chapter 15, Evolution on a small scale Flashcards
1
Q
What is the name of the component of blood that carries oxygen?
A
Hemoglobin
2
Q
How does the body respond to a higher altitude with lower oxygen levels?
A
It produces more hemoglobin
3
Q
What health problems can occur due to increased hemoglobin levels at extreme elevations?
A
Hypertension
4
Q
Which disease affects people who live at high altitudes for extended periods of time?
A
Chronic mountain sickness
5
Q
What is the specific gene allele that reduces hemoglobin production at high elevations in Tibetans?
A
ESPA1
6
Q
When did the EPSA1 gene enter the Tibetan population?
A
40,000 years ago
7
Q
How did the EPSA1 gene most likely enter the Tibetan population?
A
Through interbreeding between Tibetans and Denisovans
8
Q
What is the name of the ancient group of humans that share the EPSA1 gene with Tibetans?
A
Denisovans
9
Q
In what ways does this chapter explore gene pool changes over time?
A
Natural selection and microevolution
10
Q
What component of blood does the individual’s body respond to when a person moves to a higher altitude?
A
oxygen
11
Q
What happens when the amount of hemoglobin is increased substantially?
A
blood thickens and becomes more viscous
12
Q
What is the cause of the increase in blood clots?
A
hypertension
13
Q
Who has the EPSA1 gene found to be similar to?
A
Tibetans
14
Q
The EPSA1 gene in Tibetans is identical to a similar gene found in what group?
A
Denisovans
15
Q
What is the name of a gene that reduces hemoglobin production at high elevations?
A
high-elevation allele
16
Q
When did the EPSA1 gene enter the Tibetan population?
A
40,000 years ago
17
Q
What is the process that results in adaptation of a population to the biotic living and abiotic nonliving components of the environment?
A
Natural selection
18
Q
What do organisms acquire resources through?
A
competition, predation, and parasitism
19
Q
What is the abiotic environment dependent mainly on temperature and precipitation?
A
weather conditions
20
Q
Who first proposed that natural selection was the mechanism by which species evolve and adapt to a changing environment?
A
Charles Darwin
21
Q
What are the two main components of the environment?
A
Biotic and abiotic
22
Q
How do organisms respond to the biotic components of their environment?
A
By acquiring resources through competition, predation, and parasitism
23
Q
What type of selection favors phenotypes that are better adapted to the environment?
A
Directional selection
24
Q
Which type of selection decreases the prevalence of detrimental phenotypes?
A
Stabilizing selection
25
In a population, the frequency distributions of phenotypes often resemble which type of curve?
Bell-shaped curve
26
How many types of natural selection are there? name them.
Three:
Directional selection.
Disruptive selection.
Stabilizing selection.
27
Which type of selection favors extreme phenotypes and leads to the splitting of a population into two distinct groups?
Disruptive selection
28
Natural selection works to decrease the prevalence of which type of phenotypes?
a) Detrimental phenotypes
b) Beneficial phenotypes
c) Neutral phenotypes
d) All types of phenotypes
Detrimental phenotypes
29
Which type of selection favors phenotypes that are closer to the average value of the trait?
a) Stabilizing selection
b) Directional selection
c) Disruptive selection
d) None of the above
Stabilizing selection
30
What type of curve do the frequency distributions of phenotypes in a population often resemble?
a) Bell-shaped curve
b) Straight line
c) Exponential curve
d) None of the above
Bell-shaped curve
31
Which type of selection favors phenotypes that are further away from the average value of the trait?
Disruptive selection
32
Natural selection works to favor phenotypes that are better adapted to which factor?
The environment
33
Which of the following is NOT involved in evolution by natural selection?
a) Variation
b) Inheritance
c) Decreased fitness
d) Increased fitness
Decreased fitness
34
What is the main factor that determines which individuals become more prevalent in a population over time?
Increased fitness
35
What is the role of variation in evolution by natural selection?
It allows for differences among individuals in a population.
36
Which individuals are more likely to reproduce and pass on their genes to the next generation?
a) Individuals with decreased fitness
b) Individuals with increased fitness
c) All individuals in a population have an equal chance of reproducing.
d) The oldest individuals in a population.
b) Individuals with increased fitness
37
What is the main driver of population changes over time?
