Deck 21: Evolution: How Genotypes and Phenotypes Change Over Time

Question 1

What is the result of a mutation that occurs in somatic cells?

A)The mutation will be passed along to the organism's offspring.
B)The mutation may be expressed in the individual, but will not be passed along to its offspring.
C)The mutation will be deleterious.
D)There will never be any visible effect.
E)The mutation will prevent all reproduction.

Answer 1

B

Question 2

A population in biology refers to a group of organisms in the same geographic area that:

A)are different species.
B)are genetically related.
C)are the same species.
D)have the similar phenotype.
E)cannot interbreed.

Answer 2

C

Question 3

What kind of mutation has no effect on an organism's ability to survive or reproduce?

A)a deleterious mutation
B)a neutral mutation
C)an advantageous mutation
D)an adapted mutation

Answer 3

B

Question 4

Which of the following would be considered an advantageous mutation?

A)a mutation that makes an individual more visible to predators
B)a mutation that increases an organism's ability to find food
C)a mutation that decreases the offspring's chance of survival
D)a mutation that changes hair color in humans
E)a mutation that causes increased susceptibility to a disease

Question 5

Which of the following research questions would a population geneticist be MOST likely to ask?

A)How much genetic variability is found in sperm whales?
B)How can we explain the amount of genetic diversity in Adelie penguins?
C)Why do some species have more genetic diversity than others?
D)All of these choices are correct.

Question 6

Genetic variation has two sources-mutation and:

A)recombination.
B)natural selection.
C)genetic drift.
D)non-random mating.
E)cell division.

Question 7

Which of the following is a source of genetic variation?

A)recombination
B)bottlenecks
C)natural selection
D)genetic drift
E)adaptations

Question 8

As a population geneticist, you find a species of snails with more genetic diversity than humans. What does this mean?

A)The snails have more genes on their chromosomes than humans.
B)There is more variety in the gene pool of snails than humans.
C)The snails have more DNA than humans.
D)The snails have more mutations occurring than humans.
E)There is not enough information provided to answer this question.

Question 9

Interbreeding groups of organisms of the same species living in the same geographical area are called:

A)populations.
B)gene pools.
C)fixed groups.
D)randomly mating groups.

Question 10

Which of the following may be a characteristic of a beneficial mutation?

A)It facilitates successful reproduction.
B)It decreases lifetime reproductive output.
C)It has no effect on phenotype.
D)It decreases an organism's fitness.

Question 11

Genetic variation in a population refers to which of the following?

A)multiple individuals breeding together
B)multiple alleles within a gene pool
C)multiple phenotypes with the same genotype
D)multiple genes within a genome
E)multiple offspring with advantageous mutations

Question 12

All the alleles present in all individuals in a species are referred to as the _____ of that species.

A)gene pool
B)allele frequency
C)genotype frequency
D)genotype
E)phenotype

Question 13

Humans are considered to be the most genetically diverse organisms on Earth, and possess considerably more genetic variation compared to any insect or avian species.

Question 14

Why is genetic variation critical for evolution?

A)It is required for mutations.
B)It is the source material for natural selection.
C)It is essential for adaptation.
D)It is essential for genetic recombination.
E)It is not critical for evolution.

Question 15

What is one reason why many mutations may be deleterious?

A)Because the genetic code has redundancy built in.
B)Because if a mutation changes the primary structure of a protein, the protein may no longer work.
C)Because the body has no way to detect or correct mutations.
D)Most mutations are actually beneficial, not deleterious.
E)Any change in the DNA sequence means that DNA no longer functions properly.

Question 16

Consider a population of killer whales. The gene pool of this population would only contain alleles harboring beneficial or neutral mutations, as deleterious mutations are efficiently eliminated from the gene pool of a species.

