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11.E: Evolution and Its Processes (Exercises)

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    8089
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    11.1: Discovering How Populations Change

    Multiple Choice

    Which scientific concept did Charles Darwin and Alfred Wallace independently discover?

    A. mutation
    B. natural selection
    C. overbreeding
    D. sexual reproduction

    Answer

    B

    Which of the following situations will lead to natural selection?

    A. The seeds of two plants land near each other and one grows larger than the other.
    B. Two types of fish eat the same kind of food, and one is better able to gather food than the other.
    C. Male lions compete for the right to mate with females, with only one possible winner.
    D. all of the above

    Answer

    D

    What is the difference between micro- and macroevolution?

    A. Microevolution describes the evolution of small organisms, such as insects, while macroevolution describes the evolution of large organisms, like people and elephants.
    B. Microevolution describes the evolution of microscopic entities, such as molecules and proteins, while macroevolution describes the evolution of whole organisms.
    C. Microevolution describes the evolution of populations, while macroevolution describes the emergence of new species over long periods of time.
    D. Microevolution describes the evolution of organisms over their lifetimes, while macroevolution describes the evolution of organisms over multiple generations.

    Answer

    C

    Population genetics is the study of ________.

    A. how allele frequencies in a population change over time
    B. populations of cells in an individual
    C. the rate of population growth
    D. how genes affect embryological development

    Answer

    A

    Free Response

    If a person scatters a handful of plant seeds from one species in an area, how would natural selection work in this situation?

    Answer

    The plants that can best use the resources of the area, including competing with other individuals for those resources, will produce more seeds themselves and those traits that allowed them to better use the resources will increase in the population of the next generation.

    Explain the Hardy-Weinberg principle of equilibrium.

    Answer

    The Hardy-Weinberg principle of equilibrium states that a population’s allele frequencies are inherently stable. Unless an evolutionary force is acting upon the population, the population would carry the same genes at the same frequencies generation after generation, and individuals would, as a whole, look essentially the same.

    11.2: Mechanisms of Evolution

    Multiple Choice

    Galápagos medium ground finches are found on Santa Cruz and San Cristóbal islands, which are separated by about 100 km of ocean. Occasionally, individuals from either island fly to the other island to stay. This can alter the allele frequencies of the population through which of the following mechanisms?

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

    Answer

    C

    In which of the following pairs do both evolutionary processes introduce new genetic variation into a population?

    A. natural selection and genetic drift
    B. mutation and gene flow
    C. natural selection and gene flow
    D. gene flow and genetic drift

    Answer

    B

    Free Response

    Describe natural selection and give an example of natural selection at work in a population.

    Answer

    The theory of natural selection stems from the observation that some individuals in a population survive longer and have more offspring than others, thus passing on more of their genes to the next generation. For example, a big, powerful male gorilla is much more likely than a smaller, weaker gorilla to become the population’s silverback, the pack’s leader who mates far more than the other males of the group. The pack leader will, therefore, father more offspring, who share half of his genes, and are thus likely to also grow bigger and stronger like their father. Over time, the genes for bigger size will increase in frequency in the population, and the population will, as a result, grow larger on average.

    11.3: Evidence of Evolution

    Multiple Choice

    The wing of a bird and the arm of a human are examples of ________.

    A. vestigial structures
    B. molecular structures
    C. homologous structures
    D. analogous structures

    Answer

    C

    The fact that DNA sequences are more similar in more closely related organisms is evidence of what?

    A. optimal design in organisms
    B. adaptation
    C. mutation
    D. descent with modification

    Answer

    D

    Free Response

    Why do scientists consider vestigial structures evidence for evolution?

    Answer

    A vestigial structure is an example of a homologous structure that has apparently been reduced through evolution to a non-functional state because its function is no longer utilized by the species exhibiting it; therefore, any mutations which might reduce its structure are not selected against. The fact that the species has vestiges of the structure rather than no structure at all is evidence that it was present in an ancestor and evolved to non-functionality through accumulation of random mutations.

    11.4: Speciation

    Multiple Choice

    Which situation would most likely lead to allopatric speciation?

    A. A flood causes the formation of a new lake.
    B. A storm causes several large trees to fall down.
    C. A mutation causes a new trait to develop.
    D. An injury causes an organism to seek out a new food source.

    Answer

    A

    What is the main difference between dispersal and vicariance?

    A. One leads to allopatric speciation, whereas the other leads to sympatric speciation.
    B. One involves the movement of the organism, whereas the other involves a change in the environment.
    C. One depends on a genetic mutation occurring, whereas the other does not.
    D. One involves closely related organisms, whereas the other involves only individuals of the same species.

    Answer

    B

    Which variable increases the likelihood of allopatric speciation taking place more quickly?

    A. lower rate of mutation
    B. longer distance between divided groups
    C. increased instances of hybrid formation
    D. equivalent numbers of individuals in each population

    Answer

    B

    Free Response

    Why do island chains provide ideal conditions for adaptive radiation to occur?

    Answer

    Organisms of one species can arrive to an island together and then disperse throughout the chain, each settling into different niches, exploiting different food resources and, evolving independently with little gene flow between different islands.

    Two species of fish had recently undergone sympatric speciation. The males of each species had a different coloring through which females could identify and choose a partner from her own species. After some time, pollution made the lake so cloudy it was hard for females to distinguish colors. What might take place in this situation?

    Answer

    It is likely the two species would start to reproduce with each other if hybridization is still possible. Depending on the viability of their offspring, they may fuse back into one species.

    11.5: Common Misconceptions about Evolution

    Multiple Choice

    The word “theory” in theory of evolution is best replaced by ________.

    A. fact
    B. hypothesis
    C. idea
    D. alternate explanation

    Answer

    A

    Why are alternative scientific theories to evolution not taught in public school?

    A. more theories would confuse students
    B. there are no viable scientific alternatives
    C. it is against the law
    D. alternative scientific theories are suppressed by the science establishment

    Answer

    B

    Free Response

    How does the scientific meaning of “theory” differ from the common, everyday meaning of the word?

    Answer

    In science, a theory is a thoroughly tested and verified set of explanations for a body of observations of nature. It is the strongest form of knowledge in science. In contrast, a theory in common usage can mean a guess or speculation about something, meaning that the knowledge implied by the theory may be very weak.

    Explain why the statement that a monkey is more evolved than a mouse is incorrect.

    Answer

    The statement implies that there is a goal to evolution and that the monkey represents greater progress to that goal than the mouse. Both species are likely to be well adapted to their particular environment, which is the outcome of natural selection.


    This page titled 11.E: Evolution and Its Processes (Exercises) is shared under a CC BY 4.0 license and was authored, remixed, and/or curated by OpenStax.

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