Question 1

Frequency-dependent selection acts to decrease the frequency of which phenotype in a population?
A) The least common phenotype
B) The most common phenotype
C) The most conspicuous phenotype
D) The most camouflaged phenotype
E) The phenotype at an extreme of the normal distribution

Accepted Answer

Frequency-dependent selection often decreases the frequency of the most common phenotype because it can become a target for predators or pathogens, giving an advantage to less common phenotypes.

Question 2

Which is an example of nonrandom mating?
A) Selecting a mate by their genotype
B) Selecting a mate by their phenotype
C) Selecting a mate by their species richness
D) Selecting a mate by their family relationship
E) Selecting a mate by their success of defeating another

Accepted Answer

The answer of Which is an example of nonrandom mating?
A)...

Question 3

The common yarrow grows to different heights in response to different climates and different elevations. This is a classic example of:
A) mutation.
B) genetic drift.
C) natural selection.
D) neutral variation.
E) geographic variation.

Accepted Answer

Geographic variation refers to differences in the genetic composition or phenotypic traits of populations that are geographically separated, often due to different environmental pressures such as climate and elevation.

Question 4

Which best describes the effect of positive assortative mating in a population?
A) It causes natural selection.
B) It increases homozygosity.
C) It changes allele frequencies.
D) It stabilizes genotype frequencies.
E) It produces more mutations each generation.

Accepted Answer

Positive assortative mating occurs when individuals with similar phenotypes mate more frequently. This can increase the frequency of homozygous individuals in a population, as individuals with similar genotypes are more likely to mate and pass on similar alleles. This can also lead to an increase in the frequency of recessive traits and genetic disorders.

Question 5

Due to a rapid change in the environment, a population of ants was reduced from one million to one thousand. What type of genetic drift will occur in the gene pool of this population when it expands again?
A) gene flow
B) migration
C) natural selection
D) the founder effect
E) a genetic bottleneck

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.

Question 6

Seriously abnormal phenotypes or harmful mutations are acted against or reduced to low frequencies by which mechanism?
A) gene flow
B) genetic drift
C) natural selection
D) disruptive selection
E) beneficial mutations

Accepted Answer

Natural selection acts against harmful mutations by reducing their frequency in the population, as individuals with such mutations are less likely to survive and reproduce.

Question 7

Variation that does not alter the ability of an individual to survive and reproduce is therefore considered:
A) neutral
B) genetic
C) geographic
D) heterozygous
E) frequency-dependent

Accepted Answer

Variation that has no effect on the survival or reproductive success of an individual is considered neutral. This means that the variation does not provide an advantage or disadvantage in a specific environment, and therefore does not affect an individual's ability to survive and reproduce.

Question 8

In some populations, we can expect that inbred individuals will have ____ in the population than those not inbred.
A) more random mating
B) lower levels of surviving offspring
C) more changes in allele frequencies
D) more heterozygosity
E) fewer opportunities to mate

Accepted Answer

Inbred individuals often have lower levels of surviving offspring due to inbreeding depression, which can result in a higher expression of deleterious recessive alleles.

Question 9

Which region displays an example of the founder effect amongst its population?
A) China
B) Iceland
C) Central Africa
D) the United States
E) the United Kingdom

Accepted Answer

Iceland's population is an example of the founder effect due to its small initial population of Norse settlers, leading to limited genetic variation.

Question 10

With respect to the alleles for sickle cell anemia, which genotype(s) is (are) at a disadvantage to persons residing in tropical areas of Africa?
A) heterozygous
B) homozygous dominant
C) homozygous recessive
D) both heterozygous and homozygous dominant
E) both homozygous dominant and homozygous recessive

Accepted Answer

The answer of With respect to the alleles for sickle...

Question 11

Which of the following can produce a population of individuals with a relatively high frequency of a harmful or rare allele?
A) mutation
B) natural selection
C) the founder effect
D) artificial selection
E) migration between large populations

Accepted Answer

The founder effect occurs when a small group of individuals becomes isolated from a larger population, leading to a new population that may have a higher frequency of certain alleles, including harmful or rare ones, due to the limited genetic diversity of the founders.

Question 12

When mutations are not passed on from one generation to the next, then a mutation can:
A) arise in somatic cells.
B) result from genetic drift.
C) arise from the founder effect.
D) be balanced by polymorphism.
E) result from disruptive selection.

Accepted Answer

Mutations that are not passed on from one generation to the next can arise in somatic cells. Somatic mutations occur spontaneously during DNA replication and repair, or they can be induced by environmental factors such as radiation or chemicals. However, these mutations are not transmitted to offspring because they do not affect the germline cells.

