ECU BIO 1200 Exam 1 Questions Fully
Solved Graded A+.
If a person scatters a handful of garden pea plant seeds in one 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.
Why do scientists consider vestigial structures evidence for evolution? - Answer Vestigial
structures are considered evidence for evolution because most structures do not exist in an
organism without serving some function either presently or in the past. A vestigial structure
indicates a past form or function that has since changed, but the structure remains present
because it had a function in the ancestor.
How does the scientific meaning of "theory" differ from the common vernacular meaning? -
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 vernacular can mean a guess or speculation about something, meaning that the
knowledge implied by the theory is 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 environments, which is the outcome of natural selection.
Solve for the genetic structure of a population with 12 homozygous recessive individuals (yy), 8
homozygous dominant individuals (YY), and 4 heterozygous individuals (Yy). - Answer p = (8*2
+ 4)/48 = .42; q = (12*2 + 4)/48 = .58; p^2 = .17; 2pq = .48; q^2 = .34
Explain the Hardy-Weinberg principle of equilibrium theory. - Answer The Hardy-Weinberg
principle of equilibrium is used to describe the genetic makeup of a population. The theory
states that a population's allele and genotype frequencies are inherently stable: unless some
kind of evolutionary force is acting upon the population, generation after generation of the
population would carry the same genes, and individuals would, as a whole, look essentially the
same.
Imagine you are trying to test whether a population of flowers is undergoing evolution. You
, Describe a situation in which a population would undergo the bottleneck effect and explain
what impact that would have on the population's gene pool. - Answer A hurricane kills a large
percentage of a population of sand-dwelling crustaceans—only a few individuals survive. The
alleles carried by those surviving individuals would represent the entire population's gene pool.
If those surviving individuals are not representative of the original population, the post-
hurricane gene pool will differ from the original gene pool.
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, more of their genes are
passed to the next generation. For example, a big, powerful male gorilla is much more likely
than a smaller, weaker one to become the population's silverback: the pack's leader who mates
far more than the other males of the group. Therefore, the pack leader will father more
offspring who share half of his genes and are likely to grow bigger and stronger like their father.
Over time, the genes for bigger size will increase in frequency in the population, and the
average body size, as a result, grow larger on average.
Explain what a cline is and provide examples. - Answer A cline is a type of geographic variation
that is seen in populations of a given species that vary gradually across an ecological gradient.
For example, warm-blooded animals tend to have larger bodies in the cooler climates closer to
the earth's poles, allowing them to better conserve heat. This is considered a latitudinal cline.
Flowering plants tend to bloom at different times depending on where they are along the slope
of a mountain. This is known as an altitudinal cline.
Give an example of a trait that may have evolved as a result of the handicap principle and
explain your reasoning. - Answer The peacock's tail is a good example of the handicap
principle. The tail, which makes the males more visible to predators and less able to escape, is
clearly a disadvantage to the bird's survival. But because it is a disadvantage, only the most fit
males should be able to survive with it. Thus, the tail serves as an honest signal of quality to the
females of the population; therefore, the male will earn more matings and greater reproductive
success.
List the ways in which evolution can affect population variation and describe how they influence
allele frequencies. - Answer There are several ways evolution can affect population variation:
stabilizing selection, directional selection, diversifying selection, frequency-dependent selection,
and sexual selection. As these influence the allele frequencies in a population, individuals can
either become more or less related, and the phenotypes displayed can become more similar or
more disparate.
Solved Graded A+.
If a person scatters a handful of garden pea plant seeds in one 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.
Why do scientists consider vestigial structures evidence for evolution? - Answer Vestigial
structures are considered evidence for evolution because most structures do not exist in an
organism without serving some function either presently or in the past. A vestigial structure
indicates a past form or function that has since changed, but the structure remains present
because it had a function in the ancestor.
How does the scientific meaning of "theory" differ from the common vernacular meaning? -
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 vernacular can mean a guess or speculation about something, meaning that the
knowledge implied by the theory is 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 environments, which is the outcome of natural selection.
Solve for the genetic structure of a population with 12 homozygous recessive individuals (yy), 8
homozygous dominant individuals (YY), and 4 heterozygous individuals (Yy). - Answer p = (8*2
+ 4)/48 = .42; q = (12*2 + 4)/48 = .58; p^2 = .17; 2pq = .48; q^2 = .34
Explain the Hardy-Weinberg principle of equilibrium theory. - Answer The Hardy-Weinberg
principle of equilibrium is used to describe the genetic makeup of a population. The theory
states that a population's allele and genotype frequencies are inherently stable: unless some
kind of evolutionary force is acting upon the population, generation after generation of the
population would carry the same genes, and individuals would, as a whole, look essentially the
same.
Imagine you are trying to test whether a population of flowers is undergoing evolution. You
, Describe a situation in which a population would undergo the bottleneck effect and explain
what impact that would have on the population's gene pool. - Answer A hurricane kills a large
percentage of a population of sand-dwelling crustaceans—only a few individuals survive. The
alleles carried by those surviving individuals would represent the entire population's gene pool.
If those surviving individuals are not representative of the original population, the post-
hurricane gene pool will differ from the original gene pool.
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, more of their genes are
passed to the next generation. For example, a big, powerful male gorilla is much more likely
than a smaller, weaker one to become the population's silverback: the pack's leader who mates
far more than the other males of the group. Therefore, the pack leader will father more
offspring who share half of his genes and are likely to grow bigger and stronger like their father.
Over time, the genes for bigger size will increase in frequency in the population, and the
average body size, as a result, grow larger on average.
Explain what a cline is and provide examples. - Answer A cline is a type of geographic variation
that is seen in populations of a given species that vary gradually across an ecological gradient.
For example, warm-blooded animals tend to have larger bodies in the cooler climates closer to
the earth's poles, allowing them to better conserve heat. This is considered a latitudinal cline.
Flowering plants tend to bloom at different times depending on where they are along the slope
of a mountain. This is known as an altitudinal cline.
Give an example of a trait that may have evolved as a result of the handicap principle and
explain your reasoning. - Answer The peacock's tail is a good example of the handicap
principle. The tail, which makes the males more visible to predators and less able to escape, is
clearly a disadvantage to the bird's survival. But because it is a disadvantage, only the most fit
males should be able to survive with it. Thus, the tail serves as an honest signal of quality to the
females of the population; therefore, the male will earn more matings and greater reproductive
success.
List the ways in which evolution can affect population variation and describe how they influence
allele frequencies. - Answer There are several ways evolution can affect population variation:
stabilizing selection, directional selection, diversifying selection, frequency-dependent selection,
and sexual selection. As these influence the allele frequencies in a population, individuals can
either become more or less related, and the phenotypes displayed can become more similar or
more disparate.
