Exam 1 Questions Flashcards

1
Q

Why did Darwin devote so much of his time to pigeons?

  • Darwin was hoping to understand how allelic crosses combined to make complex phenotypes in the offspring.
  • He wanted to develop credible expertise at artificial reproduction.
  • Pigeons were an example of a new species, and Darwin was trying to figure out how new species were formed.
  • He knew that breeders had figured out how hereditary information was passed between parents and offspring.
  • He was hoping to understand how hereditary information was passed between parents and offspring, and explore the power of artificial selection to shape species.
A

He was hoping to understand how hereditary information was passed between parents and offspring, and explore the power of artificial selection to shape species.

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2
Q

Which of the following is not a requirement for natural selection to act to change allele frequencies in a population:

  • That the population mates at random.
  • That within-population genetic variation is present.
  • That this variation is heritable.
  • That there is variance in reproductive success.
  • That reproductive success is dependent in some way on the genetic variation.
A

That the population mates at random.

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3
Q

During the voyage of the Beagle, Darwin visited both the Cape de Verde islands and the Galapagos islands. Why were these visits so important to the development of his theory of evolution? Select THE BEST answer.

  • Darwin was struck by the diversity of finches on the Cape de Verde islands, which demonstrated that adaptation to local habitats could occur.
  • The islands were formed via marine subduction, which proved Lyell’s theory of uniformitarianism and suggested that the earth was older than 6000 years.
  • The islands had nearly identical habitat and climate, but the species on each island resembled those on the nearby continents, rather than each other. This provided evidence against special creation.
  • The marine iguanas of the Galapagos islands demonstrated that species could acquire novel traits.
A

The islands had nearly identical habitat and climate, but the species on each island resembled those on the nearby continents, rather than each other. This provided evidence against special creation.

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4
Q

Jean Léopold Nicolas Frédéric aka ‘Georges’ Cuvier was extremely influential prior to Darwin’s work. How would Cuvier have explained extinction?

  • Species were wiped off the face of the earth during the last ice age in an attempt by the creator to wipe the slate clean.
  • Extinction was caused by the failure of certain species to compete for resources due to an inability to adapt.
  • Fossil animals were placed by the devil to mislead Christians, so extinct animals were essentially fakes and never existed on the planet.
  • Entire species were destroyed by cataclysmic events such as Noah’s flood that were caused by God. Cuvier’s explanation was essentially that God caused extinction.
A

Entire species were destroyed by cataclysmic events such as Noah’s flood that were caused by God. Cuvier’s explanation was essentially that God caused extinction.

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5
Q

Identify the best definition for the term scientific theory

  • A hunch based on careful observation of nature that help to guide a scientist’s work.
  • Theories are overarching explanations that make sense of some aspect of nature, are based on evidence, allow scientists to make valid predictions, and have been tested in many ways.
  • The result of long hours of careful observation and typically a surplus of caffeine.
  • Educated guesses that are based on measurably evidence and that can be tested in indirect ways.
  • A set of predictions and corollaries that have a central unifying theme and that can be tested using qualitative inference.
A

Theories are overarching explanations that make sense of some aspect of nature, are based on evidence, allow scientists to make valid predictions, and have been tested in many ways.

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6
Q

Charles Darwin married his cousin Emma Wedgewood. Why wasn’t he worried about inbreeding depression?

  • Darwin was slightly nervous about his performance and didn’t expect any children to result from his marriage.
  • In truth, he was a little worried about inbreeding depression, but his cousin was very attractive – and wealthy!
  • Darwin knew that he was adopted by Richard Darwin since his father was sterile due to an unfortunate accident with overly tight breeches.
  • Darwin knew very little about genetics and nothing about the loss of heterozygosity and the exposure of deleterious recessive alleles that is caused by inbreeding.
A

Darwin knew very little about genetics and nothing about the loss of heterozygosity and the exposure of deleterious recessive alleles that is caused by inbreeding.

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7
Q

According to Charles Lyell, what was the approximate age of the Earth?

  • No older than 10,000 years, based on his estimates from pollen core samples of Scottish peat bogs.
  • Approximately 6000 years, which was calculated by adding up the generation in the Old Testament of the Bible.
  • At least 4.5 billion years old, give or take the error margin on radiometric dating.
  • Hundreds of thousands of years, or much older than implied by the timeline presented in Genesis.
A

Hundreds of thousands of years, or much older than implied by the timeline presented in Genesis.

