Deck 19: Evolutionary Change in Populations

Question 1

In the Hardy-Weinberg equation, the term q² refers to the frequency of:

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

Answer 1

B

Question 2

All of the individuals of the same species that inhabit the same place at the same time are known as:

A) a gene pool.
B) an ecosystem.
C) a community.
D) a population.
E) a genome.

Answer 2

D

Question 3

If a population of 1000 individuals has 160 aa genotypes, 320 Aa genotypes, and 520 AA genotypes, the allele frequency of the dominant allele (A) is:

A) 0.16
B) 0.42.
C) 0.52.
D) 0.68.
E) 0.89.

Answer 3

D

Question 4

The study of the genetic variability within a population and the forces that change allele frequencies is:

A) variation ecology.
B) evolutionary genetics.
C) population genetics.
D) cytogenetics.
E) allele genetics.

Question 5

The Hardy-Weinberg principle is useful because:

A) it explains the existence of variation in populations.
B) it proves that Mendel was correct for populations.
C) it describes most 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 6

In a certain population, 40 of every 1,000 births results in an individual that suffers from cystic fibrosis.What is the allele frequency for the recessive allele that causes cystic fibrosis?

A) 0.004
B) 0.02
C) 0.2
D) 0.4
E) 0.8

Question 7

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

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

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?

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

Question 9

Which of the following best describes a group of Rana pipens living in a pond during the spring months?

A) a community
B) an ecosystem
C) a habitat
D) a population
E) a niche

Question 10

If a population of 1000 individuals has 160 aa genotypes, assuming simple dominance by the A allele, the phenotype frequency of the dominant phenotype is:

A) 0.08.
B) 0.16.
C) 0.42.
D) 0.84.
E) 1.0

Question 11

A population in which the allele and genotype frequencies do not change over time is said to be in:

A) genetic stasis.
B) genetic equilibrium.
C) population stability.
D) allelic disequilibrium
E) allelic balance.

Question 12

If an animal population is diploid, 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 complete set of alleles found in each chromosome.
E) a partial set of alleles found in each cell.

Question 13

If a population of 1000 individuals has 160 aa genotypes, the genotype frequency of the aa genotype is:

A) 0.016.
B) 0.08.
C) 0.16.
D) 0.8.
E) 1.0.

Question 14

The Hardy-Weinberg principle does not assume:

A) no net mutations occur in a population.
B) a large population size.
C) artificial selection is occurring.
D) random mating is occurring.
E) no gene flow is occurring.

Question 15

All of the alleles for all the loci present in a population is called the:

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

Question 16

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) genetic equilibrium.
C) random mating.
D) an increase in non-harmful alleles.
E) genetic polymorphism.

Question 17

A long established population that has had no new individuals entering the population would be considered to be in:

A) genetic stasis.
B) genetic equilibrium.
C) population stability.
D) allelic disequilibrium
E) allele balance.

Question 18

The Hardy-Weinberg principle of genetic equilibrium tells us what to expect when a sexually reproducing population is:

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

Question 19

If all of the alleles of a given locus are the same in a population, then the frequency of that allele is assigned a value of:

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

Question 20

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

A) p² + 2pq² + q² + q² = 100
B) p² + 2p + 2q + q² = 1
C) p² - 2pq + q² = 1
D) 2p² + 2pq + 2q² = 1000
E) p² + 2pq + q² = 1

Question 21

A commonly cited example of genetic drift has occurred within:

A) the cheetah population.
B) the parasite that causes malaria.
C) scale-eating fish.
D) humans, as evidence by birth weight.
E) insects called water boatmen.

Question 22

With inbreeding, one would expect to see an increase in __________ within the population.

A) genetic drift
B) migration
C) heterozygosity
D) homozygosity
E) assortative mating

Question 23

Random evolutionary changes in a small breeding population is known as:

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

Question 24

The Hardy-Weinberg principle is applicable provided:

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

Question 25

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 26

You might expect to see an example of the founder effect in:

A) the Hawaiian Islands.
B) Central Africa.
C) states along the Mississippi River.
D) a tropical rain forest.
E) China.

Question 27

The Hardy-Weinberg principle is applicable provided:

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

Question 28

Positive assortative mating in a population will:

A) produces more mutations each generation.
B) causes natural selection.
C) changes allele frequencies.
D) stabilizes genotype frequencies.
E) increases homozygosity.

Question 29

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 30

Due to a rapid change in the environment, a population of ants was reduced from 1 million to 1 thousand.What type of genetic drift will occur in the gene pool of this population when it expands again?

A) the founder effect
B) migration
C) a genetic bottleneck
D) gene flow
E) natural selection

Question 31

The movement of 25-year-old fertile individuals between Mexico and Canada will eventually contribute to:

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

Question 32

The migration of breeding individuals between populations causes a corresponding movement of alleles, which is referred to as:

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

Question 33

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 34

The only source of all new alleles is:

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

Question 35

Which of the following statements is not true about natural selection?

A) Offspring of individuals that are better adapted will make up a larger proportion of the next generation.
B) Natural selection directs evolution by preserving traits acquired during an individual's lifetime.
C) Natural selection depends on the genetic variability in a population, which arises through mutations.
D) Natural selection acts to preserve favorable traits and eliminate unfavorable traits.
E) Natural selection leads to adaptive evolutionary change.

