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Evolution Exam Study Questions

Terms in this set (27)

Chihuahuas, Border Collies, and Great Danes (all domestic dogs) descend from the same wolf
species and can still interbreed. These varieties were produced by
artificial selection.
Which of the following best expresses the concept of natural selection?
differential reproductive success based on inherited traits
Which of the following represents a pair of homologous structures?
the wing of a bat and the flipper of a dolphin
Which of the following statements regarding natural selection is false?
Natural selection starts with the creation of new alleles that are directed
toward improving an organism's fitness.
A population is
a group of individuals of the same species living in the same place at the same
time.
Humans share several features with salamanders. Certain genes and proteins are nearly identical
between the two species; both species have four limbs with a similar skeletal structure; the
species' early embryos are very similar; and where the salamander has a functional tail, humans
have a vestigial tailbone. In evolutionary terms, these are examples of
homology
In the Hardy-Weinberg equation, the frequency of homozygous dominant individuals in a
population is equal to
p^2
Which of the following terms represents the frequency of heterozygotes in a population that is in
Hardy-Weinberg equilibrium?
2pq
Imagine that you are studying a very large population of moths that is isolated from gene flow. A
single gene controls wing color. Half of the moths have white-spotted wings (genotype WW or
Ww) and half of the moths have plain brown wings (ww). There are no new mutations,
individuals mate randomly, and there is no natural selection on wing color. How will p, the
frequency of the dominant allele, change over time?
p will increase; the dominant allele will eventually take over and become most
common in the population
Genetic differences between populations tend to be reduced by
gene flow
The recessive allele of a gene causes cystic fibrosis. For this gene among Caucasians, p = 0.98. If
a Caucasian population is in Hardy-Weinberg equilibrium with respect to this gene, what
proportion of babies is born homozygous recessive, and therefore suffers cystic fibrosis?
0.022 = 0.0004
A population of 1,000 birds exists on a small Pacific island. Some of the birds are yellow, a trait
determined by a recessive allele. The others are green, a characteristic determined by a dominant
allele. A hurricane on the island kills most of the birds from this population. Only ten remain,
and those birds all have yellow feathers. Which of the following statements is true?
The hurricane has caused a population bottleneck and a loss of genetic
diversity
Frequency-dependent selection, as seen in the case of the scale-eating fish in Lake Tanganyika,
tends to
maintain two phenotypes in a dynamic equilibrium in a population
If you had to choose, where would you rather get infected with a serious bacterial disease?
In a remote, sparsely populated area where the bacteria have not been exposed to
In natural selection, __________ determines which phenotypes are successful
the environment
The sickle-cell allele produces a serious blood disease in homozygotes. Why doesn't natural
selection eliminate this allele from all human populations?
In populations where endemic malaria is present, heterozygotes have an
important advantage: They are resistant to malaria and therefore are
more likely to survive and produce offspring that carry the allele
Tay-Sachs is inherited as an autosomal recessive allele. Homozygous individuals die within the
first few years of life. However, there is some evidence that heterozygous individuals are more
resistant to tuberculosis. Which of the following statements about Tay-Sachs is true?
This is an example where selection for the heterozygous individuals outweighs
selection against the homozygous individuals, and the allele stays in the
population
Animals that possess homologous structures probably _____.
have a common ancestor
Suppose that, with regard to a particular genetic locus with two alleles, A and a, we know that
60% of the alleles in the gene pool of a particular large population are A. Suppose further that we
observe this population for five generations, during which we know that no mutation, selection,
or migration has occurred. After this period, the frequency of the a allele is expected to be
0.4
The original source of all genetic variation is _____.
mutation
Which of the following is the best example of gene flow?
Wind blows pollen from one population of plants to another and crossfertilization occurs
The evolutionary effects of genetic drift are greatest when _____.
the population size is large
Each of us is part of the ongoing evolution of the human species. Which of the following would
have the greatest impact on the future biological evolution of the human population?
A mutation occurs in one of your sperm or egg cells
Scientists have warned doctors of the danger of their increasing use of antibiotics (for instance,
penicillin) for treating minor illnesses. They are concerned because ____________.
strains of microorganisms that are resistant to these drugs will be selected for.
In a population of bears, which is most likely to be considered to have the greatest Darwinian
fitness?
the bear that leaves the most descendants
Genetic drift results in a change in gene frequencies because
the population size is so small that chance occurrences can alter gene
frequencies
The morphological species concept:
defines species by observable and measurable physical traits
Verified questions
anatomy
The meaning of physiology, and the importance of studying the physiology of other species for understanding humans
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physics
A person has a reasonable chance of surviving an automobile crash if the deceleration is no more than $30 \mathrm{~g}$ 's. Calculate the force on a $65 \mathrm{~kg}$ person accelerating at this rate. What distance is traveled if brought to rest at this rate from $95 \mathrm{~km} / \mathrm{h}$ ?
Verified answer
chemistry
Explain why TLC is not suitable for use with compounds that have boiling points below about $150^{\circ} \mathrm{C}$ ($760$ torr).
Verified answer
chemistry
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