Increased fitness
38
What is the significance of heritable genetic differences in evolution by natural selection?
They provide the basis for variation among individuals in a population.
39
Which individuals are considered more fit in the context of natural selection?
a) Individuals with decreased fitness
b) Individuals with increased fitness
c) All individuals in a population have an equal level of fitness.
d) The youngest individuals in a population.
Individuals with increased fitness
40
What is the main outcome of natural selection?
The more fit individuals become more prevalent in a population over time.
41
Which factor ensures that genetic traits are passed on from one generation to the next?
a) Variation
b) Inheritance
c) Increased fitness
d) Decreased fitness
Inheritance
42
What is the role of adaptation in natural selection?
It allows individuals to better survive and reproduce in their environment.
43
Stabilizing selection occurs when:
a) Extreme phenotypes are favored
b) Individuals near the average are favored
c) All phenotypes have an equal chance of survival
d) The environment does not play a role in selection
b) Individuals near the average are favored
44
What is the most common form of selection?
a) Directional selection
b) Stabilizing selection
c) Disruptive selection
d) Artificial selection
b) Stabilizing selection
45
In stabilizing selection, extreme phenotypes are:
a) Favored
b) Selected against
c) Equally favored
d) Not affected by selection
b) Selected against
46
Stabilizing selection is characterized by:
a) The selection of extreme phenotypes
b) The selection of average phenotypes
c) Random selection of phenotypes
d) No selection of phenotypes
b) The selection of average phenotypes
47
What is directional selection?
A) When the frequency distribution curve remains unchanged
B) When the frequency distribution curve shifts in a random direction
C) When an extreme phenotype is favored
D) When a population is adapting to a changing environment
E) When a population is not adapting to a changing environment
C) When an extreme phenotype is favored
48
Which example demonstrates directional selection?
A) None of the above
B) Drug-resistant strains of bacteria causing tuberculosis
C) Widespread use of antibiotics and pesticides
D) Populations of bacteria and insects becoming resistant to chemicals
E) People worldwide being threatened by drug-resistant bacteria
D) Populations of bacteria and insects becoming resistant to chemicals
49
How does directional selection affect the frequency distribution curve?
A) It causes the curve to become symmetric
B) It shifts in the opposite direction of the favored phenotype
C) It shifts in the direction of the favored phenotype
D) It remains unchanged
E) It shifts in a random direction
C) It shifts in the direction of the favored phenotype
50
Why does the number of resistant bacteria keep increasing in the presence of antibiotics?
A) Non-resistant bacteria are more likely to pass on their genes
B) Resistant bacteria are genetically superior
C) There is no change in the population of bacteria
D) Antibiotics do not affect bacteria
E) Resistant bacteria are more likely to survive and pass on their genes
E) Resistant bacteria are more likely to survive and pass on their genes
51
What type of selection was observed in the experiment with guppies?
A) Directional selection
B) Sexual selection
C) Disruptive selection
D) Stabilizing selection
A) Directional selection
The experiment with guppies demonstrated directional selection, favoring specific traits in different environments.
52
What favored male guppies in the area below the waterfall?
A. Large and colorful appearance to attract mates
B. Small and drab-colored appearance to avoid detection by pike
C. Aggressive behavior towards other guppies
D. Ability to swim against the current
Small and drab-colored appearance to avoid detection by pike (B)
In the lower area, natural selection favored small and drab-colored male guppies to avoid detection by the pike
53
What caused a change in the phenotype of male guppies in the area above the waterfall?
A. Introduction of a new predator
B. Absence of selection for small and drab-colored traits
C. Genetic mutation
D. Competition with other fish species
Absence of selection for small and drab-colored traits (B)
The absence of selection for small and drab-colored traits caused a change in the phenotype of male guppies in the area above the waterfall.
54
In the experiment with guppies, which area experienced natural selection favoring small and drab-colored male guppies?
A. Both areas experienced the same selection pressure
B. The area above the waterfall without pike
C. The area below the waterfall with pike
D. The area above the waterfall with pike
The area below the waterfall with pike (C)
The environment below the waterfall, stocked with pike, resulted in natural selection favoring small and drab-colored male guppies to avoid detection by the pike.