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8
Q

Identify the word that matches this definition: empirical evidence interpreted through logic - based on premise that our senses, and extensions of our senses through the use of instruments, provides accurate information about the physical universe

  • naturalism
  • exaptationism
  • methodological naturalism
  • materialism
  • determinism
A

methodological naturalism

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9
Q

Darwin’s theory of evolution provided explanations for all of the following EXCEPT

  • the similarities and differences among species.
  • why Earth is not the center of the universe.
  • the diversity of life on the planet.
  • why the vast majority of species are extinct.
A

why Earth is not the center of the universe.

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10
Q

Which of the following examples best illustrates the concept of spontaneous generation?

  • Maggots spontaneously transform in to flies.
  • Some sea anemones spontaneously bud newly developed young from their outer skin.
  • During flooding, frogs spontaneously arise from mud.
  • When a dried bean is moistened and kept moist, it spontaneously transforms into a bean sprout.
A

During flooding, frogs spontaneously arise from mud.

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11
Q

Rather than rely on creation myths to explain the natural world, early Greek philosophers were among the first to

  • quantify the inheritance of genetic traits through sexual reproduction.
  • develop a philosophy of a natural world driven by physical laws used to explain the world around them.
  • describe the heavenly bodies as gods or personages.
  • understand that our planet is much, much older than previously determined.
A

develop a philosophy of a natural world driven by physical laws used to explain the world around them.

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12
Q

Mathematical models are useful for

  • manipulating experimental conditions in the laboratory.
  • helping us understand how complicated systems work.
  • providing observations of the natural world.
  • disproving the theory of evolution by natural selection.
A

helping us understand how complicated systems work.

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13
Q

Which scientist of those listed below was a contemporary of Charles Darwin and also developed a complete theory of evolution by natural selection?

  • Alfred Russel Wallace
  • Jean-Baptiste Lamarck
  • William Paley
  • Aristotle
A

Alfred Russel Wallace

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14
Q

Darwin realized that the often exquisite fit of species to their environment is primarily the result of

  • paradigm shifts.
  • supernatural events.
  • empirical research.
  • natural selection.
A

natural selection.

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15
Q

If the genotype frequency of a homozygous recessive genotype is equal to 0.023 and a selection coefficient roughly 10% worse than the other genotypes (i.e., s = 0.1), what would we expect its frequency to be after natural selection?

  • It is impossible to answer given the information provided.
  • 0.015
  • 0.0023
  • 0.0207
A

0.0207

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16
Q

In a sample of 1000 diploid individuals, 160 are observed to be homozygous recessive at the ‘A’ locus. Assuming that this is a two-allele system, how many heterozygous individuals should we observe if the population is in HWE?

  • 360
  • It is impossible to calculate given the information provided.
  • 480
  • 840
A

480

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17
Q

Which of the following is the best description of how Hardy Weinberg Equilibrium (HWE) is used as a null model in evolutionary genetics?

  • HWE makes a prediction about the genotype frequencies that we expect to observe in a population in the absence of evolutionary change. By comparing observed genotype frequencies to the expected genotype frequencies, populations that violate the model can be identified.
  • HWE makes a prediction about the genotype frequencies that we expect to observe in a population given a set of assumptions. By comparing expected genotype frequencies to the null distribution, we can infer whether natural selection has occurred.
  • HWE makes predictions about an ideal system that doesn’t experience genetic drift. By measuring the discrepancy between the model and the actual data, we can estimate how much drift has occurred and calibrate the results.
    *
A

HWE makes a prediction about the genotype frequencies that we expect to observe in a population in the absence of evolutionary change. By comparing observed genotype frequencies to the expected genotype frequencies, populations that violate the model can be identified.

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18
Q

Natural selection acts on _______ differences in a population.

  • both genotypic and phenotypic
  • genotypic, not phenotypic
  • phenotypic, not genotypic
  • neither genotypic nor phenotypic
A

phenotypic, not genotypic

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19
Q

Which example below is a case of disruptive selection?

