Biology Chapter 23
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Sparrows with average-sized wings survive
severe storms better than those with longer or shorter wings,
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
Natural selection changes allele
frequencies in populations because some __________ survive and reproduce
more successfully than others.
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
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?
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.
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.
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
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
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
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.
directional selection and adaptation
What is true of the trait whose frequency
distribution in a large population appears above? It has probably
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?
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
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?
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?
The average birth weight for human babies
is about 3 kg. Which of the following terms best describes this?
Fossil evidence indicates that horses have
gradually increased in size over geologic time. Which of the following
terms best describes this?
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?
Which describes brightly colored peacocks
mating more frequently than drab peacocks?
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