55
What caused a change in the phenotype of male guppies in the area above the waterfall?
A. Genetic mutation
B. Competition with other fish species
C. Introduction of a new predator
D. Absence of selection pressure
Absence of selection pressure (D)
The absence of selection pressure in the area above the waterfall caused a change in the phenotype of male guppies towards larger, more colorful guppies
56
What was the impact of moving male guppies to the area above the waterfall?
A. Increased predation by pike
B. No change in phenotype
C. Phenotypic change towards smaller, drab-colored guppies
D. Phenotypic change towards larger, more colorful guppies
Phenotypic change towards larger, more colorful guppies (D)
Moving male guppies to the area above the waterfall, where there was an absence of selection pressure, caused a change in the phenotype towards larger, more colorful guppies
57
Disruptive selection favors:
A. Intermediate phenotypes
B. Polymorphism
C. Extreme phenotypes
D. No particular phenotype
C. Extreme phenotypes
Explanation: Disruptive selection occurs when two or more extreme phenotypes are favored over any intermediate phenotype. This leads to the occurrence of different forms, or polymorphism, within a population of the same species.
58
Which environment favors snails with dark shells lacking light bands?
A. Low-vegetation areas
B. Forest areas
C. Both low-vegetation and forest areas
D. Neither low-vegetation nor forest areas
A. Low-vegetation areas
Explanation: In low-vegetation areas, thrushes feed mainly on snails with dark shells that lack light bands.
59
Sexual selection refers to adaptive changes in males and females that lead to:
A. Increased ability to secure food
B. Increased ability to survive in harsh environments
C. Increased ability to secure a mate
D. Increased ability to reproduce asexually
C. Increased ability to secure a mate
Explanation: Sexual selection involves adaptations in males and females that enhance their chances of finding a suitable mate.
60
Males often compete in order to inseminate as many females as possible because:
A. They produce few offspring
B. They continuously produce sperm in great quantity
C They have limited access to mates
D They have limited access to resources
B.They continuously produce sperm in great quantity
Explanation: Males can produce many offspring because they continuously produce sperm in great quantity, which leads them to compete for as many females as possible.
61
The choice of a mate is more crucial for:
A.Males
B.Females
C.It is equally crucial for both males and females
D.It is not crucial for either males or females
B. Females
Explanation: The choice of a mate is usually more crucial for females because they produce fewer eggs and need to ensure the best fitness, or ability to produce surviving offspring.
62
Sexual selection in males usually results in:
A. Increased ability to compete with other males for a mate
B. Increased ability to care for offspring
C. Decreased ability to attract females
D. Decreased ability to compete with other males for a mate
A. Increased ability to compete with other males for a mate
Explanation: Sexual selection in males often leads to adaptations that enhance their ability to compete with other males for a mate.
63
Sexual selection in females favors:
A. Choosing multiple mates
B. Choosing a single male with the best fitness
C. Not choosing any male as a mate
D. Choosing the weakest male as a mate
B.Choosing a single male with the best fitness
Explanation: Sexual selection in females typically favors the choice of a single male with the best fitness, or ability to produce surviving offspring.
64
Why doesn't natural selection always produce perfectly adapted organisms?
A.Because evolution starts from scratch every time
B.Because adaptations are limited by available variations
C.Because organisms do not evolve over time
D.Because natural selection does not exist
B.Because adaptations are limited by available variations
Explanation: Natural selection is constrained by the available variations within a species, and each species must build upon its own evolutionary history, which limits the amount of variation that can be acted upon by natural selection.
65
What happens when the environment changes while adaptations are evolving?
A.Adaptations become more effective
B.Adaptations become less effective
C.Adaptations remain unaffected by environmental changes
D.Adaptations become irrelevant
B.Adaptations become less effective
Explanation: As the environment changes, the effectiveness of certain adaptations may be minimized or reduced.
66
Imperfections in organisms are common because:
A. Evolution starts from scratch every time
B. Organisms do not evolve over time
C. Necessary compromises are made during evolution
D. Organisms are perfectly adapted to their environment
C.Necessary compromises are made during evolution
Explanation: Imperfections in organisms are common because necessary compromises are often made during the evolutionary process.
