Question 1

Which of the following is an example of gene flow?
A) Pollen from a population A plant lands on the same plant (mating with itself).
B) Pollen from a population A plant lands on another population A plant.
C) Pollen from a population A plant lands on a population B plant.
D) Pollen from a population B plant lands on a population B plant.

Accepted Answer

Gene flow is the transfer of genetic material from one population to another. In option C, pollen from a population A plant lands on a population B plant, leading to the transfer of genetic material between the two populations. Options A and B do not involve gene flow because they do not involve a transfer of genetic material between populations. Option D involves pollen from a population B plant landing on another population B plant, which also does not involve gene flow between populations.

Question 2

If a given population has 30 RR individuals, 10 Rr individuals, and 10 rr individuals, what is the genotype frequency of Rr?
A) 0.10
B) 0.20
C) 0.30
D) 0.50

Accepted Answer

There are two ways to calculate the genotype frequency of Rr:

1) Add up all the Rr individuals and divide by the total population size:
Rr frequency = (10 Rr individuals) / (30 RR individuals + 10 Rr individuals + 10 rr individuals) = 0.20

2) Use the Hardy-Weinberg equation:
p^2 + 2pq + q^2 = 1, where p is the frequency of the R allele and q is the frequency of the r allele.

First, calculate the frequency of the R allele:
p = (2 x number of RR individuals + number of Rr individuals) / (2 x total population size)
p = (2 x 30 + 10) / (2 x 50) = 0.7

Next, calculate the frequency of the r allele:
q = 1 - p
q = 0.3

Finally, use the equation to find the frequency of Rr:
2pq = 2 x 0.7 x 0.3 = 0.42
Rr frequency = 0.42 / 2 = 0.21 (rounded to the nearest hundredth)

Since the answer choices are not very close to each other, it's easy to see that the correct answer is B: 0.20.

Question 3

New alleles arise by
A) nonrandom mating.
B) allele frequency.
C) genetic drift.
D) mutation.

Accepted Answer

New alleles arise through mutations, which are changes in the DNA sequence. Mutations can occur spontaneously or be induced by mutagens (chemical or physical agents).

Question 4

The human allele that causes six fingers per hand is dominant over the allele that produces five fingers per hand. Yet most humans have five fingers per hand. Why is this so?
A) A Punnett square shows this situation to be impossible.
B) The F2 generation never expresses the dominant trait.
C) The heterozygote expresses the recessive trait.
D) The six-finger allele exists at a low frequency in the human population.

Accepted Answer

The six-finger allele exists at a low frequency in the human population. Even though the six-finger allele is dominant, it exists at a low frequency in the human population. Therefore, the chances of two individuals carrying the six-finger allele coming together to produce offspring that express the trait is relatively low, leading to most humans having five fingers per hand.

Question 5

A population has a total of two alleles, G and g, for a given gene. Which one of the following sets of genotype frequencies is correctly expressed for that population?
A) GG = .25 Gg = .75 gg = .35
B) GG = .70 Gg = .25 gg = .30
C) GG = .75 Gg = .15 gg = .10
D) GG = .45 Gg = .15 gg = .75

Accepted Answer

A population can have a total of two alleles for a given gene, which are represented by letters, usually uppercase and lowercase. In this case, the two alleles are G and g.

The genotype frequencies represent the proportion of individuals in the population that have a particular combination of alleles.

In option A, the sum of the genotype frequencies is greater than 1, which is not possible.

In option B, the sum of the genotype frequencies is also greater than 1.

In option D, the frequency of the gg genotype is greater than 1, which is not possible.

Option C is the only one where the sum of the genotype frequencies is equal to 1, which is the total frequency of all possible genotypes. Therefore, it is the correct set of genotype frequencies for the given population.

