Biology
Ch. 16 Review
Which of the following statements describe
what all members of a population share?
1. They are temporally
isolated from each other.
2. They are geographically
isolated from each other.
3. They are members of the
same species.
4. They have identical genes.
0%
1
0%
0%
2
3
0%
4
All the genes of all members of a particular
population make up the population’s
1. relative
frequency.
2. phenotype.
3. genotype.
4. gene pool.
0%
1
0%
0%
2
3
0%
4
Which statement below about gene pools is
typically true?
1. They contain two or more
alleles for each inheritable
trait.
2. They contain only dominant
alleles.
3. They belong to two or more
interbreeding species.
4. The relative frequencies of
the alleles never change.
0%
1
0%
0%
2
3
0%
4
If an allele makes up one fourth of a
population’s alleles for a given trait, its
relative frequency is
1.
2.
3.
4.
100 percent.
75 percent.
25 percent.
4 percent.
0%
1
0%
0%
2
3
0%
4
Interbreeding among members of a
population results in
1. different types of alleles in the
gene pool.
2. changes in the relative frequencies
of alleles in the gene pool.
3. no changes in the relative
frequencies of alleles in the gene
pool.
4. an absence of genetic variation in 0%
the population.
1
0%
0%
2
3
0%
4
In a population, the sum of the relative
frequencies of all alleles for a particular trait
is
1. equal to 100 percent.
2. equal to the number of
alleles for the trait.
3. constantly changing.
4. dependent on the
number of alleles.
0%
1
0%
0%
2
3
0%
4
A change in a sequence of DNA
is called a
1. recombination.
2. polygenic trait.
3. single-gene trait.
4. mutation.
0%
1
0%
0%
2
3
0%
4
The two main sources of genetic variation are
1. genotypes and
phenotypes.
2. gene shuffling and
mutations.
3. single-gene traits and
polygenic traits.
4. directional selection and
disruptive selection.
0%
1
0%
0%
2
3
0%
4
In many kinds of organisms, inheritable
differences are due mostly to
1. mutations during
gamete formation.
2. polygenic traits.
3. gene shuffling during
gamete formation.
4. the effects of radiation.
0%
1
0%
0%
2
3
0%
4
Gene shuffling includes the independent
movement of chromosomes during
meoisis as well as
1. mutations from radiation.
2. changes in the frequencies
of alleles.
3. crossing-over.
4. mutations from chemicals.
0%
1
0%
0%
2
3
0%
4
In a particular population, sexual
reproduction can produce
1. mutations.
2. many different
phenotypes.
3. new allele
frequencies.
4. meiosis.
0%
1
0%
0%
2
3
0%
4
The gene shuffling that occurs as part of
sexual reproduction
1. changes the gene pool’s
allele frequencies.
2. does not change the gene
pool’s allele frequencies.
3. keeps the phenotypes
consistent.
4. is caused by radiation or
chemicals.
0%
1
0%
0%
2
3
0%
4
A single-gene trait that has two alleles
and that shows a simple dominantrecessive pattern will result in
1. one phenotype.
2. two phenotypes.
3. four phenotypes.
4. millions of
phenotypes.
0%
1
0%
0%
2
3
0%
4
An example of a single-gene trait is
1. widow’s peak in
humans.
2. weight of human
infants at birth.
3. height in humans.
4. beak size in the
Galápagos finches.
0%
1
0%
0%
2
3
0%
4
The number of phenotypes produced for a
given trait depends upon
1. the number of genes that control
the trait.
2. which form of the trait is
dominant.
3. the relative frequencies of the
various alleles.
4. the relationship of allele
frequencies to Mendelian ratios.
0%
1
0%
0%
2
3
0%
4
The phenotypes for a typical
polygenic trait can often be expressed
as
1. a bar graph.
2. a bell-shaped
curve.
3. Mendelian ratios.
4. allele frequencies.
0%
1
0%
0%
2
3
0%
4
Compared to a polygenic trait, a
single-gene trait tends to have
1. fewer phenotypes.
2. more phenotypes.
3. the same number of
phenotypes.
4. phenotypes that form
a bell-shaped curve.
0%
1
0%
0%
2
3
0%
4
A polygenic trait can have
1. many possible genotypes,
but few possible phenotypes.
2. many possible genotypes,
producing many possible
phenotypes.
3. fewer phenotypes than most
single-gene traits.
4. fewer genotypes than most
single-gene traits.
