Deck 19: Evolutionary Change in Populations

Question 1

If all of the alleles of a given locus are the same in a population, then what is the frequency of that allele?

A) 0.1
B) 1.0
C) 10.0
D) 100.0
E) 1000.0

Answer 1

B

Question 2

In order to meet the conditions of the Hardy-Weinberg predictions, a population must:

A) be very large.
B) mutate very quickly.
C) have extensive mating rituals.
D) have a large number of immigrants.
E) have a high rate of natural selection.

Answer 2

A

Question 3

The Hardy-Weinberg principle is applicable provided that migration:

A) does not occur.
B) is limited to adults.
C) is limited to juveniles.
D) only occurs during nonreproductive periods.
E) occurs at the beginning of the breeding season.

Answer 3

A

Question 4

If a population of 2000 individuals has 120 aa genotypes, what would the genotype frequency of aa be?

A) 0.006
B) 0.06
C) 0.6
D) 1.6
E) 16

Question 5

What does p ² represent within the Hardy-Weinberg equation?

A) The total alleles in a gene pool
B) The heterozygotes in a population
C) The recessive allele at a given locus
D) The dominant alleles in a given population
E) The homozygous dominant genotype at a given locus

Question 6

In a certain population, the allele frequencies of the M and N blood group alleles are 0.6 and 0.4, respectively. How many of a population of 500 would be expected to have MN blood type if the population is in genetic equilibrium for the MN locus?

A) 200
B) 220
C) 240
D) 260
E) 300

Question 7

Which is the correct equation for the Hardy-Weinberg principle?

A) p ² + 2 pq ² + q ² + q ² = 100
B) 2 p ² + 2 pq + 2 q ² = 1000
C) p ² + 2 p + 2 q + q ² = 1
D) p ² − 2 pq + q ² = 1
E) p ² + 2 pq + q ² = 1

Question 8

In a certain population, the allele causing sickle cell anemia has an allele frequency of 0.2. If the population is in genetic equilibrium for this allele, what fraction of the population would be carriers for the allele (heterozygous individuals)?

A) 0.24
B) 0.32
C) 0.42
D) 0.48
E) 0.80

Question 9

Table 19-1 Refer to the accompanying table. What is the frequency of the Dd genotype?

A) 0.1
B) 0.2
C) 0.4
D) 0.6
E) 0.8

Question 10

What is the study of the genetic variability within a population and the forces that change allele frequencies?

A) evolution
B) allele genetics
C) variable ecology
D) population genetics
E) evolutionary genetics

Question 11

If an animal population is diploid, then each individual possesses:

A) one allele for each locus.
B) two alleles for each locus.
C) three or more alleles for each locus.
D) a partial set of alleles found in each cell.
E) a complete set of alleles found in each chromosome.

Question 12

If a population of 1000 individuals has 120 aa genotypes, 460 Aa genotypes, and 420 AA genotypes, what is the allele frequency of the dominant allele (A)?

A) 0.16
B) 0.43
C) 0.50
D) 0.65
E) 0.88

Question 13

If the allele or genotype frequencies deviate from the values predicted by the Hardy-Weinberg principle, the population is:

A) growing.
B) mutating.
C) migrating.
D) evolving.
E) at equilibrium.

Question 14

A ____ consists of all of the individuals of the same species that inhabit a particular place at the same time.

A) family
B) genotype
C) population
D) ecosystem
E) community

Question 15

Table 19-1
Refer to the accompanying table. What is the frequency of the dd genotype?

A) 0.1
B) 0.2
C) 0.4
D) 0.6
E) 1.2

Question 16

Table 19-1
Refer to the accompanying table. What is the allele frequency of d ?

A) 0.1
B) 0.2
C) 0.4
D) 0.5
E) 0.6

Question 17

For the relative proportions of alleles and genotypes in successive generations to stay the same, which condition must be met for the population?

A) There can be no natural selection.
B) A population must not be very large.
C) There can only be mating between relatives.
D) A population can only have some migration.
E) A population can have only occasional matings.

Question 18

Why is the Hardy-Weinberg principle useful to biologists?

A) It describes most populations.
B) It proves that Mendel was correct for populations.
C) It explains the existence of variation in populations.
D) It explains the existence of a large number of species.
E) It identifies those factors that can change allele or genotype frequencies.

Question 19

Under which mating condition is the Hardy-Weinberg principle applicable?

A) Matings are nonrandom.
B) Matings between individuals are random.
C) Matings between families occur preferentially.
D) Matings between individuals of different genotypes occur preferentially.
E) Matings between individuals of the same genotypes occur preferentially.

Question 20

What best describes all of the alleles for all the loci present in a population?

A) gene pool
B) allele collection
C) population variation
D) evolutionary potential
E) population compilation

Question 21

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

Question 22

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

Question 23

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.

Question 24

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.

Question 25

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

Question 26

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

Question 27

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

Question 28

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

Question 29

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

Question 30

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

Question 31

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

Question 32

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.

Question 33

What is the only source of all new alleles?

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

Question 34

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

Question 35

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.

Question 36

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

Question 37

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.

Question 38

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.

Question 39

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.

Question 40

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.