Question 17

From an evolutionary perspective, germ-line mutations are more significant than somatic mutations. This is because:

A)somatic mutations affect only one or a few cells.
B)somatic mutations are generally harmful.
C)only germ-line mutations will appear in an individual's descendants.
D)only germ-line mutations are potentially beneficial.
E)somatic mutations affect only one or a few cells and only germ-line mutations will appear in an individual's descendants.

Question 18

A gene pool is comprised of what?

A)all the genes in a population
B)all the alleles within a population
C)all the individuals within a population
D)all the offspring within a population

Question 19

Mutations in skin cells that result in melanoma are considered _____ mutations; a mutation that can be passed on from parent to offspring are referred to as a _____ mutation.

A)somatic; germ-line
B)germ-line; somatic
C)deleterious; somatic
D)germ-line; beneficial
E)deleterious; beneficial

Question 20

In genetics, two organisms are part of the same population if:

A)they are the same species.
B)they are from different gene pools.
C)they have the same phenotype.
D)they are in the same geographic area.
E)they are the same species and are in the same geographic area.

Question 21

Imagine you are studying a population of plants and you have determined that they are all genetic clones of one another. You are interested in a particular gene found in the population that you have named LLT (low-light tolerance), that allows it to live in shady areas. What is the frequency of this allele in the population you study?

A)0)5
B)1)0
C)0)0
D)It is not possible to determine the allele frequency with the information provided.

Question 22

How does gel electrophoresis allow researchers to observe genetic variation?

A)Gel electrophoresis enables a scientist to identify dominant and recessive traits.
B)Gel electrophoresis enables scientists to identify alleles that vary.
C)Gel electrophoresis enables scientists to replicate a strand of DNA.
D)Gel electrophoresis enables a scientist to link phenotype to genotype.
E)Protein gel electrophoresis enables a scientist to sequence DNA.

Question 23

Using protein gel electrophoresis to measure genetic variation in populations has some drawbacks. Which of the following is/are problems with the technique?

A)It can't detect synonymous mutations. That is, differences in DNA sequences that result in the same amino acid sequence can't be detected with this method.
B)It can't detect differences in noncoding DNA.
C)It can only be used with proteins that can be stained or otherwise labeled and visualized.
D)It can't detect mutations that do not affect the mobility of a protein within the gel, even if the protein's amino acid sequence is changed.
E)None of the answer options is correct.

Question 24

The blood type A can be produced by what genotypes?

A)AO
B)AB
C)BA
D)OO
E)BB

Question 25

A gene in a diploid species has five different alleles. In any one population, the allele frequencies of all five alleles must add up to:

A)one.
B)two.
C)five.
D)ten.

Question 26

Human ABO blood groups are determined by a single gene with 3 alleles: A, B, and O. In a sample of 300 individuals, 100 are blood type A and genotype AA, 100 are blood type B and genotype BO, and 100 are blood type O and genotype OO. What are the allele frequencies?

A)33.3% A, 33.3% B, 33.3% O
B)33.3% A, 33.3% B, 66.6% O
C)33.3% A, 16.6% B, 50% O
D)25% A, 25% B, 50% O
E)50% A, 25% B, 25% O

Question 27

An individual that is homozygous for an allele will produce two bands on an electrophoresis gel.

Question 28

In a hypothetical population of 1000 frogs there exists a gene with two alleles. 280 of the frogs are homozygous dominant (DD), and 220 are homozygous recessive (dd). What is the frequency of heterozygotes in the population?

A)0)0
B)0)28
C)0)22
D)0)50

Question 29

Why is DNA sequencing the gold standard for measuring genetic variation?

A)It is the easiest method of identifying genetic variation.
B)It uses mutations to detect differences in amino acid sequence.
C)It relies on proteins instead of genetic sequence.
D)It determines the exact genetic sequence, and thus the absolute variation in a population.
E)It is the least accurate, and is not the gold standard.