67
What is one feature that has contributed to human success but also poses a risk of injury?
A.Dexterous hands
B.Flexible spine
C.Strong legs
D.Sharp teeth
A.Dexterous hands
Explanation: The dexterity of human hands has contributed to our success, but the vertebrate spine, which did not originally evolve to stand erect, poses a risk of injury.
68
What is the benefit of evolving a certain feature worth?
A.The cost of the feature
B.Nothing
C.The benefit of other features
D.The cost of other features
A.The cost of the feature
Explanation: The benefit of evolving a certain feature is considered worth the cost associated with it.
69
Which type of selection favors polymorphism within a population?
A.Disruptive selection
B.Stabilizing selection
C.Directional selection
D.Random selection
A.Disruptive selection
Explanation: Disruptive selection favors polymorphism, which refers to the occurrence of different forms within a population.
70
What does sexual selection primarily involve?
A.Choosing mates based on physical appearance only
B.Choosing mates based on genetic compatibility only
C.Competition between males for access to females
D.Competition between females for access to males
C.Competition between males for access to females
Explanation: Sexual selection primarily involves competition between males for access to females.
71
Is sexual selection considered a form of natural selection?
A.Yes
B.No
A.Yes
Explanation: Sexual selection is often considered a form of natural selection as it influences the reproductive success and fitness of individuals within a population.
72
What is the benefit of maintaining variation in a population?
A. It allows populations to adapt to new conditions
B. It increases the chance of extinction
C. It reduces the genetic diversity
D. It prevents natural selection from occurring
A. It allows populations to adapt to new conditions
Explanation: Maintaining variation in a population ensures that there is genetic diversity, which increases the chances of individuals being able to adapt to changing environments.
73
Which of the following forces promote variation in a population?
A. Natural selection
B. Genetic drift
C. Mutation, recombination, and fertilization
D. Gene flow between two populations
C. Mutation, recombination, and fertilization
Explanation: Mutation generates new alleles, recombination and independent assortment shuffle alleles during gametogenesis, and fertilization creates new combinations of alleles from those present in the gene pool.
74
How can gene flow contribute to maintaining variation?
A. By reducing genetic diversity between populations
B. By increasing homozygosity within a population
C. By introducing new alleles into a small homozygous population
D. By preventing natural selection from occurring
C. By introducing new alleles into a small homozygous population
Explanation: Gene flow occurs when individuals migrate between populations, bringing their alleles with them. If a receiving population is small and mostly homozygous, gene flow can be a significant source of new alleles.
75
What is disruptive selection?
A. A type of natural selection that favors certain phenotypes over others.
B. A type of natural selection that promotes polymorphism in a population.
C. A type of genetic drift that reduces genetic diversity.
D. A type of mutation that generates new alleles.
B. A type of natural selection that promotes polymorphism in a population.
Explanation: Disruptive selection favors extreme phenotypes over intermediate ones, leading to the maintenance of polymorphism in a population.
76
How do heterozygotes help maintain variation in diploid species?
A. By conserving recessive alleles in the population
B. By increasing homozygosity within a population
C. By preventing gene flow between two populations
D. By reducing the chances of natural selection occurring
A. By conserving recessive alleles in the population
Explanation: Heterozygotes have one dominant and one recessive allele, which allows them to conserve recessive alleles in the population even if they are not expressed phenotypically.
77
What is balanced polymorphism?
A. The presence of two different alleles of a gene at a certain ratio in a population.
B. The absence of genetic variation within a population.
C. The complete dominance of one allele over another.
D. The occurrence of mutation at a high frequency.
A. The presence of two different alleles of a gene at a certain ratio in a population.
Explanation: Balanced polymorphism refers to the situation when environmental conditions cause natural selection to maintain two different alleles of a gene at a specific ratio within a population.
78
Which genotype is associated with sickle-cell disease?
A. HbHb
B. HbsHbs
C. Hb^HbS
D. HbAHbA
B. HbsHbs
Explanation: Individuals with sickle-cell disease have the genotype HbsHbs, where Hb represents normal hemoglobin and S represents the sickle cell variant.
