Deck 4: Genes and Their Evolution: Population Genetics

Question 1

________ is the force of evolution that is most powerful when acting on very small populations.

A)Gene flow
B)Mutation
C)Genetic drift
D)Founder effect

Answer 1

Genetic drift

Question 2

Which of the following is the result of a single-point mutation on chromosome 11?

A)Marfan syndrome
B)Down syndrome
C)Kleinfelter's syndrome
D)Sickle-cell anemia

Answer 2

Sickle-cell anemia

Question 3

When geneticists talk about the gene pool, they refer specifically to variation at a genetic

A)chromosome.
B)nucleus.
C)address.
D)locus.

Answer 3

locus.

Question 4

Malaria is caused by

A)bites from infected mosquitoes.
B)a genetic mutation.
C)drinking bad water.
D)eating spoiled food.

Question 5

Which of the following is key to the development of individual species?

A)Microevolution
B)Gene flow
C)Reproductive isolation
D)Equilibrium

Question 6

Which of the following is not a genetic disorder that decreases susceptibility to malaria?

A)G6pd deficiency (favism)
B)sickle-cell anemia
C)Huntington's chorea
D)thalassemia

Question 7

Evolution can best be defined as

A)the appearance of a new species.
B)a change in allele frequencies in a breeding population over time.
C)changes in the DNA of an individual over his or her lifetime.
D)a process that occurs only over extremely long periods of time.

Question 8

Spontaneous mutations are defined as

A)errors caused by some external agent such as X-rays or exposure to toxic chemicals.
B)errors caused by random changes in DNA.
C)errors occurring during mitosis.
D)b and c only.

Question 9

Population geneticists refer to a reproductive population as a(n)

A)allelic pool.
B)deme.
C)micropopulation.
D)macropopulation.

Question 10

The ABO and MN blood-type frequencies of the Dunkers differ significantly from those of current American and German populations due to

A)genetic drift.
B)natural selection.
C)gene flow.
D)mutation.

Question 11

Hardy-Weinberg equilibrium assumes

A)strong selection pressure on the trait(s) being studied.
B)a significant mutation rate from generation to generation.
C)gene flow that is equal both into and out of the population.
D)no gene flow, mutation, genetic drift, or natural selection.

Question 12

When individuals of the same species are reproductively isolated, genetic differences may accumulate in sufficient number so that new species could emerge.Such an event would be an example of

A)microevolution.
B)founder effect.
C)equilibrium.
D)macroevolution.

Question 13

Which African people's southern migration may have led to a significant increase in the incidence of malaria?

A)Masai
B)Turkana
C)Efe
D)Bantu

Question 14

In certain species of nonhuman primates there are groups where only one dominant female has access to mates.The other females must wait until the opportunity to gain mate access presents itself.This will have direct impacts on "fitness," influencing which of the following?

A)reproductive success
B)aggressiveness
C)strength
D)age at death

Question 15

The type of selection that favored progressively larger brain size in human evolution is

A)natural selection.
B)directional selection.
C)stabilizing selection.
D)disruptive selection.

Question 16

The effects of ________ have increased from 10,000 years ago to the present.

A)mutations
B)gene flow
C)genetic drift
D)natural selection

Question 17

Klinefelter's syndrome results

A)from males passing on an extra copy of chromosome #21.
B)from females passing on an extra copy of chromosome #21.
C)from females passing on an extra copy of the Y chromosome (resulting in a 47-chromosome, XXY karyotype).
D)from males passing on an extra copy of the X chromosome (resulting in a 47-chromosome, XXY karyotype).

Question 18

Together, all of the alleles contained within a group of interbreeding individuals are known as a

A)gene pool.
B)population.
C)clinal distribution.
D)polymorphism.

Question 19

Mutation

A)works most effectively on small populations.
B)is the only source of new alleles.
C)is one of many sources of new alleles.
D)works to decrease variation between populations.

Question 20

While conducting research with a small population in South America you note that an overwhelming majority of individuals exhibit signs of a specific genetic abnormality.This is most likely the result of

A)natural selection.
B)founder effect.
C)extinction.
D)gene flow.

Question 21

A random change in allele frequencies over time is known as

A)genetic drift.
B)gene flow.
C)admixture.
D)gene migration.

Question 22

Spontaneous mutation is the result of

A)unknown causes.
B)X-rays.
C)toxic chemicals.
D)UV radiation.

Question 23

The evolution of the modern horse with a single hoof on each limb from a dog-sized ancestor with multiple digits is an example of

A)macroevolution.
B)stabilizing selection.
C)disruptive selection.
D)microevolution.

Question 24

You and your friend are reading a scientific article about cheetahs that have stripes instead of spots.The article refers to this as a genetic mutation.Your friend wonders why the striped cheetahs are not referred to as a new species.You respond:

A)The article is mistaken.Striped cheetahs are clearly a new species.
B)Genetic mutations only cause superficial changes that do not result in evolutionary advantages.
C)When the frequency of striped individuals in the population reaches 50%, they will be categorized as a new species.
D)The stripes are caused by an individual mutation, and have not evolved in a reproductively isolated population.

Question 25

A point mutation that does not result in a change to the amino acid coded for is said to be a

A)spontaneous mutation.
B)synonymous mutation.
C)selective mutation.
D)stabilizing mutation.

Question 26

Evolution is caused by which of the following?

A)mutation
B)gene flow
C)genetic drift
D)all of the above

Question 27

Transposable elements are DNA sequences that

A)are not coded to produce proteins.
B)contain numerous point mutations.
C)occur only on the X and Y chromosomes.
D)insert themselves into other parts of the genome.

Question 28

What effect does natural selection have on population variation?

A)increases variation
B)decreases variation
C)both increases and decreases variation
D)does not affect variation

Question 29

Another name for the evolutionary force called gene flow is

A)founder effect.
B)disruptive selection.
C)admixture.
D)transposition.

Question 30

The absence of the A and B alleles in Native American populations is a result of

A)natural selection.
B)gene flow.
C)founder effect.
D)mutation.

Question 31

Mutations to which of the following cells are most likely to have significant evolutionary consequences?

A)sex cells (gametes)
B)red blood cells
C)skin pigment cells
D)brain cells

Question 32

Aborigines are an endogamous society.This means that marriage and reproduction take place within the group leading to

A)increased genetic diversity through genetic drift.
B)migration without gene flow.
C)more genetic diversity than would be observed in an exogamous society.
D)decreased genetic diversity due to a lack of admixture.

Question 33

Studies of Darwin's finches have found that at certain points in time all finches on the island have either wide beaks or sharp, narrow beaks.The type of evolution that leads to this phenotype distribution is

A)directional selection.
B)natural selection.
C)disruptive selection.
D)stabilizing selection.

Question 34

The best-documented case of industrial melanism involves

A)Galápagos finches.
B)dung beetles.
C)monarch butterflies.
D)peppered moths.

Question 35

Over a period of two generations, the frequency of green dung beetles in a population shifts from 75% to 71% while the frequency of brown dung beetles within this population shifts from 25% to 29%.This is an example of

A)minievolution.
B)microevolution.
C)millievolution.
D)nanoevolution.

Question 36

Patrilocal societies are expected to display

A)greater mtDNA diversity than Y chromosome diversity.
B)roughly equivalent mtDNA and Y chromosome diversity.
C)greater Y chromosome diversity than mtDNA diversity.
D)no strong correlation between societal structure and genetic diversity (none of the above).

Question 37

Which of the evolutionary forces is most likely to decrease variation between populations?

A)gene flow
B)founder effect
C)mutation
D)natural selection

Question 38

The malarial parasite is transmitted to humans by

A)dirty drinking water.
B)mosquitoes.
C)rats.
D)monkeys.

Question 39

The clinal decrease in type B blood from East Asia to Western Europe is probably the result of

A)founder effect.
B)stabilizing selection.
C)mutation.
D)gene flow.

Question 40

Fitness trade-off refers to selection favoring which genotype?

A)homozygous dominant
B)homozygous recessive
C)heterozygous
D)no genotype is favored

Question 41

Explain how the founder effect can lead to a descendant population that differs greatly from its parent population over a relatively short period of time.

Question 42

An individual who displays the disease sickle-cell anemia must have inherited the deleterious allele from both phenotypically normal parents.This individual is therefore

A)homozygous dominant.
B)homozygous recessive.
C)heterozygous.
D)haplozygous.

Question 43

A study of Darwin's finches after a long period of drought found that all species of finch on one of the islands developed wide beaks in order to break open seeds.The type of evolution that leads to this phenotype distribution is

A)directional selection.
B)natural selection.
C)disruptive selection.
D)stabilizing selection.

Question 44

A genetic study conducted over multiple generations found that the frequency of genotypes in the first generation were AA: 0.36, Aa: 0.48, aa: 0.16.In the second generation, genotype frequencies shifted to AA: 0.16, Aa: 0.48, aa: 0.36.According to the Hardy-Weinberg equilibrium, we can assume

A)random mating has altered gene frequencies.
B)gene flow has possibly shifted the gene frequencies.
C)mating in this population must be nonrandom mating.
D)both b and c

Question 45

Familial hypercholesterolemia, an autosomal dominant disease, is five times more frequent in the Afrikaner population of South Africa than in the population of Europe or the United States.This represents an example of

A)natural selection.
B)bottle neck.
C)founder effect.
D)kin selection.

Question 46

Why is a frameshift mutation far more likely to lead to a defective protein compared with a point mutation?

Question 47

In a classroom taste-test for PTC, the genotype frequency was determined to be P = 0.35 and Q = 0.65.After applying the Hardy-Weinberg equation, which of the following was found to be the percentage of genotypes?

A)p2=0.12; 2pq=0.46; q2=0.42
B)p2=0.35; 2pq=0.00; q2=0.65
C)p2=0.12; 2pq=0.65; q2=0.23
D)None of the above

Question 48

Why is the incidence of sickle-cell anemia an excellent example of a "balanced polymorphism," in which two or more alleles are maintained by natural selection in a population?

Question 49

Why is the peppered moth an excellent example of directional selection?

Question 50

The mutation known as trisomy 21, in which an extra copy of chromosome 21 is present, is more commonly known as

A)Turner syndrome.
B)Down syndrome.
C)Klinefelter's syndrome.
D)Williams syndrome.

Question 51

A genetic study conducted over two generations found that the frequency of genotypes in the first generation were AA: 0.36, Aa: 0.48, aa: 0.16.In the second generation, genotype frequencies remained the same.According to the Hardy-Weinberg equilibrium, we can assume

A)negative assortative mating has maintained gene frequencies.
B)mutations have likely occurred resulting in the same frequency.
C)mating in this population is random.
D)the population is small and we cannot detect change.