Question 6

Which of the following processes does not lead to an increase in recombination?
A) fertilization
B) crossing over
C) independent assortment of chromosomes
D) DNA repair

Accepted Answer

DNA repair does not involve the exchange of genetic material between non-sister chromatids, which is the definition of recombination. Instead, it is the process of correcting mistakes or damage in the DNA molecule itself. The other choices (A, B, and C) involve mechanisms that can increase recombination. Fertilization is the union of gametes, each of which contains a unique combination of parental chromosomes. Crossing over is the exchange of genetic material between non-sister chromatids during meiosis. Independent assortment of chromosomes is the random sorting of homologous chromosome pairs during meiosis.

Question 7

In the figure below, the flying bird moves permanently into the population shown on land. 
As a result, the allele frequency of A changes from
A) 1 to 0.75.
B) 0 to 0.25.
C) 0 to 0.75.
D) 1 to 0.25.

Accepted Answer

The answer of In the figure below, the flying bird...

Question 8

Which of the following is correct?
A) Giraffes did not evolve from other organisms.
B) Giraffes stretch to obtain food and for this reason their necks become longer. This characteristic is passed on to the next generation.
C) A giraffe's offspring are more likely to have longer necks than it does.
D) A giraffe's offspring, on average, will have necks of the same length that it has.

Accepted Answer

Giraffe offspring inherit genetic traits from their parents, so on average, they will have necks of similar length to their parents, barring any significant evolutionary changes.

Question 9

Does sexual reproduction alone necessarily cause evolution?
A) Yes, sexual reproduction causes genetic drift.
B) Yes, sexual reproduction is the only source of new heritable mutations.
C) No, sexual reproduction creates variation, but evolution may or may not act on that variation.
D) No, sexual reproduction produces new combinations of alleles that are never subject to natural selection.

Accepted Answer

Sexual reproduction creates genetic variation, but whether or not this variation results in evolution depends on whether natural selection, genetic drift, or other factors act on the variation. Therefore, sexual reproduction alone does not necessarily cause evolution. Option A and D are incorrect because genetic drift is a random process that can occur in populations with or without sexual reproduction, and new combinations of alleles produced by sexual reproduction can certainly be subject to natural selection. Option B is incorrect because mutations can occur spontaneously, regardless of whether organisms reproduce sexually or asexually.

Question 10

In a population of 100,000 flies, 30,000 have the AA genotype, 20,000 carry the Aa genotype, and 50,000 have the aa genotype. What is the frequency of the A allele?
A) 1.00
B) 0.80
C) 0.40
D) 0.30

Accepted Answer

The answer of In a population of 100,000 flies, 30,000...

Question 11

Which of the following statements concerning evolution is false?
A) Natural selection requires variation in the population.
B) An individual that is better adapted than others in a population will always be more reproductively successful.
C) Genetic drift causes little evolutionary change in large populations.
D) Evolution involves a change of frequency of alleles in the gene pool.

Accepted Answer

An individual that is better adapted than others in a population may not always be more reproductively successful, as there are other factors, such as chance events and mate choice, that can affect an individual's reproductive success.

Question 12

Microevolution
A) does not alter the genotype frequencies of a population.
B) is caused by speciation.
C) occurs only in microorganisms.
D) is the smallest scale at which evolution occurs.

Accepted Answer

Microevolution refers to small-scale genetic changes within a population over time, such as changes in allele frequencies. It is the smallest scale at which evolution occurs, but it can lead to larger-scale changes over long periods of time. Speciation, the process by which new species arise, is a type of macroevolution, which involves larger-scale changes in the characteristics of species. Microevolution can occur in all organisms, not just microorganisms.

Question 13

The genetic variation in a population is increased by
A) recombination.
B) allele fixation.
C) natural selection.
D) genetic drift.

Accepted Answer

Recombination, the shuffling of genetic information during meiosis, creates new combinations of alleles that did not exist in the parental generation. This increases genetic variation within the population. Allele fixation, natural selection, and genetic drift can lead to a decrease in genetic variation.

Question 14

What is the total number of alleles for the T gene present in a population of 100 individuals?
A) 50
B) 100
C) 200
D) 400

Accepted Answer

Each individual has two alleles for a given gene (one from each parent), so the total number of alleles in the population can be found by multiplying the number of individuals by two. Therefore, 100 individuals x 2 alleles per individual = 200 alleles in total for the T gene in this population. Choice C is the only option that corresponds with this calculation.