  • Wolves and coyotes are hybridizing, which has led to the transfer of some wolf genetic variation into coyotes. This new genetic variation is allowing coyotes to become larger, and thus has made them better at hunting larger prey.
  • A squirrel population became established in an area with a new food item that was toxic, but nutritious. Over evolutionary time, this population evolved adaptations to detoxify the food item.
  • Climate warming is favoring physiological traits in mice that are more efficient at warmer temperatures.
  • Owls are visual hunters and are preying on mice that are living on dark and light-colored soils. The owls are preying on a higher frequency of lighter-colored mice in the dark soils and a higher-frequency of darker-colored mice in the light soils.
A

Owls are visual hunters and are preying on mice that are living on dark and light-colored soils. The owls are preying on a higher frequency of lighter-colored mice in the dark soils and a higher-frequency of darker-colored mice in the light soils.

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20
Q

Variation is generated in a population primarily by

  • changing environmental conditions.
  • natural selection.
  • inheritance.
  • mutation.
A

mutation

21
Q

In a population of bats, a particular phenotype is under the control of a single genetic locus. All genotypes with two copies of the B2 allele are at a selective disadvantage over other genotypes. Previous research has indicated that this is a two-allele system where individuals that possess the homozygous recessive genotype (i.e., B2B2) have a relative fitness of 0.95 (i.e., a selection coefficient of 0.05) that of the dominant genotype. Calculate the average fitness (wbar) of this population if the allele frequency of the B1 alleles is 0.43.

  • 0.9838
  • It is impossible to answer the question given the information provided.
  • 0.6913
  • 0.7387
A

0.9838

22
Q

Which evolutionary force increases heterozygosity?

  • Directional Selection
  • Self-Fertilization
  • Drift
  • Gene Flow
A

Gene Flow

23
Q

Would you expect genetic variation in a species under directional selection to:

  • Decrease
  • Remain Constant
  • Increase
A

Decrease

24
Q

Snails have a genome size of 3 X 109 (3,000,000,000) base pairs and a mutation rate of approximately 2.5 x 10-8 (0.000000025) mutations per site per generation. How many novel mutations would we expect each baby snail in the next generation to have?

  • 3 X 10^9 * (2)( 2.5 x 10^-8) or 150
  • 3 X 10^9 bp * 2.5 x 10^-8 or ~75
  • 3 X 10^9 bp / 2.5 x 10^-8 or ~1,200,000,000
  • It is impossible to answer given the information provided.
A

3 X 10^9 bp * 2.5 x 10^-8 or ~75

25
Q

Which of the following is not a requirement for natural selection to act to change allele frequencies in a population:

  • That the variation is heritable
  • That there is variance in reproductive success
  • That reproductive success is dependent in some way on the genetic variation
  • That within-population genetic variation is present
  • That the population mates at random
A

That the population mates at random

26
Q

Choose the correct answer: Genetic drift influences evolution by:

  • all of the answers are correct
  • acting in combination with dispersal to dramatically shift allele frequencies in newly founded populations
  • reducing genetic diversity during population bottlenecks
  • reducing the average heterozygosity of populations
  • removing genetic variation from populations that are very large in size
A

all of the answers are correct

27
Q

Silent mutations:

  • result in a change in the amino acid sequence
  • result in a new phenotype
  • only occur at the 3rd codon position
  • do not change the amino acid sequence
  • No answer text provided.
A

do not change the amino acid sequence

28
Q

In a population of diploid snails of size N=1000, what is the probability that a novel allele caused by a new mutation at a locus that previously only had one allele will increase to fixation as a result of genetic drift?

  • 0.9998
  • 0.0002
  • 0.0001
  • 0.0005
  • 0.9995
A

0.0005

29
Q

Which of the following statements describes genetic draft (be careful: this is different from drift)?

  • a neutral allele that is changing in frequency because it is linked (hitchhiking) with another locus under selection
  • a neutral allele that is introduced into a population from another population.
  • a neutral allele that is randomly changing in frequency.
  • a neutral allele that is not changing in allele frequencies.
A

a neutral allele that is changing in frequency because it is linked (hitchhiking) with another locus under selection

30
Q

Fill in the blanks to make the following sentence true: The _______________________ theory of Ohta and Kimura states that mutations are effectively neutral when the _________________ is equal to or less than 1/2Ne.

  • nearly neutral, heterozygous effect
  • selective drive, inbreeding coefficient
  • adaptive, Darwinian fitness
  • nearly neutral, selection coefficient
  • genetic drive, mutation rate
A

nearly neutral, selection coefficient

31
Q

Which of the following is most likely to break up linkage disequilibrium?

  • mutation
  • drift
  • selection
  • recombination
A

recombination

32
Q

The breeder’s equation is useful for measuring the magnitude of evolutionary change in a trait. A biologist studying directional selection on color darkness in wild mice found a selection differential to be 0.8 and the selection response to be 0.6. What is the variability (i.e., heritability) of this trait in this population?