79
Why do individuals with sickle-cell trait have an advantage?
A. Their red blood cells become sickle-shaped only when oxygen levels are low.
B. They have higher fitness due to increased oxygen-carrying capacity.
C. They are immune to malaria.
D. They have a higher frequency of the recessive allele in regions where malaria is prevalent.
A. Their red blood cells become sickle-shaped only when oxygen levels are low.
Explanation: Individuals with sickle-cell trait have an advantage because their red blood cells usually become sickle-shaped only when the oxygen content of the environment is low, reducing the negative effects of sickling.
80
What have geneticists found about the distribution of sickle-cell disease in Africa?
A. The recessive allele (Hb) has a higher frequency in regions with low malaria prevalence.
B. The dominant allele (HbS) has a higher frequency in regions with high malaria prevalence.
C. The recessive allele (Hb) has a higher frequency in regions with high malaria prevalence.
D. The dominant allele (HbS) has a higher frequency in regions with low malaria prevalence.
C. The recessive allele (Hb) has a higher frequency in regions with high malaria prevalence.
Explanation: Geneticists studying the distribution of sickle-cell disease in Africa have found that the recessive allele (Hb) has a higher frequency in regions where malaria is also prevalent.
81
Which of the following statements is true about natural selection and variation?
A. Natural selection always reduces variation within populations.
B. Natural selection can increase variation within populations.
C. Natural selection does not affect variation within populations.
D. Natural selection only acts on phenotypic traits, not genotypic variation.
B. Natural selection can increase variation within populations.
Explanation: Although natural selection often reduces variation by favoring certain phenotypes, it can also increase variation by promoting polymorphism and maintaining different alleles within populations.
82
Which force promotes genetic diversity by shuffling alleles during gametogenesis?
A. Mutation
B. Recombination
C. Fertilization
D. Gene flow
B. Recombination
Explanation: Recombination, along with independent assortment, shuffles alleles during the formation of gametes, leading to increased genetic diversity within a population.
83
What is the role of gene flow in maintaining variation?
A. It reduces genetic diversity between populations.
B. It increases homozygosity within a population.
C. It introduces new alleles into a population.
D. It prevents natural selection from occurring.
C. It introduces new alleles into a population.
Explanation: Gene flow occurs when individuals migrate between populations, bringing their alleles with them and introducing new genetic variation into the receiving population.
84
How does disruptive selection contribute to maintaining variation?
A. By reducing genetic diversity within a population.
B. By favoring certain phenotypes over others.
C. By preventing gene flow between two populations.
D. By increasing the chances of mutation occurring.
B. By favoring certain phenotypes over others.
Explanation: Disruptive selection favors extreme phenotypes over intermediate ones, promoting polymorphism and maintaining variation within a population.
85
What is the advantage of heterozygotes in maintaining variation?
A. They increase homozygosity within a population.
B. They prevent gene flow between two populations.
C. They conserve recessive alleles in the population.
D. They reduce the chances of natural selection occurring.
C.They conserve recessive alleles in the population.
Explanation: Heterozygotes have one dominant and one recessive allele, allowing them to conserve recessive alleles in the population even if they are not phenotypically expressed.
86
Distinguish between directional, stabilizing, and disruptive selection.
Directional selection favors one extreme phenotype. Stabilizing selection favors the intermediate phenotype. Disruptive selection favors two or more extreme phenotypes over any intermediate phenotype.
87
Explain how sexual selection represents a form of natural selection.
In females, sexual selection favors the fittest males, meaning those that have the traits that improve the ability to reproduce. By selecting the fittest male, the female is improving the chances that her traits will be passed on to her offspring.
88
When were biologists able to apply the principles of genetics to populations?
the 1930s
89
What do you use to calculate the allele frequencies in the population?
the allele frequencies in the population
90
What causes changes in gene pool frequencies?
natural selection
91
What caused changes in gene pool frequencies?