Question 15

Which of the following factors is not likely to cause major changes in allele frequencies?
A) microevolution
B) gene flow
C) mutation
D) natural selection

Accepted Answer

The answer of Which of the following factors is not...

Question 16

While on a camping trip, you collect some white tadpoles from a pond and take them home. The tadpoles develop into white bullfrogs. When the frogs get too big, you release them into a local pond. The next year, several white bullfrogs are observed in the pond. This is an example of
A) genetic drift.
B) natural selection.
C) gene flow.
D) sexual selection.

Accepted Answer

The phenomenon described is an example of gene flow, which refers to the movement of genetic material (in this case, the white gene) from one population to another. By releasing the white bullfrogs into the local pond, they were able to mate and introduce the white gene to the original population of bullfrogs. This is not an example of genetic drift, natural selection, or sexual selection, as those processes do not involve the direct transfer of genetic material between populations.

Question 17

Gene flow can occur when individuals move from one population to another. It can also occur
A) as a result of genetic drift.
B) if gametes, rather than individuals, move among populations.
C) as a result of mutations in one population but not in another.
D) when individuals within a population interbreed.

Accepted Answer

Gene flow can occur when gametes, such as pollen or seeds, move between populations, allowing for the exchange of genetic material without the movement of individuals.

Question 18

If a given population has 30 RR individuals, 10 Rr individuals, and 10 rr individuals, what is the allele frequency of R?
A) 0.10
B) 0.30
C) 0.50
D) 0.70

Accepted Answer

The answer of If a given population has 30 RR...

Question 19

One factor that complicates the treatment of AIDS is the
A) low mutation rate of HIV.
B) high mutation rate of HIV.
C) random mating between viral particles.
D) non-random mating between viral particles.

Accepted Answer

The high mutation rate of HIV makes it difficult to design drugs that completely eliminate the virus, and it also allows the virus to develop drug resistance quickly.

Question 20

Gene flow between two populations
A) makes the genetic composition of the two populations more similar.
B) eliminates harmful alleles.
C) magnifies the effects of genetic drift.
D) creates genetic differences between the populations.

Accepted Answer

Gene flow is the movement of genes from one population to another. It increases the genetic variation within each population and decreases genetic differences between them. As a result, the genetic composition of the two populations becomes more similar over time.

Quiz 17: Evolution of Populations

Which of the following is an example of gene flow?

If a given population has 30 RR individuals, 10 Rr individuals, and 10 rr individuals, what is the genotype frequency of Rr?

New alleles arise by

The human allele that causes six fingers per hand is dominant over the allele that produces five fingers per hand. Yet most humans have five fingers per hand. Why is this so?

A population has a total of two alleles, G and g, for a given gene. Which one of the following sets of genotype frequencies is correctly expressed for that population?

Which of the following processes does not lead to an increase in recombination?

In the figure below, the flying bird moves permanently into the population shown on land. As a result, the allele frequency of A changes from

Which of the following is correct?

Does sexual reproduction alone necessarily cause evolution?

In a population of 100,000 flies, 30,000 have the AA genotype, 20,000 carry the Aa genotype, and 50,000 have the aa genotype. What is the frequency of the A allele?

Which of the following statements concerning evolution is false?

Microevolution

The genetic variation in a population is increased by

What is the total number of alleles for the T gene present in a population of 100 individuals?

Which of the following factors is not likely to cause major changes in allele frequencies?

While on a camping trip, you collect some white tadpoles from a pond and take them home. The tadpoles develop into white bullfrogs. When the frogs get too big, you release them into a local pond. The next year, several white bullfrogs are observed in the pond. This is an example of

Gene flow can occur when individuals move from one population to another. It can also occur

If a given population has 30 RR individuals, 10 Rr individuals, and 10 rr individuals, what is the allele frequency of R?

One factor that complicates the treatment of AIDS is the

Gene flow between two populations