Question 30

With few exceptions, we cannot use observable traits to measure the amount of genetic variation in populations because:

A)observable traits do not vary enough among individuals to measure.
B)we cannot identify enough observable traits to be useful, even if they could be measured.
C)many traits are encoded by large numbers of genes.
D)observable traits are products of the environment as well as the genome.
E)many traits are encoded by large numbers of genes, and observable traits are products of the environment as well as the genotype.

Question 31

Using visual observation of phenotypes to identify allele frequency rarely works because:

A)most alleles are recessive and will not produce a visible phenotype.
B)phenotype is not due to the alleles.
C)multiple genes may control the phenotype.
D)visual phenotypes are rare.
E)phenotype is not an indication of genotype.

Question 32

The allele frequency of all the alleles of a gene present in the population must add up to 1.

Question 33

In general, in a sample of n individuals, the frequency of an allele is:

A)the number of occurrences of the allele.
B)the number of occurrences of the allele divided by n.
C)n)
D)the number of occurrences of the allele divided by twice the number of individuals in the sample (2n).
E)twice the number of occurrences of the allele divided by n.

Question 34

If the allele frequency for the recessive single allele that causes a particular rare hair color is 0.02, how frequently would you expect the hair color to be present in humans?

A)1 in every 50 individuals
B)1 in every 2000 individuals
C)1 in every 2500 individuals
D)1 in every 5000 individuals

Question 35

Allele frequency can be measured using what technique?

A)observation of phenotype
B)gel electrophoresis
C)DNA sequencing
D)All of these choices are correct.

Question 36

An example of a phenotypic trait that allows identification of the genetic variation coding for the phenotype is:

A)human sprinting speed.
B)human skin color.
C)human blood type.
D)human height.

Question 37

In a hypothetical population of 1000 frogs there exists a gene with two alleles. 280 of the frogs are homozygous dominant (DD), and 220 are homozygous recessive (dd). What is the frequency of the D allele in the population?

A)0)47
B)0)50
C)0)53
D)The answer cannot be determined from the data provided.

Question 38

Why can't we measure genetic variation in a population using observable traits (phenotypes)?

A)Many traits are encoded by multiple genes.
B)Phenotypes are not determined by genes.
C)The environment can also affect the phenotype.
D)All traits are encoded by a single gene.

Question 39

Recall that in Mendel's garden peas, the yellow gene determines flower color, with the A (yellow) allele dominant to the a (green) allele. In a population of 200 plants, the genotype frequencies are 50% AA, 25% Aa, and 25% aa. What are the allele frequencies?

A)50% A, 50% a
B)50% A, 25% a
C)87.5% A, 12.5% a
D)62.5% A, 37.5% a
E)75% A, 25% a

Question 40

What does it mean to say that an allele is "fixed" in the population?

A)It has been repaired by typical mechanisms in the cell.
B)It is an indication of no genetic variation at that locus in the population.
C)It is an indication of low genetic variation at that locus in the population.
D)It is an indication of high genetic variation at that locus in the population.
E)It is an indication that locus cannot undergo mutation.

Question 41

If there are 100 individuals in a population and 20 are homozygous for B, 60 are heterozygous, and 20 are homozygous for b, what is the allele frequency of B?

A)20%
B)40%
C)50%
D)80%
E)The frequency of B can't be calculated with the provided information.

Question 42

You have two populations of flowering plants. In these populations floral color is controlled by one gene. The red gene (R) is dominant to the white gene (r). In population 1, 75% of the flowers are red, in population 2 25% of the flowers are white. Assuming the population is in Hardy-Weinberg equilibrium, which population has a greater frequency of the R allele?

A)population 1
B)population 2
C)Neither; they both have the same frequency.

Question 43

A population that exhibits only one allele at a particular gene is:

A)fixed for that allele.
B)undergoing evolution.
C)in Hardy-Weinberg equilibrium.
D)experiencing natural selection.
E)undergoing genetic drift.

