Biology Chapter 23

  1. Sparrows with average-sized wings survive
    severe storms better than those with longer or shorter wings,
    stabilizing selection.
  2. No two people are genetically identical,
    except for identical twins. The chief cause of genetic variation among
    human individuals is
    • the reshuffling of alleles in sexual
    • reproduction.
  3. Natural selection changes allele
    frequencies in populations because some __________ survive and reproduce
    more successfully than others.
  4. There are 40 individuals in population 1,
    all of which have genotype A1A1, and there are 25 individuals in
    population 2, all of genotype A2A2. Assume that these populations are
    located far from one another and that their environmental conditions are
    very similar. Based on the information given here, the observed genetic
    variation is mostly likely an example of
    genetic drift.
  5. A fruit fly population has a gene with two
    alleles, A1 and A2. Tests show that 70% of the gametes produced in the
    population contain the A1 allele. If the population is in Hardy-Weinberg
    equilibrium, what proportion of the flies carry both A1 and A2?
  6. There are those who claim that the theory
    of evolution cannot be true because the apes, which are supposed to be
    closely related to humans, do not likewise share the same large brains,
    capacity for complicated speech, and tool-making capability. They reason
    that if these features are generally beneficial, then the apes should
    have evolved them as well. Which of these provides the best argument
    against this misconception?
    Advantageous alleles do not arise on demand.
  7. A proficient engineer can easily design
    skeletal structures that are more functional than those currently found
    in the forelimbs of such diverse mammals as horses, whales, and bats.
    That the actual forelimbs of these mammals do not seem to be optimally
    arranged is because
    • natural selection is generally limited to
    • modifying structures that were present in previous generations and in
    • previous species.
  8. The same gene that causes various coat
    patterns in wild and domesticated cats also causes the cross-eyed
    condition in these cats, the cross-eyed condition being slightly
    maladaptive. In a hypothetical environment, the coat pattern that is
    associated with crossed eyes is highly adaptive, with the result that
    both the coat pattern and the cross-eyed condition increase in a feline
    population over time. Which statement is supported by these
    • Phenotype is often the result of
    • compromise.
  9. When imbalances occur in the sex ratio of
    sexual species that have two sexes (i.e., other than a 50:50 ratio), the
    members of the minority sex often receive a greater proportion of care
    and resources from parents than do the offspring of the majority sex.
    This is most clearly an example of
    frequency-dependent selection.
  10. Male satin bowerbirds adorn structures that
    they build, called "bowers," with parrot feathers, flowers, and other
    bizarre ornaments in order to attract females. Females inspect the
    bowers and, if suitably impressed, allow males to mate with them. The
    evolution of this male behavior is due to
    sexual selection.
  11. If the curve shifts to the left or to the
    right, there is no gene flow, and the population size consequently
    increases over successive generations, then which of these is (are)
    probably occurring?1. immigration or emigration2.
    directional selection3. adaptation4. genetic drift5.
    disruptive selection
    directional selection and adaptation
  12. What is true of the trait whose frequency
    distribution in a large population appears above? It has probably
    stabilizing selection.
  13. Heterozygote advantage should be most
    closely linked to which of the following?

    70) Mules are relatively
    long-lived and hardy organisms that cannot, generally speaking, perform
    successful meiosis. Consequently, which statement about mules is true?
    stabilizing selection
  14. Mules are relatively long-lived and hardy
    organisms that cannot, generally speaking, perform successful meiosis.
    Consequently, which statement about mules is true?
    • They have a relative evolutionary fitness of
    • zero.
  15. The recessive allele that causes
    phenylketonuria (PKU) is harmful, except when an infant's diet lacks the
    amino acid, phenylalanine. What maintains the presence of this harmful
    allele in a population's gene pool?
  16. A certain species of land snail exists as
    either a cream color or a solid brown color. Intermediate individuals
    are relatively rare. Which of the following terms best describes this?
    disruptive selection
  17. The average birth weight for human babies
    is about 3 kg. Which of the following terms best describes this?
    stabilizing selection
  18. Fossil evidence indicates that horses have
    gradually increased in size over geologic time. Which of the following
    terms best describes this?
    directional selection
  19. Most Swiss starlings produce four to five
    eggs in each clutch. Those producing fewer or more than this have
    reduced fitness. Which of the following terms best describes this?
    stabilizing selection
  20. Which describes brightly colored peacocks
    mating more frequently than drab peacocks?
    sexual selection
Card Set
Biology Chapter 23
1st Set