Question 1

Suppose in a population of 250,000 mice the mutation rate per nucleotide for a genetic locus is 4 × 10^-8.The locus contains 1,500 nucleotides.How many new mutations should we expect at this locus in each generation?

Accepted Answer

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Question 2

Which statement best exemplifies Lyell's ideas, which led Darwin to formulate his own views on evolution?

Accepted Answer

Lyell's ideas included the concept of uniformitarianism, which suggests that slow and gradual processes over long time periods can shape the Earth's surface. This idea influenced Darwin's understanding of how evolution occurred over long periods of time through small, incremental changes. Choice C best exemplifies this idea.

Question 3

In addition to Darwin, who do we credit for formulating the theory of evolution by natural selection?

Accepted Answer

Alfred Russel Wallace independently formulated the theory of evolution by natural selection around the same time as Darwin and published his findings simultaneously with Darwin.

Question 4

The numbers of fledged young of female song sparrows of different sizes were assayed and are presented in the table.  Assume that body size is at least partially heritable.Assume that all other aspects (survival, etc.) are independent of size.What type of selection, if any, is most likely occurring in population D? If selection is operating, what is the most likely effect of this selection on the phenotypic distribution?

Accepted Answer

The answer of The numbers of fledged young of female...

Question 5

Which observation from Darwin's stay in the Galápagos Islands was most instrumental toward his eventual development of evolutionary theory?

Accepted Answer

Darwin observed that animal species on the Galápagos Islands were similar to species on the South American mainland, but were unique to the islands. This observation suggested that species could adapt to their environment over time, which eventually led Darwin to propose the theory of evolution by natural selection.

Question 6

Evolution by natural selection requires

Accepted Answer

Evolution by natural selection requires genetic variation among individuals in a population. This variation allows for individuals with advantageous traits to survive and reproduce more successfully, leading to the spread of these traits within the population over time. Large or small populations and diploid individuals are not specifically necessary for natural selection, but genetic variation is essential. Selective breeding by humans is artificial selection, not natural selection.

Question 7

Which evolutionary process is most likely to increase the proportion of heterozygotes in a population?

Accepted Answer

Mutation introduces new alleles into a population, which can increase genetic diversity and the proportion of heterozygotes.

Question 8

Male whitetail deer produce antlers every year and then shed them after the breeding season.Discuss the trade-offs in this cycle.

Accepted Answer

The answer of Male whitetail deer produce antlers every year...

Question 9

A population of salmon is becoming increasingly small over the generations.This trend does not appear to be due to environmental changes, but rather to selection due to the fishing industry.Draw the relationship between body size and fitness that is occurring in this population.

Accepted Answer

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Question 10

The size of a particular appendage in many populations of beetles is determined by alleles at many genetic loci and is largely unaffected by selection.Initially, many populations start with about the same average size of the appendage.Assuming that genetic drift is the only evolutionary process operating, we would expect that over the course of many generations, the average size of the appendage would _______ and that there would be _______ difference in the size of the appendage among the different populations.

Accepted Answer

Genetic drift, especially in small populations, leads to random changes in allele frequencies over time. This can cause variations in traits like the appendage size among different populations. However, without selection acting on the trait, the average size within any given population is likely to stay about the same over generations. The differences among populations would increase due to the random nature of genetic drift affecting each population differently.

Question 11

A population of salmon is becoming increasingly small over succeeding generations.This trend does not appear to be due to environmental changes, but rather to selection due to the fishing industry.What type of selection is occurring?

Accepted Answer

The answer of A population of salmon is becoming increasingly...

Question 12

Draw the relationship between frequency of an allele (from 0.1 to 0.5) and its fitness in cases where frequency-dependent selection maintains genetic variation.

Accepted Answer

The answer of Draw the relationship between frequency of an...

Question 13

According to its scientific definition, a theory is

Accepted Answer

According to its scientific definition, a theory is based on a large body of knowledge, evidence, and experimentation, and is supported by extensive research and scientific reasoning. It is not merely a guess or supposition, but a well-established and proven explanation of a phenomenon in the natural world.

Question 14

Which of the following is not an example of adaptation?

Accepted Answer

The ability to better withstand colder temperatures after exposure to cold is not a genetic adaptation, but rather an acclimation response. Adaption refers to genetic changes that occur over multiple generations.

Question 15

Suppose the mutation rate per nucleotide for a genetic locus is 4 × 10^-8 and that the locus contains 1,500 nucleotides.What is the per-locus mutation rate?

Accepted Answer

To determine the per-locus mutation rate, we need to multiply the mutation rate per nucleotide by the number of nucleotides in the locus. Per-locus mutation rate = mutation rate per nucleotide × number of nucleotides Per-locus mutation rate = (4 × 10^-8) × 1500 Per-locus mutation rate = 6 × 10^-5 Therefore, the answer is B.

Question 16

Refer to the graph showing beak size for a population of a species of Darwin's finches.  Draw a graph showing what the resulting population would most likely look like after a generation of strong disruptive selection.

Accepted Answer

The answer of Refer to the graph showing beak size...

Question 17

The numbers of fledged young of female song sparrows of different sizes were assayed and are presented in the table.  Assume that body size is at least partially heritable.Assume that all other aspects (survival, etc.) are independent of size.What type of selection, if any, is most likely occurring in population C? If selection is operating, what is the most likely effect of this selection on the phenotypic distribution?

Accepted Answer

The answer of The numbers of fledged young of female...

Question 18

Refer to the graph showing beak size for a population of a species of Darwin's finches.  Draw a graph showing what the resulting population would most likely look like after a generation of directional selection for smaller beak size.

Accepted Answer

The answer of Refer to the graph showing beak size...

Question 19

In which way are mutation and gene flow most similar?

Accepted Answer

Both mutation and gene flow can introduce new genetic variations into a population, thus increasing the genetic diversity within a population. This is in contrast to genetic drift and natural selection, which tend to reduce genetic variation in a population.

Question 20

The survivorship of individuals from four different populations of a beetle species has been assayed and is presented in the table.TT, TC, and CC represent genotypes at a locus that is important in survival.  Assuming that genotypes at this locus have no other effects on fitness, would we expect variation to be maintained by selection in any of the populations? Why? What would be the expected outcomes in the populations in the absence of any other evolutionary processes?

Accepted Answer

The answer of The survivorship of individuals from four different...

Quiz 20: Mechanisms of Evolution

Suppose in a population of 250,000 mice the mutation rate per nucleotide for a genetic locus is 4 × 10-8.The locus contains 1,500 nucleotides.How many new mutations should we expect at this locus in each generation?