Question 44

In a given population of individuals with a particular gene of interest, the allele frequencies for that gene are equal (there are only two alleles for this gene: A and a). What are the expected genotype frequencies, assuming the population is in Hardy-Weinberg equilibrium?

A)AA = 0.5, aa = 0.5
B)AA = 0.25, Aa = 0.50, aa = 0.25
C)The answer cannot be determined because the allele frequencies are not provided.

Question 45

In a given population, all humans have the same blood type O. If no other alleles for blood type exist in this population, this population is "fixed" for the O allele.

Question 46

In a population of Mendel's garden peas, the frequency of the dominant A (yellow flower) allele is 80%. Let p represent the frequency of the A allele and q represent the frequency of the a allele. Assuming that the population is in Hardy-Weinberg equilibrium, what are the genotype frequencies?

A)64% AA, 32% Aa, 4% aa
B)50% AA, 25% Aa, 25% aa
C)16% AA, 40% Aa, 44% aa
D)75% AA, 15% Aa, 10% aa
E)80% AA, 10% Aa, 10% aa

Question 47

You have a small population of beetles. One day a large rainstorm causes flooding and wipes out 87% of the population. The remaining individuals have much lower genetic variation than the original population. Which of the following would explain the lack of Hardy-Weinberg equilibrium seen after the flood?

A)founder effect
B)random mating
C)small population size
D)genetic drift
E)migration

Question 48

Positive selection increases the frequency of an allele (until it goes to fixation) and negative selection decreases the frequency of an allele (until it is eliminated). What is the long-term fate of either allele of a gene with two alleles in which the fitness of the heterozygote is superior to that of both homozygotes?

A)One allele will eventually go to fixation because it is still more favored than the other with the given selective environment.
B)Both alleles will remain in the population because heterozygote gametes will form with each allele in a separate gamete.
C)Heterozygote advantage will continue until the frequency of both alleles is equal to 0.5.
D)One of the alleles will eventually be lost because selection will favor the other allele.

Question 49

When calculating the allele frequency of allele A in a population, why do you multiply the frequency of individuals who are homozygous for A by 2?

A)Because if A is dominant, it will show up twice as much.
B)Because each individual who is homozygous for A has two copies of the allele.
C)Because there are always twice as many homozygous individuals as heterozygous individuals.
D)Because individuals homozygous for A will produce twice as many offspring.
E)Because individuals homozygous for A will be twice as likely to survive.

Question 50

Mutations are the ultimate source of genetic variation. However, they usually occur at very low frequencies. Assume a mutation resulting in a novel allele occurs in a gene in one individual in a population of 500 diploid individuals. What is the frequency of the new allele?

A)0)05
B)0)005
C)0)01
D)0)001

Question 51

If a gene has two alleles, and allele A has a frequency of 83%, then allele a has a frequency of:

A)17%.
B)117%.
C)41.5%.
D)7%.
E)166%.

Question 52

In a population of Mendel's garden peas, the frequency of the dominant A (yellow flower) allele is 80%. Let p represent the frequency of the A allele and q represent the frequency of the a allele. Assuming that the population is in Hardy-Weinberg equilibrium, what are the genotype frequencies?

A)64% AA, 32% Aa, 4% aa
B)50% AA, 25% Aa, 25% aa
C)16% AA, 40% Aa, 44% aa
D)75% AA, 15% Aa, 10% aa
E)80% AA, 10% Aa, 10% aa

Question 53

Because one of the conditions of Hardy-Weinberg equilibrium is to have a large population, small populations, by definition, violate that principle. Why is that important?

Question 54

What is the fundamental concept that causes gel electrophoresis of proteins to work?

A)Different proteins have different charges and sizes.
B)Different proteins respond in the same way to dyes in a gel.
C)Some proteins are enzymes and will react with molecules in the gel.
D)All proteins have the same charge and will move through the gel at the same speed.
E)All proteins will react with a dye to produce a band.