Microevolution
92
Which of the following best describes the concept of evolution?
a) Changes in an individual's traits over its lifetime
b) Genetic changes in a population over time
c) Development of new skills and abilities in individuals
d) Changes in the environment causing temporary alterations in traits
b) Genetic changes in a population over time
93
What is the main difference between microevolution and changes in an individual's traits?
a) Microevolution occurs over many generations, while changes in traits occur over an individual's lifetime
b) Microevolution is driven by environmental factors, while changes in traits are genetic
c) Microevolution affects only certain traits, while changes in traits can be widespread
d) Microevolution can be observed in a single individual, while changes in traits are observed in a population
a) Microevolution occurs over many generations, while changes in traits occur over an individual's lifetime
94
In population genetics, what does the gene pool of a population consist of?
a) The total number of genes in the population
b) The various alleles at all the gene loci in all individuals
c) The combination of dominant and recessive traits in the population
d) The genetic material passed on from one generation to the next
b) The various alleles at all the gene loci in all individuals
95
What is the primary factor that leads to changes in gene pool frequencies in a population?
a) Random mating and genetic recombination
b) Environmental changes and natural selection
c) Dominant allele increase through sexual reproduction
d) The development of new traits in individuals
a) Random mating and genetic recombination
96
According to the information provided, what is the main mechanism responsible for bringing about changes in gene pool frequencies in a population?
a) Mutation and genetic drift
b) Natural selection and environmental pressures
c) Sexual reproduction and genetic recombination
d) Changes in individual traits over time
c) Sexual reproduction and genetic recombination
97
According to the Hardy-Weinberg principle, the equilibrium of genotype frequencies in a gene pool may be represented by the equation:
A) p2 + 2pq + q2 = 0
B) p2 + 2pq + q2 = 1
C) p2 - 2pq + q2 = 1
D) p2 - 2pq + q2 = 0
B) p2 + 2pq + q2 = 1
98
In the example of peppered moths, the dark allele (D) was present in 20% of the population. What is the frequency of the recessive allele (d) in the gene pool?
A) 0.20
B) 0.80
C) 0.04
D) 0.64
B) 0.80
99
Which of the following conditions is required for the mathematical relationships of the Hardy-Weinberg principle to remain in effect in each succeeding generation of a sexually reproducing population?
A) High gene flow
B) Nonrandom mating
C) Small population size
D) No genetic drift
D) No genetic drift
100
Industrial melanism, the increase in the frequency of a dark moth phenotype due to pollution, provides an example of:
A) Genetic drift
B) Natural selection
C) Gene flow
D) Mutation
B) Natural selection
101
Which of the following factors can cause a divergence from the Hardy-Weinberg equilibrium?
A) Random mating
B) Genetic mutation
C) No gene flow
D) Large population size
B) Genetic mutation
102
What is the raw material for evolutionary change according to the provided content?
A) Gene flow
B) Genetic drift
C) Mutations
D) Random mating
C) Mutations
103
Which of the following is true about mutations in sexually reproducing organisms?
A) Mutations immediately affect the phenotype
B) Mutations do not introduce variations among members of a population
C) Mutations are not dependent on the environment
D) Mutations, if recessive, do not immediately affect the phenotype
D) Mutations, if recessive, do not immediately affect the phenotype
104
The Hardy-Weinberg principle states that an equilibrium of genotype frequencies exists in a gene pool. What are the conditions that can cause a divergence from this equilibrium?
A) Random mating and natural selection
B) Genetic drift and gene flow
C) No mutations and small population size
D) Nonrandom mating and natural selection
B) Genetic drift and gene flow
105
What is the frequency of the dominant allele (in the case of the moths, the D allele) if the recessive allele frequency is 0.80?
A) 0.20
B) 0.80
C) 0.04
D) 0.64
A) 0.20
106
Which of the following conditions is required for the mathematical relationships of the Hardy-Weinberg principle to remain in effect in each succeeding generation of a sexually reproducing population?
