Deck 19: Evolutionary Change in Populations

Question 1

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

Answer 1

D

Question 2

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

Answer 2

C

Question 3

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

Answer 3

B

Question 4

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.

Question 5

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 6

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 7

The Hardy-Weinberg principle:

A) states that allele and genotype frequencies change from generation to generation in a population at genetic equilibrium.
B) shows that if the population is large, the process of inheritance by itself causes changes in allele frequencies.
C) allows biologists to calculate allele frequencies in a given population if we know the genotype frequencies, and vice versa.
D) represents an ideal situation that seldom does not occur in the natural world.
E) is not essential to understanding the mechanisms of evolutionary change in sexually reproducing populations.

Question 8

If an environment changes over time, _______________ may favor phenotypes at one of the extremes of the normal distribution.

A) frequency-dependent selection
B) balanced polymorphism
C) directional selection
D) stabilizing selection
E) genetic polymorphism

Question 9

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 10

What is the raw material for evolutionary change because it provides the diversity on which natural selection acts?

A) Frequency-dependent selection
B) Genetic variation
C) Gene flow
D) Genetic polymorphism
E) Stabilizing selection

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

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 13

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 14

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 15

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 16

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

A) Gene pool
B) Allele collection
C) Population variation
D) Evolutionary potential
E) Population compilation

Question 17

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

Question 18

Which of the following is known as the process of natural selection associated with a population well adapted to its environment?

A) Frequency-dependent selection
B) Balanced polymorphism
C) Directional selection
D) Stabilizing selection
E) Genetic polymorphism

Question 19

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 20

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 21

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 22

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 nonharmful alleles.

Question 23

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 24

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 25

In cases of_____________________, the fitness of a particular phenotype depends on how frequently it appears in the population.

A) frequency-dependent selection
B) genetic variation
C) gene flow
D) genetic polymorphism
E) stabilizing selection

Question 26

Negative 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 27

Variation that does not alter the ability of an individual to survive and reproduce, and therefore not an adaptive variation, is called:

A) frequency-dependent selection
B) genetic variation
C) gene flow
D) genetic polymorphism
E) neutral variation

Question 28

___________is the mechanism of evolution first proposed by Darwin.

A) mutation.
B) genetic drift.
C) natural selection.
D) neutral variation.
E) geographic variation.

Question 29

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 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 mechanism results in changes in allele frequencies in a population from one generation to another due to random sampling?

A) Gene flow
B) Mutation
C) Genetic drift
D) Natural selection
E) Disruptive selection

Question 32

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 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

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 35

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 36

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 37

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 38

_____________________ is a special type of directional selection in which there is a trend in several directions rather than just one.

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

Question 39

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 40

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 41

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

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

Question 42

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 43

__________________ selection often acts to maintain genetic variation in populations of prey species.

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

Question 44

The genetic drift that results when a small number of individuals from a large population found a new colony is called the _______________________.

A) the founder effect
B) genetic drift.
C) heterozygote advantage
D) stabilizing selection
E) disruptive selection.

Question 45

Differentiate between genotype frequency, phenotype frequency, and allele frequency.

Question 46

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 47

Variation is introduced into a population through _________________, which is an unpredictable change in deoxyribonucleic acid.

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

Question 48

Why would the population of royal families (of England as well as other countries) not qualify for the Hardy-Weinberg principle?

Question 49

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

Question 50

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

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

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 53

Discuss how genetic variability is maintained through genetic polymorphism.

Question 54

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 55

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 56

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 57

____________________ and frequency-dependent selection are mechanisms that preserve balanced polymorphism.

A) the founder effect
B) genetic drift.
C) heterozygote advantage
D) stabilizing selection
E) disruptive selection.

Question 58

Figure 19-2

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

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

Question 59

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 60

Describe how the following concepts alter allele frequencies in populations: genetic drift and gene flow.

Question 61

Explain why the usefulness of a mutation may vary depending on an organism's environment.

Question 62

If each genotype corresponds to a specific phenotype, the phenotype and genotype frequencies are not the same.

Question 63

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

Question 64

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 65

Natural selection does not act directly on an organism's genotype.

Question 66

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

Question 67

Briefly discuss why the Hardy-Weinberg principle is important. Does genetic equilibrium usually occur in nature? How does this affect the usefulness of the Hardy-Weinberg principle?

Question 68

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

Question 69

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 70

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

Question 71

Bacterial populations have been exposed to an antibiotic and have developed resistance to the antibiotic over time. Briefly explain how this is an example of one of the following: stabilizing selection, directional selection, or disruptive selection? Explain your reasoning.

Question 72

A phenotype frequency is the proportion of a particular phenotype in the population.