Question 55

A researcher is studying the color of grasshopper exoskeletons. Assume that this phenotype is caused by the action of two alleles. Green grasshoppers have the genotype AA and brown grasshoppers have the genotype aa. If the frequency of the A allele in this population is 0.2, what is the frequency of the a allele?

A)0)8
B)0)2
C)0)1
D)0)4
E)0)6

Question 56

In a study of genetic variation at the Graceland gene, a researcher finds that there are two alleles in a population. In a large sample (500 individuals), the frequency of heterozygotes is 0.63. Is the population in Hardy-Weinberg equilibrium?

A)No. The frequency of heterozygotes would be 1 if the population was in Hardy-Weinberg equilibrium.
B)No. The highest frequency of heterozygotes under Hardy-Weinberg equilibrium is 0.5.
C)No. There would be no heterozygotes if the population was in Hardy-Weinberg equilibrium.
D)No. The frequency of each genotype would be equal if the population was in Hardy-Weinberg equilibrium.

Question 57

What were some of the characteristics of protein gel electrophoresis?

A)This method can detect genetic variation in a variety of proteins, including enzymes and most transcription factors.
B)This method can identify a variety of mutations in proteinsones that affected protein mobility, structure, or function.
C)This method can identify mutations in noncoding DNA.
D)This method can initially only detect genetic variation in enzymes, as only these proteins could be easily visualized on a gel.
E)This method can only identify mutations in proteins that altered several amino acids.

Question 58

Small populations of a diminutive rodent, each with 100 individuals, live on two small neighboring islands, Rack and Oon. The Rack population is fixed for the A allele at the Agility gene; the Oon population is fixed for the a allele at the Agility gene. Ten individuals from Rack get carried on a drifting fallen tree trunk to Oon. Assuming the drifting individuals arrived at the start of the breeding season and that the rodents breed every year and die once they've raised their offspring, what are the genotype frequencies in the Oon population the year after the accidental migration event?

A)AA 0.0; Aa 0.0; aa 1.0
B)AA (1/11)²; Aa 2(1/11)(10/11); aa (10/11)²
C)AA (10/11)²; Aa 2(1/11)(10/11); aa (1/11)²
D)AA 1.0; Aa 0.0; aa 1.0
E)The genotype frequencies cannot be determined from the information provided.

Question 59

What conditions must be met for alleles to be found in Hardy-Weinberg equilibrium? How much change is expected in a population that is in Hardy-Weinberg equilibrium?

Question 60

You are given the following information about a population: • There are two alleles: C and c.
• C codes for green hair and c codes for white hair.
• C is dominant over c.
• The frequency of the c allele is 0.3.
• The population is comprised of 100 individuals.
Assuming the population is in Hardy-Weinberg equilibrium, how many individuals have green hair?

A)49% of the population will have green hair.
B)81% of the population will have green hair.
C)9% of the population will have green hair.
D)51% of the population will have green hair.

Question 61

You can use Hardy-Weinberg to calculate allele frequencies, but not genotype frequencies.

Question 62

Consider the following two populations and the frequencies of alleles at the FGFR-1 locus. $$\begin{array} { | l | l | l | l | l | } \hline & \text { Allele 1 } & \text { Allele 2 } & \text { Allele 3 } & \text { Allele 4 } \\\hline \text { Population 1 } & 0.25 & 0.25 & 0.25 & 0.25 \\\hline \text { Population 2 } & 0.50 & 0.42 & 0.05 & 0.03 \\\hline\end{array}$$ Which of the populations has greater allelic variation?

A)population 1
B)population 2
C)Neither, allelic diversity is the same for both populations.

Question 63

_____ refers to a system in which individuals select their mates according to phenotype.

A)Nonrandom mating
B)Random mating
C)Differential mating
D)Sexual selection
E)All of these choices are correct.