Question 41

Discuss how two of the following alter allele frequencies in populations: nonrandom mating, genetic drift, gene flow, and natural selection.

Question 42

If environmental conditions continue to favor one specific group of homozygotes over the rest of the population, then ____ selection will eventually occur.

A) stabilizing
B) directional
C) disruptive
D) abnormal
E) frequency-dependent

Question 43

The amount of observable variation due to environment can be measured by comparing the number, frequency and kinds of alleles in both parents and offspring.
_________

Question 44

In ____ selection, individuals with a phenotype near the mean are favored over those at the phenotypic extremes.

A) natural
B) disruptive
C) stabilizing
D) directional
E) frequency-dependent

Question 45

The Hardy-Weinberg principle shows that if the population is large , inheritance alone does not cause changes in allele frequency.
_______

Question 46

Which is defined by the presence of two or more different alleles in a population for a given locus?

A) a gene pool
B) heterozygosity
C) polygenic stasis
D) genetic polymorphism
E) frequency independent selection

Question 47

When phenotypes are favored at one extreme of a normal distribution, ____ selection occurs.

A) stabilizing
B) directional
C) disruptive
D) abnormal
E) frequency-dependent

Question 48

In the human species, a heterozygote advantage is demonstrated by which condition?

A) albinism
B) hemophilia
C) Down syndrome
D) sickle cell anemia
E) Klinefelter syndrome

Question 49

The overuse of antibiotics has led to a form of antibiotic resistant tuberculosis. This has occurred as a result of:

A) directional selection within the bacterial population.
B) stabilizing selection within the bacterial population.
C) disruptive selection within the bacterial population.
D) balanced polymorphism within the bacterial population.
E) a heterozygote advantage within the bacterial population.

Question 50

Figure 19-1 What type of selection is represented by the accompanying figure?

A) no selection
B) natural selection
C) disruptive selection
D) stabilizing selection
E) directional selection

Question 51

Figure 19-1 Refer to the accompanying figure. Which beetle phenotype has the highest probability of survival?

A) 1
B) 2
C) 3
D) 4
E) There is no difference in survival rate.

Question 52

Differentiate between genotype, phenotype, and allele frequencies.

Question 53

Balanced polymorphism can be maintained by the combined actions of:

A) the founder effect and genetic drift.
B) heterozygote advantage and genetic drift.
C) heterozygote advantage and the founder effect.
D) frequency-dependent selection and the founder effect.
E) heterozygote advantage and frequency-dependent selection.

Question 54

Which is the only process that can lead to adaptations and directed genetic change of a population?

A) mutation
B) migration
C) inbreeding
D) genetic drift
E) natural selection

Question 55

Discuss how genetic variability is maintained through genetic polymorphism.

Question 56

Figure 19-2 Based on the data in the accompanying figure, the infant with the highest probability of survival would weigh:

A) 11 lbs.
B) 9 lbs.
C) 7 lbs.
D) 5 lbs.
E) 3 lbs.

Question 57

Extensive data from hospitals have shown that infants born with intermediate weights are the ones most likely to survive. This is a classic example of which type of selection?

A) directional selection
B) stabilizing selection
C) disruptive selection
D) natural selection
E) no selection

Question 58

What is heterozygote advantage? Provide one example of this and briefly explain.

Question 59

List the five conditions that must be met in order to satisfy the predictions of the Hardy-Weinberg principle.

Question 60

Based on the data in the accompanying figure, an infant with 90% survival (or 10% death) would weigh:

A) 11 lbs.
B) 9 lbs.
C) 7 lbs.
D) 5 lbs.
E) 3 lbs.

Question 61

Bacterial populations have been exposed to an antibiotic and have developed resistance to the antibiotic over time. Would this be an example of stabilizing selection, directional selection, or disruptive selection? Explain your reasoning.

Question 62

When a population goes through a bottleneck, genetic drift occurs in the large population of survivors of a severe change in environment.
___________

Question 63

Why is the Hardy-Weinberg principle important, considering that genetic equilibrium seldom occurs in nature?

Question 64

Natural selection acts directly on the genotype of an organism.
_______

Question 65

In nonrandom mating, each individual in a population has an equal chance of mating with any individual of the opposite sex.
_________

Question 66

For a particular gene, the frequency of the dominant allele H is 0.65. The total population size is 10,000 individuals. In addition, the homozygous recessive condition results in living but sterile offspring.
Fill in the table of values for the generations indicated:
Does this population exhibit Hardy-Weinberg equilibrium? Why or why not? If not, what assumptions does the Hardy-Weinberg principle make that appear to be inapplicable in this situation?

Question 67

The allele for sickle cell anemia is maintained in populations by frequency dependent selection .
_______________

Question 68

A type of genetic flow called the founder effect occurs when a small number of individuals from a large population form a new colony.
_________

Question 69

The observation by scientists that flies preferentially mate with those of similar phenotypes illustrates random mating.

Question 70

Human MN blood types illustrate the Hardy Weinberg principle because these blood type antigens are not subject to inheritance.
______________

Question 71

Explain why mutations are almost always neutral or harmful.

Question 72

Non-inbred mice had a consistently lower survival than inbred mice.
__________