Biology 1407 test exam queries and
answers graded A+
Had Wallace died before sending a letter to Darwin, which circumstance would be most likely? -
ANS✅✅Darwin would have published his evolutionary theory later than he did.
In a plant population, the genotypes that grow fastest tend to be the most sensitive to drought. This
is an example of _______, and it tends to _______ evolution. - ANS✅✅a trade-off; constrain
Evolution is most likely to be constrained by - ANS✅✅pre-existing traits.
A sparrow population currently eats seeds that are mostly of medium size. Larger birds prefer
somewhat larger seeds and smaller birds prefer somewhat smaller seeds. The population currently is
experiencing stabilizing selection for body size. Which condition will most likely lead to directional
selection for smaller size? - ANS✅✅More seeds that are smaller in size
A population of swallowtail butterflies has an allele frequency of 60 percent for one allele of a locus
with two alleles. Out of 3,000 individuals, _______ should be homozygotes for the less common
allele if the population is at Hardy-Weinberg equilibrium. - ANS✅✅480
In a population at Hardy-Weinberg equilibrium with only two alleles at locus A, the frequency of A
alleles is 0.9. The frequency of heterozygotes for this allele is - ANS✅✅0.18.
Assuming there are only two alleles at a given locus, if the frequency of one allele is 0.3, what is the
frequency of the other allele? - ANS✅✅0.7
In a species of beetles, males that have large horns are better able to fight off other males for access
to females. This is an example of _______ selection. - ANS✅✅intrasexual
There are two isolated populations (A and B) of an endangered plant species. Population A has had a
constant size of 2,000 plants, and population B has had a constant size of 250 plants. We most
expect to see more changes in the frequency of neutral alleles in population _______ due to
_______. - ANS✅✅B; genetic drift
,Snapping shrimp have evolved very rapid movements in the structures they use to capture prey.
These rapid movements, which evolved through natural selection, can be considered a(n) _______,
and the process by which they evolved is called _______. - ANS✅✅adaptation; adaptation
Which is an example of evolution that is not adaptation? - ANS✅✅What was originally a rare
mutant coloration pattern becomes common through genetic drift in a small population of fish
Farmers are trying to produce shorter, wider lines of rice in order to improve yield. Despite imposing
selection on these traits, the lines are not getting shorter. Which is the most likely reason for the lack
of response? - ANS✅✅There is not enough genetic variation for the trait.
Which example best fits the description of natural selection? - ANS✅✅After a hurricane, the
frequency of spider colonies that are aggressive increases from what it was before, due to
differential survival.
Two populations of annelids (worms) live in distinct areas and on different soil types. Researchers
are interested in whether the populations have acquired different types of reproductive isolation.
Which method would be best to determine whether two populations exhibited temporal isolation? -
ANS✅✅Observe when each population is active. If they are active at different times, then they
exhibit temporal isolation.
Two populations of annelids (worms) live in distinct areas and on different soil types. Researchers
are interested in whether the populations have acquired different types of reproductive isolation.
Which method would be best to determine whether two populations exhibited gametic isolation? -
ANS✅✅Bring them into the lab. Observe single pairs of a male from one population and a female
from the other. See whether the sperm from the males of one population will fertilize eggs of the
females of the other. If they don't, then they exhibit gametic isolation.
Which scenario is least likely to lead to allopatric isolation? - ANS✅✅A lake dividing a population
of butterflies
Sympatric speciation - ANS✅✅is common in plants since many plant species can reproduce by
self-fertilization.
Darwin's finches on the Galápagos Islands - ANS✅✅evolved by allopatric speciation.
, Biologists take multiple measurements of head traits in grasshoppers. They find distinct differences
among different populations, and reclassify what had been populations of the same species as
several different species. Which species concept are they employing? - ANS✅✅Morphological
Three species of mosquitoes appear very similar, but DNA analysis reveals that they have been
evolving separately for at least the last 400,000 years and are evolutionarily distinct. These species
would thus be considered _______ species and have the biologists using the DNA analysis can be
said to be employing the _______ species concept. - ANS✅✅cryptic; lineage
In the western United States, populations of an annual plant can be found almost continuously from
San Diego to Seattle. Even though individuals from the San Diego and Seattle populations never
come into contact, they can still be considered part of the same species under the _______ species
concept because they can potentially interbreed. - ANS✅✅biological
Which statement best explains why the Hawaiian silverswords underwent an adaptive radiation and
the mainland tarweeds did not? - ANS✅✅The ancestors of the silverswords had more ecological
opportunities.
Which type of reproductive isolating mechanisms would most likely arise from the coevolution of
male and female reproductive organs in two sympatric populations of insects? -
ANS✅✅Mechanical
Which condition is most likely to lead to allopatric speciation? - ANS✅✅A river dividing a
population of small, nonflying crickets
A fly species in a particular geographic region has one phenotype/subpopulation with a preference
for cherries and another phenotype/ subpopulation with a preference for walnuts. These two groups
are partially reproductively isolated because the insects emerge from their pupae at different times
of the year. This species appears to be on its way toward - ANS✅✅sympatric speciation.
What is sympatric speciation? - ANS✅✅occurs when there are no physical barriers preventing any
members of a species from mating with another, and all members are in close proximity to one
another.
The Isthmus of Panama cut off gene flow between Atlantic and Pacific populations of a species of
fish. The cessation of gene flow led to the accumulation of genetic differences between the
populations, which then led to reproductive isolation. Now, Atlantic and Pacific populations of this
fish are separate species that cannot interbreed, even if they were again to come into contact with
each other. The process described here is that of - ANS✅✅allopatric speciation.
answers graded A+
Had Wallace died before sending a letter to Darwin, which circumstance would be most likely? -
ANS✅✅Darwin would have published his evolutionary theory later than he did.