Question 36

__________ is thought to be due to increased homozygosity.

A) The founder effect
B) Genetic drift
C) Inbreeding depression
D) Heterozygote advantage
E) Gene flow

Question 37

The process that decreases the number of organisms with phenotypes less fit to meet environmental challenges is:

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

Question 38

Which of the following does NOT cause changes in allele frequencies?

A) genetic drift
B) mutation
C) natural selection
D) gene flow from migration
E) random mating

Question 39

Mutations that are not passed on from one generation to the next:

A) result from disruptive selection.
B) are balanced polymorphisms.
C) arise in somatic cells.
D) result from the founder effect.
E) result from genetic drift.

Question 40

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

A) have only moderate migration in and out of the population.
B) have no natural selection.
C) have only occasional matings determined by humans.
D) have mating between relatives.
E) not be very large.

Question 41

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) frequency-dependent
E) abnormal

Question 42

Seriously abnormal phenotypes or harmful mutations are acted against or reduced to low frequencies by:

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

Question 43

Which of the following can produce a population of individuals with a relatively high frequency of a deleterious allele?

A) natural selection
B) mutation
C) migration between large populations
D) the founder effect
E) artificial selection

Question 44

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

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

Question 45

Mutations that may confer no apparent selective advantage in a particular environment are referred to as:

A) natural mutations.
B) equilibrium mutations.
C) selective variations.
D) variable mutations.
E) neutral variations.

Question 46

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) homozygous recessive
B) homozygous dominant
C) heterozygous
D) both heterozygous and homozygous dominant
E) both homozygous dominant and homozygous recessive

Question 47

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) a heterozygote advantage within the bacterial population.
E) balanced polymorphism within the bacterial population.

Question 48

In nature, genes with the potential to produce serious defects are acted against and kept at a low frequency by:

A) neutral variations.
B) stabilizing selection.
C) disruptive selection.
D) frequency dependent selection.
E) natural selection.

Question 49

The presence of two or more different alleles in a population for a given locus is termed:

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

Question 50

When heterozygotes are favored over homozygotes __________ selection occurs.

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

Question 51

Frequency-dependent selection acts to decrease the frequency of which phenotype in a population?

A) the least common phenotype
B) the phenotype at an extreme of the normal distribution
C) the most conspicuous phenotype
D) the most common phenotype
E) the most camouflaged phenotype

Question 52

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) heterozygote advantage and frequency-dependent selection.
E) frequency-dependent selection and the founder effect.

Question 53

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

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

Question 54

Figure 19-5
Use the figure to answer the corresponding question(s).
The differential survival rates associated with birth weights in Figure 19-5 illustrate:

A) balanced polymorphism.
B) genetic drift.
C) neutral variation.
D) stabilizing selection.
E) disruptive selection.

Question 55

Figure 19-5
Use the figure to answer the corresponding question(s).
The distribution of phenotypes for human birth weight is a good example of:

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

Question 56

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

Question 57

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

Question 58

The only process that can lead to adaptations and directed genetic change of a population is:

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

Question 59

Discuss how genetic variability is maintained through genetic polymorphism.

Question 60

Variation that does not alter the ability to survive and reproduce:

A) is not possible with natural selection.
B) reduces genetic polymorphism.
C) is only possible for polygenic traits.
D) is not part of the gene pool.
E) is called neutral variation.

Question 61

MATCHING
Match the evolution vocabulary definition
a.microevolutiom
d.cline
b.fitness
e.balanced polymorphisms
c.natural selection
two or more alleles persist in a population

Question 62

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

Question 63

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

Question 64

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

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

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

Question 67

MATCHING
Match the evolution vocabulary definition
a.microevolutiom
d.cline
b.fitness
e.balanced polymorphisms
c.natural selection
gradual change in a species phenotype and genotype frequencies through a series of geographic populations as result of an environmental gradient

Question 68

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

Question 69

MATCHING
Match the evolution vocabulary definition
a.microevolutiom
d.cline
b.fitness
e.balanced polymorphisms
c.natural selection
average number of surviving organisms of one genotype compared to competing genotypes

Question 70

MATCHING
Match the evolution vocabulary definition
a.microevolutiom
d.cline
b.fitness
e.balanced polymorphisms
c.natural selection
adapts populations organisms to a different type of environment

Question 71

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

Question 72

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 73

MATCHING
Match the evolution vocabulary definition
a.microevolutiom
d.cline
b.fitness
e.balanced polymorphisms
c.natural selection
generation to generation change in allele for genotype frequency

Question 74

For a particular gene, the frequency of the dominant allele H is 0.65.The total population size is 10,000 individuals.Also, the homozygous recessive condition results in living but sterile offspring.
Fill in the table of values for the generations indicated:
Generation
p
q
p²
2pq
q²
1
2
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 75

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

Question 76

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 77

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

Question 78

MATCHING
Match the evolution vocabulary definition
a.microevolutiom
d.cline
b.fitness
e.balanced polymorphisms
c.natural selection
Why is the Hardy-Weinberg principle important, since genetic equilibrium seldom occurs in nature?

Question 79

Explain why mutations are almost always neutral or harmful.