Question 13

What is the only source of all new alleles?
A) mutation
B) gene flow
C) genetic drift
D) natural selection
E) genetic polymorphism

Accepted Answer

Mutations are the original source of all new alleles, as they introduce changes in the DNA sequence that can lead to new genetic variations.

Question 14

If individuals in the same town continue to only mate with other individuals from the same town, one would expect to see an increase in ____ within the population.
A) genetic drift
B) migration
C) heterozygosity
D) homozygosity
E) assortative mating

Accepted Answer

Continued mating within a closed population leads to increased homozygosity due to limited genetic variation and potential inbreeding.

Question 15

The movement of 25-year-old fertile individuals between Mexico and Canada will eventually contribute to:
A) mutation.
B) gene flow.
C) genetic drift.
D) natural selection.
E) directional selection.

Accepted Answer

The movement of individuals between Mexico and Canada will lead to gene flow, which is the transfer of genetic variation from one population to another. This can have a significant impact on the genetic diversity and evolution of both populations. The other options (mutation, genetic drift, natural selection, and directional selection) may also be influenced by gene flow, but are not directly caused by the movement of individuals between Mexico and Canada.

Question 16

Which mechanism results in changes in allele frequencies in a population from one generation to another?
A) gene flow
B) mutation
C) genetic drift
D) natural selection
E) disruptive selection

Accepted Answer

The answer of Which mechanism results in changes in allele...

Question 17

The migration of breeding individuals between populations causes a corresponding movement of alleles, which is referred to as:
A) mutation.
B) gene flow.
C) genetic drift.
D) natural selection.
E) directional selection.

Accepted Answer

The movement of alleles between populations through the migration of breeding individuals is referred to as gene flow. Mutations are the source of new alleles, genetic drift is the random fluctuation of allele frequencies in a population, natural selection is the differential survival and reproduction of individuals with certain traits, and directional selection is a type of natural selection that favors individuals with extreme traits.

Question 18

A population in which the allele and genotype frequencies do not change over time is said to be in:
A) genetic stasis.
B) allele balance.
C) genetic equilibrium.
D) population stability.
E) phenotype equilibrium.

Accepted Answer

A population that does not experience changes in their allele and genotype frequencies is in genetic equilibrium. This occurs when the population is not evolving, and the forces of genetic drift, mutation, migration, and natural selection are balanced. The Hardy-Weinberg principle is a widely used model to test for genetic equilibrium in populations.

Question 19

Evolution that involves changes in allele frequencies over just a few successive generations is referred to as:
A) natural selection.
B) microevolution.
C) macroevolution.
D) stabilizing selection.
E) directional selection.

Accepted Answer

Microevolution refers to the small-scale changes in allele frequencies that occur within a population over a relatively short period of time, often just a few generations. This can be caused by a variety of factors such as mutation, gene flow, genetic drift, and natural selection.

Question 20

A population of people who have lived in the middle of the jungle for thousands of years without coming in contact with other individuals would show evidence of:
A) genetic stasis.
B) polymorphism.
C) random mating.
D) genetic equilibrium.
E) increasing non-harmful alleles.

Accepted Answer

The answer of A population of people who have lived...

Quiz 19: Evolutionary Change in Populations

Frequency-dependent selection acts to decrease the frequency of which phenotype in a population?

Which is an example of nonrandom mating?

The common yarrow grows to different heights in response to different climates and different elevations. This is a classic example of:

Which best describes the effect of positive assortative mating in a population?

Due to a rapid change in the environment, a population of ants was reduced from one million to one thousand. What type of genetic drift will occur in the gene pool of this population when it expands again?

Seriously abnormal phenotypes or harmful mutations are acted against or reduced to low frequencies by which mechanism?

Variation that does not alter the ability of an individual to survive and reproduce is therefore considered:

In some populations, we can expect that inbred individuals will have ____ in the population than those not inbred.

Which region displays an example of the founder effect amongst its population?

With respect to the alleles for sickle cell anemia, which genotype(s) is (are) at a disadvantage to persons residing in tropical areas of Africa?

Which of the following can produce a population of individuals with a relatively high frequency of a harmful or rare allele?

When mutations are not passed on from one generation to the next, then a mutation can:

What is the only source of all new alleles?

If individuals in the same town continue to only mate with other individuals from the same town, one would expect to see an increase in ____ within the population.

The movement of 25-year-old fertile individuals between Mexico and Canada will eventually contribute to:

Which mechanism results in changes in allele frequencies in a population from one generation to another?

The migration of breeding individuals between populations causes a corresponding movement of alleles, which is referred to as:

A population in which the allele and genotype frequencies do not change over time is said to be in:

Evolution that involves changes in allele frequencies over just a few successive generations is referred to as:

A population of people who have lived in the middle of the jungle for thousands of years without coming in contact with other individuals would show evidence of: