Deck 20: Genes Within Populations

Question 1

In the Hardy-Weinberg equation, p and q are _____.

A)genotypes
B)mutation rates
C)phenotypes
D)allele frequencies

Answer 1

D

Question 2

In the graph above, how can the change in infant mortality be explained as birth weight increases from 2 to 7 pounds?

A)A larger baby will have more developed organs and thus have greater fitness.
B)A baby closer to 7 pounds will have more developed organs and thus have lower mortality.
C)A baby closer to 2 pounds will not be able to be delivered safely and thus have lower mortality.
D)A baby closer to 7 pounds will have more developed organs and thus have higher motality.

Answer 2

A

Question 3

The frequency of a particular allele within a population can be changed, over time, by

A)genetic outflow.
B)large population size.
C)selection.
D)inheritance of acquired characteristics.

Answer 3

C

Question 4

The observation that most pureblood Native Americans have type O blood is best explained by _____

A)gene flow.
B)assortative mating.
C)genetic drift.
D)a founder effect.

Question 5

You spray your kitchen with an insecticide to kill the cockroaches.A few survive and reproduce, producing a large healthy population in a few generations that all have similar genetic backgrounds.This is an example of _____

A)assortative mating.
B)bottleneck effect.
C)mutation.
D)migration.

Question 6

"The inheritance of acquired characteristics" proposal was put forward by

A)Hardy-Weinberg.
B)Darwin.
C)Founder.
D)Lamarck.

Question 7

Genotypes are said to be in ___________ equilibrium if there is random mating and no other forces tend to alter the proportions of alleles from one generation to the next.

A)Mendelian
B)Hardy-Weinberg
C)steady state
D)homeostatic

Question 8

Hardy-Weinberg pointed out that the original proportions of the genotypes in a population would remain constant from generation to generation if certain assumptions are met.Which one of the following is not a Hardy-Weinberg condition?

A)No gene flow occurs.
B)Random mating occurs.
C)No polymorphic loci exist in the population.
D)No selection occurs.

Question 9

For a gene with two alternative alleles, A (with a frequency of p) and B (with a frequency of q), the term in the algebraic form of the Hardy-Weinberg equilibrium for the heterozygote genotype frequency is

A)p².
B)q².
C)2pq.
D)(p+q)².

Question 10

Natural selection for a certain phenotype will affect the _____ .

A)genotype of an individual
B)genotype of a population
C)allele frequency of an individual
D)allele frequency of a population

Question 11

Female cardinals select male mates in part based on their bright red color.What effect would this have on a cardinal population that was in Hardy-Weinberg equilibrium?

A)The red allele frequencies would decrease because of equilibrium.
B)The frequency of red alleles would be less than those predicted by Hardy-Weinberg equilibrium.
C)The frequency of red alleles would be greater than those predicted by Hardy-Weinberg equilibrium.
D)The frequency of red alleles would be equal to those predicted by Hardy-Weinberg equilibrium.

Question 12

Reproductive success of an individual is known as:

A)variation.
B)adaptive makeup.
C)fitness.
D)microevolution.

Question 13

In a small population of cockroaches living in your kitchen, only a few roaches mate in one year.This can lead to random changes in allele frequency in the population through ______

A)nonrandom mating.
B)selection.
C)genetic drift.
D)mutation.

Question 14

The presence of the disease sickle cell anemia illustrates that natural selection does not always eliminate _________ alleles.

A)polymorphic
B)dominant
C)neutral
D)recessive

Question 15

Moths that can evade a bat's echolocation have _____ that increase their likelihood of survival and reproduction.

A)fitness
B)selection
C)mutations
D)adaptations

Question 16

There are more than 30 blood group genes in humans, in addition to the ABO locus.This increases ____ in human populations.

A)genetic variability
B)homozygosity
C)selective mating
D)gene flow

Question 17

In the graph above, which baby characteristics would explain the percent infant mortality curve and any subsequent effects on fitness?

A)The smaller the baby the better the chance of survival.
B)The baby needs to be small enough to survive after birth, but large enough for a safe delivery.
C)The baby needs to be large enough to survive after birth, but small enough for a safe delivery.
D)There is no correlation between birth weight and survival.

Question 18

Two parents who do not have sickle cell anemia have a child that has the disease.The parents are both:

A)homozygous for the sickle cell allele.
B)heterozygous for the sickle cell allele.
C)homozygous for the normal allele.
D)epistatic for the sickle cell allele.

Question 19

When fisheries managers move fish from one lake to another, this causes gene ______.

A)mutation
B)blending
C)flow
D)dominance

Question 20

The key point in Darwin's proposal is that the ___________ imposes the conditions that determine the direction of selection.

A)gene
B)environment
C)parent
D)individual

Question 21

Coloration in the peppered moth (Biston betularia) is determined by a single gene with two alleles showing complete dominance.Dark moths are homozygous dominant or heterozygous for the gene, light moths are homozygous recessive.In a sample of 100 moths, you determine that 64 of the moths are dark.According to the Hardy-Weinberg rule, the expected frequency of the dominant allele is ___.

A)0.4
B)0.36
C)0.6
D)0.64

Question 22

In a large population of randomly reproducing rabbits, a recessive allele r comprises 80% of the alleles for a gene.What percentage of the rabbits would you expect to have the recessive phenotype?

A)4%
B)32%
C)64%
D)80%

Question 23

In some instances environmental change causes a situation where one phenotype is favored for a period of time, and then a different phenotype is favored.This oscillating selection causes

A)the maintenance of genetic variation in the population.
B)an increase in point mutations.
C)elimination of rarer genotypes because of uneven selection.
D)extinction of the population.

Question 24

In a forest, trees that get more sunlight grow taller than other nearby trees.This is a form of ______

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

Question 25

An island is on the migration route of sea birds.This island also has abundant tree nesting birds that live on the island permanently and are not found on any other island.The tree nesting birds are more likely than the sea birds to be in Hardy-Weinberg equilibrium because:

A)the sea bird population is larger.
B)there are fewer mutations in the sea birds.
C)mating is random in the tree nesting birds.
D)of high immigration in the sea bird population.

Question 26

People homozygous for the sickle-cell anemia allele develop a life threatening disease, while those homozygous for the normal allele are at the highest risk of dying from malaria.Carriers have some resistance to malaria, but do not develop sickle cell anemia.This is an example of ____

A)founder effect.
B)genetic bottleneck.
C)heterozygosity.
D)heterozygote advantage.

Question 27

In disruptive selection, over time

A)a population increases its variation (e.g., a wide selection of all beak sizes).
B)the population is strongly selected for in two directions (e.g., larger beak size and smaller beak size).
C)a population goes extinct.
D)the most extreme outliers of a population are eliminated (e.g., the largest beaks and smallest beaks are eliminated).

Question 28

The percentage of different colored water boatmen eaten by fish were graphed relative to the frequency of that color in the population.Based on the graph, a population of water boatmen would _____

A)increase in rare genotypes.
B)have no variation in genotype frequencies.
C)lose rare genotypes.
D)increase in size.

Question 29

Cheetahs have been through a genetic bottleneck; evidence for this is that

A)the body is long, thin, and graceful.
B)these cats are members of an endangered species.
C)there is very little genetic variability.
D)little natural selection occurs in this species.

Question 30

If the frequency of an autosomal recessive trait in humans is 1 out of 100 births, what would be the expected frequency of heterozygote carriers for the trait if we assume that the gene is in Hardy-Weinberg equilibrium?

A)0.01
B)0.10
C)0.18
D)0.81

Question 31

You are studying a population of geese in which there are two color phases, brown and gray.Color in this species is controlled by a single gene, with brown dominant to gray.A random sample of 250 geese shows that 210 are brown.What percentage of the brown geese are heterozygous? (Assume that the population is in Hardy-Weinberg equilibrium.)

A)36%
B)43%
C)48%
D)57%

Question 32

Gene flow, defined as the movement of genes from one population to another, can take place by migration, as well as

A)physical movement of genes within an individual by transposons.
B)removing the barriers between the populations.
C)mating between individuals of adjacent populations.
D)mating with certain trait-containing individuals.

Question 33

A human autosomal recessive trait appears in 1 in 100 births.What percent of people are homozygous dominant for this trait?

A)0.01
B)0.10
C)0.18
D)0.81

Question 34

Being born with extra fingers on a hand is called polydactyly.This is more common in some populations in North America than others due to ____.

A)natural selection in favor of extra fingers in these populations
B)random mating with other populations in North America
C)an increase in mutation rate in these populations
D)a founder effect because their ancestors from Europe carried the alleles

Question 35

During a drought on the Galapagos islands, finches with larger beaks were able to crack the large tough seeds produced by plants that survived the dry conditions.This is an example of ____.

A)genetic drift
B)a founder effect
C)stabilizing selection
D)directional selection

Question 36

Some flowering plants cannot self-pollinate which increases their tendency to mate with phenotypically different mates, a process called disassortative mating.What effect would this have on a population in Hardy-Weinberg equilibrium?

A)The population would remain in Hardy-Weinberg equilibrium.
B)A decrease in heterozygotes would be observed.
C)An increase in heterozygotes would be observed.
D)No change homozygotes or heterozygotes would be observed.

Question 37

Animals that select mates that are phenotypically similar will have _____ when compared with Hardy-Weinberg predictions.

A)fewer homozygotes
B)more homozygotes.
C)less natural selection
D)more mutations

Question 38

If a population was in Hardy-Weinberg equilibrium, then ____ would occur in that population.

A)directional selection
B)an increase of recessive alleles
C)no evolutionary changes
D)assortive mating

Question 39

Certain small towns in the western United States have remained isolated and inbred since their settlement many years ago.Some alleles are more common in these communities as compared to the rest of the population.This effect is known as

A)directional selection.
B)artificial selection.
C)founder effect.
D)Hardy-Weinberg principle.

Question 40

In order for natural selection to occur within a population, certain conditions must be met.One such condition is

A)heterozygosity must be very low.
B)frequent mutations that are inherited.
C)phenotypic differences resulting from environmental conditions.
D)phenotypic variations that are genetic.

Question 41

____ would produce the smallest evolutionary change in a given period of time in a population of birds.

A)Mutation
B)Migration
C)Gene flow
D)Assortive mating

Question 42

The California populations of the Northern elephant seal are descendants from a very small population of seals that was over-hunted in the 1890s.Heterozygosity in this population would be expected to be ________ due to _______________.

A)great; a bottleneck effect
B)slight; a bottleneck effect
C)great; assortive mating
D)great; disruptive selection

Question 43

Many male songbirds are brightly colored.However, the color of the birds is determined by a balance of

A)natural selection against bright colors by predation and sexual selection in favor of bright colors.
B)gene flow that reduces bright colors and natural selection in favor of bright colors.
C)mutations that reduce bright colors and sexual selection in favor of bright colors.
D)mutations that reduce bright colors and gene flow in favor of bright colors.

Question 44

An insect population that becomes resistant to a commonly used insecticide is an example of _____.

A)natural selection
B)a founder effect
C)disruptive selection
D)gene flow

Question 45

Average human males are most likely to be attracted to women with a waist to hip ratio of 0.72.Women with this waist to hip ratio are also the most fertile.By being attracted to women with a waist to hip ratio, a male is increasing his chances of having children and thus improve his ____ .

A)longevity
B)gene flow
C)fitness
D)allele frequency

Question 46

Based on the graph above, the color of male guppies can be seen as a balance between positive and negative selections.Bright colors are an advantage in _____, but a disadvantage in _____.

A)attracting mates; avoiding predators
B)attracting mates; finding food
C)finding food; attracting mates
D)avoiding predators; attracting mates

Question 47

A population of lizards lives in a rocky area next to a desert.Some lizards are light colored and blend into the sand.Others are dark and blend into the rocks.What may happen to this population of lizards over time?

A)They may evolve into two separate species as a result of directional selection.
B)They may remain one species as a result of stabilizing selection.
C)They may remain one species as a result of disruptive selection.
D)They may evolve into two separate species as a result of disruptive selection.

Question 48

Both extremes of an array of phenotypes are favored in _____ .

A)directional selection
B)genetic drift
C)gene flow
D)disruptive selection

Question 49

______ could not be involved in gene flow.

A)Hybridization between neighboring populations
B)Gametes dispersed by ocean currents
C)Disassortative mating within a population
D)Wind-blown pollen

Question 50

The several hundred species of picture-winged fruit flies of the Hawaiian Islands are genetically very similar, yet they all differ markedly from their ancestral population in Asia.This is probably an example of _____

A)gene flow.
B)sexual selection.
C)directional selection.
D)founder effect.

Question 51

The midrange of an array of phenotypes is favored in ____.

A)genetic drift
B)disruptive selection
C)gene flow
D)stabilizing selection

Question 52

In the experiment above, guppy color patterns (spots) were measured in populations exposed to increasing amounts of predation.From this you could conclude that ____ .

A)evolutionary changes take millions of years to appear
B)predators are less likely to catch and eat brightly colored guppies
C)predators are more likely to catch and eat brightly colored guppies
D)brightly colored guppies are more likely to reproduce in the presence of predators

Question 53

The disease, sickle-cell anemia is common in malaria-infested areas because individuals that are heterozygous for the gene (AS) have enhanced resistance to malaria over normal individuals (AA).Individuals with severe sickle-cell anemia (SS) usually die before reproduction.If this population moves to an area without malaria, what will happen to the allele frequency of the A allele over time?

A)It will go up because there is no sickle cell anemia.
B)It will go down because there is no malaria.
C)It will go down because there is no sickle cell anemia.
D)It will go up because there is no malaria.

Question 54

A fur color gene in rabbits has a white dominant (W) and brown recessive allele (w).The environment changes suddenly and none of the white rabbits survive.In a population of 10,000 rabbits the initial frequency of W in the pool was 0.7.How many generations would be required to eliminate all W alleles from the population? Assume that there is no mutation and the population meets all other Hardy-Weinberg conditions.

A)1
B)2
C)5
D)20

Question 55

Antigens on red blood cells are hereditary traits that allow blood to be typed in different ways.One system is based on a gene with two alleles, M and N.If the frequency of the M allele in a population is 0.4, then according to the Hardy-Weinberg rule, the expected frequency of the heterozygous MN genotype is ___.

A)0.16
B)0.24
C)0.36
D)0.48

Question 56

Assortative and disassortative mating are similar in that both ____

A)are kinds of selection pressure.
B)change only the expected Hardy-Weinberg genotype frequencies in a population.
C)are examples of random mating.
D)change only the expected Hardy-Weinberg allele frequencies in a population.

Question 57

In early ancestors of the modern giraffe, longer necks allowed animals to reach higher tree branches as food.This would lead to ____ in the ancestral giraffe population.

A)disruptive selection
B)directional selection
C)sexual selection
D)genetic drift