A) High gene flow
B) Nonrandom mating
C) Small population size
D) No mutations
D) No mutations
107
In the context of genetic drift, which of the following populations is more likely to experience a sampling error?
a) A population with 1,000 individuals
b) A population with 100 individuals
c) A population with 10,000 individuals
d) A population with 500 individuals
b) A population with 100 individuals
108
How does gene flow impact the possibility of speciation?
a) Gene flow promotes speciation by increasing allele frequency differences among populations.
b) Gene flow prevents speciation by making gene pools similar and reducing allele frequency differences among populations.
c) Gene flow has no impact on the possibility of speciation.
d) Gene flow promotes speciation by introducing novel alleles that lead to distinct populations.
b) Gene flow prevents speciation by making gene pools similar and reducing allele frequency differences among populations.
109
What is the impact of inbreeding on allele frequencies in a population?
a) Inbreeding increases allele frequencies.
b) Inbreeding decreases allele frequencies.
c) Inbreeding does not change allele frequencies.
d) Inbreeding leads to the loss of alleles in a population.
c) Inbreeding does not change allele frequencies.
110
What is the main factor that determines the adaptive value of a mutation in a changing environment?
a) The mutation's impact on genetic drift
b) The mutation's effect on gene flow
c) The mutation's phenotypic difference in the new environment
d) The mutation's influence on assortative mating
c) The mutation's phenotypic difference in the new environment
111
Which mating pattern is most likely to cause the population to subdivide into two phenotypic classes?
a) Random mating
b) Assortative mating
c) Inbreeding
d) Sexual selection
b) Assortative mating
112
How does genetic drift lead to changes in allele frequencies in a small population?
a) Genetic drift reduces the occurrence of mutations.
b) Genetic drift increases the number of heterozygotes.
c) Genetic drift leads to the loss of alleles, causing other alleles to become fixed in the population.
d) Genetic drift promotes the spread of advantageous mutations.
c) Genetic drift leads to the loss of alleles, causing other alleles to become fixed in the population.
113
What was the main factor contributing to the change in allele frequencies in the Drosophila populations in the experiment?
a) Gene flow
b) Random mating
c) Assortative mating
d) Genetic drift
d) Genetic drift
114
How does sexual selection impact mating patterns?
a) Sexual selection promotes random mating.
b) Sexual selection favors characteristics that lead to nonrandom mating.
c) Sexual selection has no impact on mating patterns.
d) Sexual selection reduces gene flow between populations.
b) Sexual selection favors characteristics that lead to nonrandom mating.
115
What is the primary impact of gene flow on allele frequencies within populations?
a) Gene flow increases allele frequencies.
b) Gene flow decreases allele frequencies.
c) Gene flow introduces novel alleles, increasing variation within populations.
d) Gene flow leads to the loss of alleles.
c) Gene flow introduces novel alleles, increasing variation within populations.
116
In the context of genetic drift, which population is more likely to experience changes in allele frequencies due to chance events?
a) A population with a high rate of gene flow
b) A large population
c) A small population
d) A population with high genetic diversity
c) A small population
117
In the context of genetic drift, which of the following populations is more likely to experience a sampling error?
a) A population with 1,000 individuals
b) A population with 100 individuals
c) A population with 10,000 individuals
d) A population with 500 individuals
b) A population with 100 individuals
118
How does gene flow impact the possibility of speciation?
a) Gene flow promotes speciation by increasing allele frequency differences among populations.
b) Gene flow prevents speciation by making gene pools similar and reducing allele frequency differences among populations.
c) Gene flow has no impact on the possibility of speciation.
d) Gene flow promotes speciation by introducing novel alleles that lead to distinct populations.
b) Gene flow prevents speciation by making gene pools similar and reducing allele frequency differences among populations.
119
What is the impact of inbreeding on allele frequencies in a population?
a) Inbreeding increases allele frequencies.
b) Inbreeding decreases allele frequencies.
c) Inbreeding does not change allele frequencies.
d) Inbreeding leads to the loss of alleles in a population.
c) Inbreeding does not change allele frequencies.
120
What is the main factor that determines the adaptive value of a mutation in a changing environment?
a) The mutation's impact on genetic drift
b) The mutation's effect on gene flow
c) The mutation's phenotypic difference in the new environment
d) The mutation's influence on assortative mating
c) The mutation's phenotypic difference in the new environment
121
Which mating pattern is most likely to cause the population to subdivide into two phenotypic classes?
a) Random mating
b) Assortative mating
c) Inbreeding
d) Sexual selection
b) Assortative mating
122
How does genetic drift lead to changes in allele frequencies in a small population?
a) Genetic drift reduces the occurrence of mutations.
b) Genetic drift increases the number of heterozygotes.
c) Genetic drift leads to the loss of alleles, causing other alleles to become fixed in the population.
d) Genetic drift promotes the spread of advantageous mutations.
c) Genetic drift leads to the loss of alleles, causing other alleles to become fixed in the population.