Question 64

You find that a wild population of antelope is not in Hardy-Weinberg equilibrium. From this information alone, can you determine the mechanism of evolution operating on the population?

A)yes
B)no

Question 65

Hardy-Weinberg can predict genotype frequencies from _____ frequencies.

A)allele
B)advantageous mutation
C)deleterious mutation
D)chromosome
E)phenotype

Question 66

A population that is in Hardy-Weinberg equilibrium is evolving.

Question 67

Which of the following is NOT an assumption of Hardy-Weinberg equilibrium?

A)Individuals must select mates nonrandomly.
B)No selection must be taking place.
C)Mutations are not occurring.
D)Populations must be large.
E)Individuals are not entering or leaving the population.

Question 68

When the conditions of the Hardy-Weinberg equilibrium are met:

A)evolution occurs.
B)evolution does not occur.
C)gene frequencies in the population change over time.
D)gene frequencies in the population do not change over time.
E)none of these occurs when conditions of the Hardy-Weinberg equilibrium are met.

Question 69

The differential success of alleles is called:

A)selection.
B)genetic drift.
C)fixation.
D)migration.
E)evolution.

Question 70

At the genetic level, evolution is:

A)a change in fitness over time.
B)a population change over time.
C)a change in the frequency of an allele or genotype over time.
D)an increase in fitness over time.
E)natural selection.

Question 71

If an assumption for the Hardy-Weinberg equation is violated, what does this mean?

A)The allele frequencies or genotype frequencies are undergoing evolutionary change.
B)The population is adapted to its environment.
C)Mutations are increasing in frequency in the population.
D)An allele is fixed in the population.

Question 72

What term CORRECTLY describes change in allele frequency due to random effect of a small population?

A)mutation
B)selection
C)nonrandom mating
D)genetic drift
E)immigration

Question 73

When we say "populations evolve, not individuals," what does this mean?

A)Evolution does not happen.
B)Individuals cannot change their genetic makeup, but genotype frequencies in a population can change.
C)Evolution is a change in the genetic make-up of individuals over time.
D)Only alleles change over time, not genotype frequencies.
E)Only genotype frequencies change over time, not allele frequencies.

Question 74

Which of these five evolutionary forces is rare and usually NOT considered by population geneticists?

A)mutation
B)selection
C)nonrandom mating
D)genetic drift
E)immigration

Question 75

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

A)no differences in the survival and reproductive success of individuals
B)no migration
C)no mutation
D)random mating
E)All of these choices are correct.

Question 76

What does the term 2pq represent in the Hardy-Weinberg relation?

A)the frequency of homozygous dominant individuals
B)the frequency of heterozygotes
C)the frequency of homozygous recessive individuals
D)the frequency of deleterious mutations

Question 77

How can evolution of a population occur without changing the allele frequency of a trait within the population?

A)There is no mutation.
B)More organisms enter the gene pool.
C)The genotype frequencies of the population change over time.
D)The population is small.

Question 78

If a population is not in Hardy-Weinberg equilibrium, we can conclude that:

A)nonrandom mating has occurred.
B)natural selection has occurred.
C)one of the assumptions of the Hardy-Weinberg equilibrium has been violated.
D)evolution has occurred because one or more of the assumptions of the Hardy-Weinberg equilibrium has been violated.
E)All of these choices are correct.

Question 79

In a population of Mendel's garden peas, the frequency of dominant yellow-flowered plants is 50%. The population is in Hardy-Weinberg equilibrium. From this information alone, can you determine the allele frequencies (A = p and a = q)? Why or why not?

Question 80

In a population of Mendel's garden peas, the frequency of green-flowered plants (genotype aa) is 49%. The population is in Hardy-Weinberg equilibrium. What are the frequencies of the AA and Aa genotypes?

A)49% AA, 2% Aa
B)9% AA, 42% Aa
C)42% AA, 9% Aa
D)33% AA, 18% Aa
E)The frequencies cannot be determined from the information provided.