the present day. Which of the following processes has likely affected Tasmanian devils as a result of this history?

Accepted Answer

A genetic bottleneck occurs when a population's size is significantly reduced for at least one generation, leading to a loss of genetic diversity. This is likely what happened to Tasmanian devils when their population became restricted to Tasmania, reducing their genetic diversity compared to when they inhabited a larger area.

Question 14

Which of the following is an example of the founder effect?

Accepted Answer

The founder effect occurs when a new population is established by a small number of individuals, which is exemplified by a plant seed starting a new population after being transported by a bird.

Question 15

Alleles are

Accepted Answer

Alleles are indeed found at genetic loci, which are specific positions on chromosomes. Not all alleles are strictly dominant or recessive; some exhibit incomplete dominance, codominance, or other patterns of inheritance. Also, alleles are alternative forms of a gene, not a phenotype, which is the observable characteristic.

Question 16

The graph below shows the change in allele frequency for a beneficial allele over time (the x axis shows generations). Based on the shape of the curve, this allele is most likely

Accepted Answer

The answer of The graph below shows the change in...

Question 17

Why was Charles II of Spain, of the Hapsburg dynasty, called el hechizado, the "hexed"?

Accepted Answer

Charles II of Spain was called "el hechizado" because many believed his numerous health issues were due to sorcery or a curse.

Question 18

A genetic bottleneck occurs when

Accepted Answer

The answer of A genetic bottleneck occurs when
...

Question 19

Although the Ester¹ allele confers a selective advantage to mosquitoes exposed to DDT on the coast of France, carriers of Ester¹ in inland populations are more likely to be caught by spiders and other predators. This is an example of

Accepted Answer

This is an example of antagonistic pleiotropy, where a single gene has multiple effects (pleiotropy) that are beneficial in one context (resistance to DDT) but detrimental in another (increased predation risk).

Question 20

In a population of butterflies that has two alleles at a locus for spots, no spots (N) and spots (S), there are 20 individuals with the NN genotype, 40 with the NS genotype, and 40 with the SS genotype. What is the frequency of N in the population?

Accepted Answer

The frequency of N in the population can be calculated by taking the total number of N alleles and dividing it by the total number of alleles. There are 20 NN individuals (2N each), 40 NS individuals (1N each), and 40 SS individuals (0N). So, the total number of N alleles is (20*2) + (40*1) = 40 + 40 = 80. The total number of alleles is 2*(20+40+40) = 200. Therefore, the frequency of N is 80/200 = 0.4.

Quiz 6: The Ways of Change: Drift and Selection

Inbreeding

Over the same landscape, populations may differ in degree of subdivision depending on their movement. Which of the following is/are true?

In the Hardy-Weinberg equation, what does 2pq refer to?

A mosquito that has the genotype Ester¹Ester¹ is considered and is at the esterase locus.

The probability of an allele being lost during a genetic bottleneck depends on

Which of the following is not an assumption of the Hardy-Weinberg theorem?

If p = 0.8, what is the frequency of heterozygotes in a population, assuming Hardy-Weinberg equilibrium?

How is a null hypothesis useful in studying how allele frequencies change?

Assuming that a deleterious allele is maintained in a population by mutation-selection balance, which scenario below describes the case where you would expect the equilibrium frequency of the allele to be highest?

Which of the following is not true about a fixed genetic locus?

In comparison with genetic drift, evolution by natural selection is

Tasmanian devils once inhabited most of present-day Australia, but only an isolated population on the island of Tasmania has survived to the present day. Which of the following processes has likely affected Tasmanian devils as a result of this history?

Which of the following is an example of the founder effect?

Alleles are

The graph below shows the change in allele frequency for a beneficial allele over time (the x axis shows generations) . Based on the shape of the curve, this allele is most likely

Why was Charles II of Spain, of the Hapsburg dynasty, called el hechizado, the "hexed"?

A genetic bottleneck occurs when

Although the Ester¹ allele confers a selective advantage to mosquitoes exposed to DDT on the coast of France, carriers of Ester¹ in inland populations are more likely to be caught by spiders and other predators. This is an example of

In a population of butterflies that has two alleles at a locus for spots, no spots (N) and spots (S) , there are 20 individuals with the NN genotype, 40 with the NS genotype, and 40 with the SS genotype. What is the frequency of N in the population?

Quiz 6: The Ways of Change: Drift and Selection

Inbreeding

Over the same landscape, populations may differ in degree of subdivision depending on their movement. Which of the following is/are true?

In the Hardy-Weinberg equation, what does 2pq refer to?

A mosquito that has the genotype Ester1Ester1 is considered ____ and is ____ at the esterase locus.

The probability of an allele being lost during a genetic bottleneck depends on

Which of the following is not an assumption of the Hardy-Weinberg theorem?

If p = 0.8, what is the frequency of heterozygotes in a population, assuming Hardy-Weinberg equilibrium?

How is a null hypothesis useful in studying how allele frequencies change?

Assuming that a deleterious allele is maintained in a population by mutation-selection balance, which scenario below describes the case where you would expect the equilibrium frequency of the allele to be highest?

Which of the following is not true about a fixed genetic locus?

In comparison with genetic drift, evolution by natural selection is

Tasmanian devils once inhabited most of present-day Australia, but only an isolated population on the island of Tasmania has survived to the present day. Which of the following processes has likely affected Tasmanian devils as a result of this history?

Which of the following is an example of the founder effect?

Alleles are

The graph below shows the change in allele frequency for a beneficial allele over time (the x axis shows generations) . Based on the shape of the curve, this allele is most likely

Why was Charles II of Spain, of the Hapsburg dynasty, called el hechizado, the "hexed"?

A genetic bottleneck occurs when

Although the Ester1 allele confers a selective advantage to mosquitoes exposed to DDT on the coast of France, carriers of Ester1 in inland populations are more likely to be caught by spiders and other predators. This is an example of

In a population of butterflies that has two alleles at a locus for spots, no spots (N) and spots (S) , there are 20 individuals with the NN genotype, 40 with the NS genotype, and 40 with the SS genotype. What is the frequency of N in the population?

A mosquito that has the genotype Ester¹Ester¹ is considered and is at the esterase locus.

Although the Ester¹ allele confers a selective advantage to mosquitoes exposed to DDT on the coast of France, carriers of Ester¹ in inland populations are more likely to be caught by spiders and other predators. This is an example of