In a plant population, the genotypes that grow fastest tend to be the most sensitive to drought. This
is an example of _______, and it tends to _______ evolution. - ANS✅✅a trade-off; constrain
Evolution is most likely to be constrained by - ANS✅✅pre-existing traits.
A sparrow population currently eats seeds that are mostly of medium size. Larger birds prefer
somewhat larger seeds and smaller birds prefer somewhat smaller seeds. The population currently is
experiencing stabilizing selection for body size. Which condition will most likely lead to directional
selection for smaller size? - ANS✅✅More seeds that are smaller in size
A population of swallowtail butterflies has an allele frequency of 60 percent for one allele of a locus
with two alleles. Out of 3,000 individuals, _______ should be homozygotes for the less common
allele if the population is at Hardy-Weinberg equilibrium. - ANS✅✅480
In a population at Hardy-Weinberg equilibrium with only two alleles at locus A, the frequency of A
alleles is 0.9. The frequency of heterozygotes for this allele is - ANS✅✅0.18.
Assuming there are only two alleles at a given locus, if the frequency of one allele is 0.3, what is the
frequency of the other allele? - ANS✅✅0.7
In a species of beetles, males that have large horns are better able to fight off other males for access
to females. This is an example of _______ selection. - ANS✅✅intrasexual
There are two isolated populations (A and B) of an endangered plant species. Population A has had a
constant size of 2,000 plants, and population B has had a constant size of 250 plants. We most
expect to see more changes in the frequency of neutral alleles in population _______ due to
_______. - ANS✅✅B; genetic drift
,Snapping shrimp have evolved very rapid movements in the structures they use to capture prey.
These rapid movements, which evolved through natural selection, can be considered a(n) _______,
and the process by which they evolved is called _______. - ANS✅✅adaptation; adaptation
Which is an example of evolution that is not adaptation? - ANS✅✅What was originally a rare
mutant coloration pattern becomes common through genetic drift in a small population of fish
Farmers are trying to produce shorter, wider lines of rice in order to improve yield. Despite imposing
selection on these traits, the lines are not getting shorter. Which is the most likely reason for the lack
of response? - ANS✅✅There is not enough genetic variation for the trait.
Which example best fits the description of natural selection? - ANS✅✅After a hurricane, the
frequency of spider colonies that are aggressive increases from what it was before, due to
differential survival.
Two populations of annelids (worms) live in distinct areas and on different soil types. Researchers
are interested in whether the populations have acquired different types of reproductive isolation.
Which method would be best to determine whether two populations exhibited temporal isolation? -
ANS✅✅Observe when each population is active. If they are active at different times, then they
exhibit temporal isolation.
Two populations of annelids (worms) live in distinct areas and on different soil types. Researchers
are interested in whether the populations have acquired different types of reproductive isolation.
Which method would be best to determine whether two populations exhibited gametic isolation? -
ANS✅✅Bring them into the lab. Observe single pairs of a male from one population and a female
from the other. See whether the sperm from the males of one population will fertilize eggs of the
females of the other. If they don't, then they exhibit gametic isolation.
Which scenario is least likely to lead to allopatric isolation? - ANS✅✅A lake dividing a population
of butterflies
Sympatric speciation - ANS✅✅is common in plants since many plant species can reproduce by
self-fertilization.
Darwin's finches on the Galápagos Islands - ANS✅✅evolved by allopatric speciation.
, Biologists take multiple measurements of head traits in grasshoppers. They find distinct differences
among different populations, and reclassify what had been populations of the same species as
several different species. Which species concept are they employing? - ANS✅✅Morphological
Three species of mosquitoes appear very similar, but DNA analysis reveals that they have been
evolving separately for at least the last 400,000 years and are evolutionarily distinct. These species
would thus be considered _______ species and have the biologists using the DNA analysis can be
said to be employing the _______ species concept. - ANS✅✅cryptic; lineage
In the western United States, populations of an annual plant can be found almost continuously from
San Diego to Seattle. Even though individuals from the San Diego and Seattle populations never
come into contact, they can still be considered part of the same species under the _______ species
concept because they can potentially interbreed. - ANS✅✅biological
Which statement best explains why the Hawaiian silverswords underwent an adaptive radiation and
the mainland tarweeds did not? - ANS✅✅The ancestors of the silverswords had more ecological
opportunities.
Which type of reproductive isolating mechanisms would most likely arise from the coevolution of
male and female reproductive organs in two sympatric populations of insects? -
ANS✅✅Mechanical
Which condition is most likely to lead to allopatric speciation? - ANS✅✅A river dividing a
population of small, nonflying crickets
A fly species in a particular geographic region has one phenotype/subpopulation with a preference
for cherries and another phenotype/ subpopulation with a preference for walnuts. These two groups
are partially reproductively isolated because the insects emerge from their pupae at different times
of the year. This species appears to be on its way toward - ANS✅✅sympatric speciation.
What is sympatric speciation? - ANS✅✅occurs when there are no physical barriers preventing any
members of a species from mating with another, and all members are in close proximity to one
another.
The Isthmus of Panama cut off gene flow between Atlantic and Pacific populations of a species of
fish. The cessation of gene flow led to the accumulation of genetic differences between the
populations, which then led to reproductive isolation. Now, Atlantic and Pacific populations of this
fish are separate species that cannot interbreed, even if they were again to come into contact with
each other. The process described here is that of - ANS✅✅allopatric speciation.