  • 0.8
  • 0.75
  • 1.33
  • 1
A

0.75

33
Q

Broad-sense heritability is defined as the ________ genetic variation divided by the ________ variation.

  • additive; total phenotypic
  • dominance; total phenotypic
  • total; total phenotypic
  • additive; total dominance
A

total; total phenotypic

34
Q

What maintains genetic diversity in populations?

  • the neutral view is that genetic diversity is maintained by mutation
  • the neutral view is that most alleles at polymorphic loci are functionally and selectively equivalent and maintained by genetic drift
  • the balanced view is that a variety of forces maintain genetic diversity
  • both ‘the balanced view is that genetic diversity is maintained by natural selection’ and ‘the neutral view is that genetic diversity is maintained by mutation’ are likely to be important
  • the balanced view is that genetic diversity is maintained by natural selection
A

both ‘the balanced view is that genetic diversity is maintained by natural selection’ and ‘the neutral view is that genetic diversity is maintained by mutation’ are likely to be important

35
Q

A biologist is studying the genetics of increasing pelvic size in humans. There are hundreds of genes controlling skeletal growth. In a selection analysis of one particular skeletal gene, the scientist found a dN/dS ratio < 1. Is the evolution of this gene consistent with evolution of increasing pelvic size.

  • True
  • False
A

False

36
Q

What assumption makes the Wright-Fisher model more realistic than the Hardy-Weinberg Equilibrium model?

  • Gene Flow is absent
  • Non-random mating
  • Finite Population Size
  • No Selection
A

Finite Population Size

37
Q

Two genetic loci are suspected of being in linkage disequilibrium. At the Pitx gene two alleles are observed in a population, the most common (Pitx1) with a frequency of 0.7. At the eda gene, two alleles are also observed, with the most common (eda1) at a frequency of 0.58. The four haplotype (i.e., multilocus genotype) frequencies are as follows: Pitx1 eda1= 0.299592 Pitx1 eda2 = 0.042408 Pitx2 eda2 = 0.081592 Pitx2 eda1 = 0.576408 Are these loci in linkage disequilibrium in this population?

  • No, because D ≠ 0. We use the coefficient of linkage disequilibrium to identify loci that are genetically linked, and interpret a value of D ≠ 0 to mean that the loci are in linkage equilibrium.
  • No, because D = 0. We use the coefficient of linkage disequilibrium to identify loci that are genetically linked, and interpret a value of D = 0 to mean that the loci are in linkage equilibrium.
  • Yes, because D ≠ 0. We use the coefficient of linkage disequilibrium to identify loci that are genetically linked, and interpret a value of D ≠ 0 to mean that the loci are in linkage disequilibrium.
  • Yes, because D = 0. We use the coefficient of linkage disequilibrium to identify loci that are genetically linked, and interpret a value of D = 0 to mean that the loci are in linkage disequilibrium.
A

No, because D = 0. We use the coefficient of linkage disequilibrium to identify loci that are genetically linked, and interpret a value of D = 0 to mean that the loci are in linkage equilibrium.

38
Q

Which of the following processes causes a neutral allele to increase in frequency because it is linked to an allele under selection?

  • mutation
  • background selection
  • genetic hitchhiking
  • genetic drift
A

genetic hitchhiking

39
Q

True or False: Drosophilids on the Hawaiian islands speciate in part due to founder effect.

A

True

40
Q

Darwin’s dilemma refers to what?

  • His misplaced views about blending inheritance, which prevented his explanation for the mechanism of natural selection from being accepted by his peers.
  • His struggles with reconciliation of his Christian faith and his views about evolution.
  • His guilt over his marriage to his (very) attractive and wealthy cousin.
  • His inability to understand how natural selection could lead to the evolution of unfit offspring of crosses between two parental types in a hybrid zone.
A

His inability to understand how natural selection could lead to the evolution of unfit offspring of crosses between two parental types in a hybrid zone.

41
Q

Sympatry describes the geographic ranges of two or more evolutionary lineages or species that overlap in space, whereas allopatry describes the geographic ranges of two or more evolutionary lineages or species that are not overlapping. Where is reinforcement likely to occur?

  • In insect systems where species are allopatric and males display behaviors associated with mating.
  • In geographic regions of secondary sympatry between two divergent lineages who shared a recent common ancestor.
  • In geographic regions of secondary allopatry between two different species who did not share a recent common ancestor.
  • in tropical ecosystems
  • In geographic regions where there are multiple sympatric species of the same genus, such that competition among species leads to adaptive specialization.
A

In geographic regions of secondary sympatry between two divergent lineages who shared a recent common ancestor.

42
Q

In Rhagoletis fruit flies, which lay their eggs in rotting fruit, Guy Bush suggested that sympatric speciation may be occurring due to differences in the timing of the emergence of adult flies. Given the figure below, what assumption did Bush make about the action of natural selection on Rhagoletis?

Fig. 5. Emergence period of the apple and hawthorn races of Rhagoletis pomonella. The cross hatched curve represents the approximate period of fruit maturation when larvae are leaving the fruit and pupating in the soil.

  • That flies who emerged when few ripe fruits were available would be reproductively successful.
  • Both the ‘flies who emerged when few ripe fruits were available would be reproductively successful’ and the ‘flies who specialized on a single resource would be leave fewer offspring than the more generalist flies’ were assumed by Bush.
  • That flies who specialized on a single resource would be leave fewer offspring than the more generalist flies.
  • That flies who emerged when few ripe fruits were available would not be reproductively successful.
A

That flies who emerged when few ripe fruits were available would not be reproductively successful.

43
Q

After the retreat of the last glaciers some 20,000 years before present, a hybrid zone was formed between two populations of salamanders that were isolated in separate glacial refugia during the Pleistocene Ice Age. What is the best inference that we could make if we observe that a hybrid zone is present, and what prediction could we make about the ultimate fate of this hybrid zone?

  • We would infer that there is a large difference in the darwinian fitness of the parental salamander populations, and predict that natural selection would eventually lead to the evolution of new species.
  • We would infer that there is not a large difference in the darwinian fitness of the parental salamander populations, and predict that reinforcement would eventually lead to the formation of new species.
  • We would infer that there is not a large difference in the darwinian fitness of the parental salamander populations, and predict that these populations would eventually merge and become a single population.
  • We would infer that there is a large difference in the darwinian fitness of the parental salamander populations, and predict that the more fit population would eventually outcompete the other population.
A

We would infer that there is not a large difference in the darwinian fitness of the parental salamander populations, and predict that these populations would eventually merge and become a single population.

44
Q

Match the reproductive barrier with the correct isolating mechanism

divergent genital morphology

divergent flowering time for pollinator host plants

hybrid female sterility

hybrid-host plant incompatibility

A

prezygotic, mechanical

prezygotic, temporal

postzygotic, intrinsic

postzygotic extrinsic ecological inviability

45
Q

Which is an example of postzygotic, intrinsic hybrid inviability

  • Eggs from hybridizing butterflies never hatch
  • Hybrid butterflies reach sexual maturity, but are outcompeted by the parental species for resources (habitat or food)
  • Sperm from one butterfly species isn’t compatible with the egg of the other butterfly species
  • Butterfly hybrids reach sexual maturity, but neither parental species will court with hybrids for mating opportunities
A

Eggs from hybridizing butterflies never hatch

46
Q

The Mimulus monkey flowers investigated by Bradshaw et al. demonstrate what about the loci that code for traits that are relevant to speciation?

  • how linkage disequilibrium can accumulate in the genome
  • nothing - their investigation was a colossal failure
  • that heterozygote advantage has an effect on the phenotype
  • that some alleles are obvious in their phenotypic effects
  • the importance of seed dispersal in angiosperms
A

that some alleles are obvious in their phenotypic effects

47
Q

In a case of hybrid speciation, hybrids freely court each other for mating opportunities, but do not court either parental species. The mechanism of reproductive isolation that is evolving in the hybrid species with respect to courtship is which of the following:

  • postzygotic intrinsic - hybrid inviability
  • postzygotic extrinsic – behavioral inviability
  • prezygotic behavioral isolation
  • postzygotic intrinsic - hybrid infertility
A

prezygotic behavioral isolation

48
Q

Under the general lineage concept proposed by deQuieroz, species can best be described as

  • A combination of ecological and morphological species concepts
  • Reproductively isolated gene pools
  • Evolutionary lineages, but lines of evidence for species varies by taxonomic group
  • As a combination of ecological, morphological, and biological species concepts
A

Evolutionary lineages, but lines of evidence for species varies by taxonomic group