0%
1
0%
0%
2
3
0%
4
Natural selection acts directly on
1. alleles.
2. genes.
3. phenotypes.
4. mutations.
0%
1
0%
0%
2
3
0%
4
Which of the following is NOT a way in
which natural selection affects the
distribution of phenotypes?
1. directional selection
2. stabilizing selection
3. disruptive selection
4. chance events
0%
1
0%
0%
2
3
0%
4
When individuals at only one end of a
bell curve of phenotype frequencies have
high fitness, the result is
1. directional selection.
2. stabilizing selection.
3. disruptive selection.
4. genetic drift.
0%
1
0%
0%
2
3
0%
4
When individuals with an average form
of a trait have the highest fitness, the
result is
1. not predictable.
2. disruptive selection.
3. directional selection.
4. stabilizing selection.
0%
1
0%
0%
2
3
0%
4
In a population of finches in which one group
of birds has a short, parrotlike beak and
another group has a long, narrow beak, what
process has probably occurred?
1. directional selection
2. disruptive selection
3. stabilizing selection
4. genetic drift
0%
1
0%
0%
2
3
0%
4
If a mutation introduces a new skin color in a
lizard population, which factor might determine
whether the frequency of the new allele will
increase?
1. how many other alleles are present
2. whether the mutation makes some
lizards more fit for their
environment than other lizards
3. how many phenotypes the
population has
4. whether the mutation was caused by 0%
nature or by human intervention
1
0%
0%
2
3
0%
4
In genetic drift, allele
frequencies change because of
1. mutations.
2. chance.
3. natural selection.
4. genetic
equilibrium.
0%
1
0%
0%
2
3
0%
4
Which of the following events do
biologists consider a random change?
1. directional selection
2. speciation
3. disruptive selection
4. genetic drift
0%
1
0%
0%
2
3
0%
4
Genetic drift tends to occur in
populations that
1. are very large.
2. are small.
3. are formed from new
species.
4. have unchanging
allele frequencies.
0%
1
0%
0%
2
3
0%
4
The type of genetic drift that follows the
colonization of a new habitat by a small
group of individuals is called
1. the Hardy-Weinberg
principle.
2. the founder effect.
3. directional selection.
4. stabilizing selection.
0%
1
0%
0%
2
3
0%
4
One similarity between natural selection and
genetic drift is that both events
1. are based completely on
chance.
2. begin with one or more
mutations.
3. involve a change in a
population’s allele frequencies.
4. take place only in very small
groups.
0%
1
0%
0%
2
3
0%
4
The situation in which allele
frequencies of a population remain
constant is called
1. evolution.
2. genetic drift.
3. genetic
equilibrium.
4. natural selection.
0%
1
0%
0%
2
3
0%
4
One of the conditions required to
maintain genetic equilibrium is
1. natural selection.
2. mutations.
3. nonrandom mating.
4. no movement into or
out of the population.
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1
0%
0%
2
3
0%
4
The genetic equilibrium of a
population can be disturbed by each of
the following EXCEPT
1. nonrandom mating.
2. movement into and
out of the population.
3. a large population
size.
4. mutations.
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1
0%
0%
2
3
0%
4
The allele frequencies of a population are
more likely to remain unchanged if
1. the population size is
reduced.
2. frequent movement into and
out of the population occurs.
3. all mating is random.
4. the mutation rate increases.
0%
1
0%
0%
2
3
0%
4
According to the Hardy-Weinberg principle,
genetic equilibrium would be more likely in a
population of mice if
1. the population size rapidly
decreases.
2. mutation rates within the
population rise.
3. no natural selection takes
0%
0%
0%
0%
place.
4. there is frequent movement
into and out of the population.
1
2
3
4
Which factor would most likely disrupt
genetic equilibrium in a large
population?
1. the production of large
numbers of offspring
2. mating that is not random
3. the absence of movement
into and out of the
0% 0% 0% 0%
population
4. the absence of mutations
1
2
3
4
The separation of populations by
barriers such as rivers, mountains, or
bodies of water is called
1. temporal isolation.
2. geographic isolation.
3. behavioral isolation.
4. genetic equilibrium.
0%
1
0%
0%
2
3
0%
4
A factor that is necessary for the
formation of a new species is
1. reproduction at
different times.
2. geographic barriers.
3. different mating
behaviors.
4. reproductive isolation.