123
What was the main factor contributing to the change in allele frequencies in the Drosophila populations in the experiment?
a) Gene flow
b) Random mating
c) Assortative mating
d) Genetic drift
d) Genetic drift
124
How does sexual selection impact mating patterns?
a) Sexual selection promotes random mating.
b) Sexual selection favors characteristics that lead to nonrandom mating.
c) Sexual selection has no impact on mating patterns.
d) Sexual selection reduces gene flow between populations.
b) Sexual selection favors characteristics that lead to nonrandom mating.
125
What is the primary impact of gene flow on allele frequencies within populations?
a) Gene flow increases allele frequencies.
b) Gene flow decreases allele frequencies.
c) Gene flow introduces novel alleles, increasing variation within populations.
d) Gene flow leads to the loss of alleles.
c) Gene flow introduces novel alleles, increasing variation within populations.
126
In the context of genetic drift, which population is more likely to experience changes in allele frequencies due to chance events?
a) A population with a high rate of gene flow
b) A large population
c) A small population
d) A population with high genetic diversity
c) A small population
127
Which of the following is NOT a mechanism of genetic drift?
A) Bottleneck effect
B) Founder effect
C) Natural selection
D) Extreme genetic similarity
C) Natural selection
128
What is the main cause of genetic variation among the cypress groves in California?
A) Environmental conditions
B) Genetic drift
C) Natural selection
D) Human intervention
B) Genetic drift
129
What event can lead to the bottleneck effect?
A) Overharvesting and habitat loss
B) Natural selection
C) Founder effect
D) Extreme genetic similarity
A) Overharvesting and habitat loss
130
What is the main reason for the extreme genetic similarity found in cheetahs?
A) Natural selection
B) Founder effect
C) Bottleneck effect
D) Environmental conditions
C) Bottleneck effect
131
Which population shows a higher frequency of a recessive allele causing an unusual form of dwarfism and polydactylism?
A) Amish of Lancaster County, Pennsylvania
B) German settlers
C) Cheetahs
D) California cypress groves
A) Amish of Lancaster County, Pennsylvania
132
Define the term gene pool and explain how it relates to allele frequencies in a population.
The various alleles at all the gene loci in all individuals make up the gene pool of the population. The gene pool of a population is described in terms of allele frequencies.
133
Explain the Hardy-Weinberg principle. What happens to the equilibrium of allele frequencies when microevolution occurs?
The Hardy-Weinberg principle states that the equilibrium of genotype frequencies in a gene pool will remain stable in each succeeding generation of a sexually reproducing population as long as five conditions are met. Microevolution can be detected and measured by noting the amount of deviation from Hardy-Weinberg equilibrium that is exhibited by the genotype frequencies in a population.
134
List the five factors that prevent microevolution in a population.
To prevent microevolution in a population, no mutations must occur, there is no gene flow, only random mating happens, there is no genetic drift, and no natural selection functions.
135
Describe the significance of mutations in terms of evolution.
Mutations are ultimately responsible for all the genetic variability on which evolution depends.
136
Explain how gene flow and nonrandom mating cause microevolution.
Gene flow is the migration of alleles into or out of populations, changing their frequency and leading to microevolution. Nonrandom mating pairs individuals according to their phenotypes and ultimately their genotypes. Inbreeding increases the proportion of homozygotes in the population, and assortative mating causes the population to subdivide into phenotypes. Nonrandom mating can therefore result in microevolution.
137
Describe the consequences of genetic drift and explain why it is more likely to happen in a small population.
With genetic drift, allele frequencies in a gene pool change gradually over time due to chance. In a small population, the probability that an individual with a rare genotype might pass alleles to the next generation is greater. It will be more likely that a decrease or increase in the frequency of this genotype will result.