0%
1
0%
0%
2
3
0%
4
What situation might develop in a
population having some plants whose
flowers open at midday and other plants
whose flowers open late in the day?
1. behavioral isolation
2. geographic isolation
3. temporal isolation
4. genetic drift
0%
1
0%
0%
2
3
0%
4
The geographic isolation of two populations
of a species tends to increase differences
between their gene pools because it
1. prevents interbreeding
between the populations.
2. prevents interbreeding within
each population.
3. causes temporal isolation of
the two populations.
0% 0% 0% 0%
4. increases differences in
courtship behavior.
1
2
3
4
Although they often live in the same habitat, the
American toad breeds earlier in the spring than the
Fowler’s toad does. What can be inferred from this
information?
1. The two species do not interbreed
because of geographic isolation.
2. The two species do not interbreed
because of temporal isolation.
3. The two species interbreed
throughout the spring season.
0% 0% 0% 0%
4. The American toad will cause the
extinction of the Fowler’s toad.
1
2
3
4
Which is the first step that occurred in
the speciation of the Galápagos finches?
1. establishing genetic
equilibrium
2. behavioral isolation
3. ecological competition
4. arrival of the founding
population
0%
1
0%
0%
2
3
0%
4
The Galápagos finch species
are an excellent example of
1. speciation.
2. genetic equilibrium.
3. stabilizing selection.
4. selection on singlegene traits.
0%
1
0%
0%
2
3
0%
4
What did Peter and Rosemary Grant learn
about mate choice from the Galápagos
finches?
1. Phenotype plays no role in mate
choice.
2. Finches prefer mates with beaks
similar in size to their own.
3. Finches prefer mates with
smaller beaks than their own.
0% 0% 0% 0%
4. Finches prefer mates with larger
beaks than their own.
1
2
3
4
In Rosemary and Peter Grant’s study of
the Galápagos finches, what process was
encouraged by ecological competition
during the dry season?
1. stabilizing selection
2. disruptive selection
3. directional selection
4. genetic drift
0%
1
0%
0%
2
3
0%
4
Which statement about evolution in the
Galápagos finches is true?
1. Natural selection on beak size and
shape is driven by available food.
2. Stabilizing selection has favored an
intermediate beak type for all of the
finches.
3. Mate choice likely plays no role in
the finches’ evolution.
4. None of the finch species is
reproductively isolated.
0%
1
0%
0%
2
3
0%
4
Because all members of a population
can interbreed, biologists often study
their genes as a single group.
1.True
2.False
0%
1
0%
2
In a gene pool, as the relative
frequency of one allele for a
trait increases, the relative
frequencies of other alleles for
that trait decrease.
1. True
2. False
0%
1
0%
2
Most inheritable differences
are due to mutations that occur
during the production of
gametes.
1. True
2. False
0%
1
0%
2
Mutations do not always affect
an organism’s genotype—its
physical, behavioral, and
biochemical characteristics.
1. True
2. False
0%
1
0%
2
A polygenic trait is controlled
by one gene.
1. True
2. False
0%
1
0%
2
On a graph, the distribution of
phenotypes for a single-gene
trait tends to form a bellshaped curve.
1. True
2. False
0%
1
0%
2
Natural selection on single-gene
traits can lead to changes in
allele frequencies.
1. True
2. False
0%
1
0%
2
In a population of snakes with a
range of body lengths, if the longest
individuals have the highest fitness,
disruptive selection is likely to occur.
1. True
2. False
0%
1
0%
2
In small populations, an allele
can become more or less
common simply by chance.
1. True
2. False
0%
1
0%
2
Genetic drift may occur when a
small group of individuals
colonize a new habitat.
1. True
2. False
0%
1
0%
2
When mutations introduce new
alleles into a population,
genetic variation is disrupted.
1. True
2. False
0%
1
0%
2
In a population of birds, if females
prefer males with long tails, the
population violates the condition of
directional selection described by the
Hardy-Weinberg principle.
1. True
2. False
0%
1
0%
2
In the type of reproductive isolation
called behavioral isolation, two
populations are separated by
barriers such as rivers or mountains.
1. True
2. False
0%
1
0%
2
Two populations that have
overlapping ranges can remain
reproductively isolated through
behavioral isolation or temporal
isolation from each other.
1. True
2. False
0%
1
0%
2
The first step of the speciation of the
Galápagos finches likely was the
arrival of founders from South
America.
1. True
2. False
0%
1
0%
2