Chapter
23: The Evolution of Populations Review
1) What is the most important missing evidence
or observation in Darwin's theory of 1859?
2) Which hypothesis of inheritance, common at
Darwin's time, caused many to question the ability of natural selection to
bring about adaptation in populations?
3) Which definition of evolution would have been
most foreign to Charles Darwin during his lifetime?
4) What is
true of the modern evolutionary synthesis?
Use
the following information to answer the questions below.
A large population of laboratory animals has been
allowed to breed randomly for a number of generations. After several
generations, 36% of the animals display a recessive trait (aa), the
same percentage as at the beginning of the breeding program. The rest of the
animals show the dominant phenotype, with heterozygotes
indistinguishable from the homozygous dominants.
5) What is the most reasonable conclusion that
can be drawn from the fact that the frequency of the recessive trait (a(A) has not changed over time?
6) What is the estimated frequency of allele a in the gene pool?
7) What proportion of the population is probably
heterozygous (A(A)
for this trait?
8) All of the following are criteria for
maintaining Hardy-Weinberg equilibrium involving two alleles except
9) In a Hardy-Weinberg
population with two alleles, A and a, that are in equilibrium, the
frequency of the allele a is 0.7. What is the percentage of the population that
is homozygous for this allele?
10) In a Hardy-Weinberg population with two
alleles, A and a, that are in equilibrium, the
frequency of allele a is 0.7. What is the percentage of the population that is
heterozygous for this allele?
11) In a Hardy-Weinberg population with two
alleles, A and a, that are in equilibrium, the
frequency of allele a is 0.2. What is the frequency of individuals with Aa genotype?
12) In a population with two alleles, A and a, the frequency of a is 0.50. What would be the frequency of heterozygotes if the population is
in Hardy-Weinberg equilibrium?
13) Most copies of
harmful recessive alleles in a sexual species are carried by individuals that
are
14) In a population with two alleles, A and a, the frequency of A is
0.2. Organisms that are homozygous for A die before reaching sexual maturity.
In five generations, what would be the frequency of individuals with aa
genotypes?
Use
the following information to answer the questions below.
In a hypothetical population of 1,000 people,
tests of blood-type genes show that 160 have the genotype AA, 480 have the genotype AB,
and 360 have the genotype BB.
15) What is the frequency of the A allele?
16) What is the frequency of the B allele?
17) What percentage of the population has type O
blood?
18) If there are 4,000 children born to this
generation, how many would be expected to have AB blood under the conditions of
Hardy-Weinberg equilibrium?
19) In peas, a gene controls flower color such
that R = purple and r = white. In an isolated pea patch,
there are 36 purple flowers and 64 white flowers. Assuming Hardy-Weinberg
equilibrium, what is the value of q for this population?
20) Which of the following is not a requirement for maintenance of
Hardy-Weinberg equilibrium?
21) Which factor is the most important in producing the variability that occurs in each
generation of humans?
22) Which of the following chromosomal mutations
can increase the mass of DNA present in an organism's genome, creating
superfluous DNA that may undergo further changes producing entirely new genes?
23) In a large, sexually reproducing population,
the frequency of an allele changes from 0.6 to 0.2. From this change, one can
most logically assume that, in this environment,
24) The following
important concepts of population genetics are due to random events or chance except
25) Natural selection is most nearly the same as
26) Through time, the movement of people on Earth
has steadily increased. This has altered the course of human evolution by
increasing
27) Gene flow is a concept best used to describe
an exchange between
The
following questions refer to this information:
In the year 2500, five male space colonists and
five female space colonists (all unrelated to each other) settle on an
uninhabited Earthlike planet in the Andromeda galaxy. The colonists and their
offspring randomly mate for generations.
All ten of the original colonists had free earlobes, and two were
heterozygous for that trait. The allele
for free earlobes is dominant to the allele for attached earlobes.
28) Which of these is closest to the allele
frequency in the founding population?
29) If one assumes that Hardy-Weinberg
equilibrium applies to the population of colonists on this planet, about how
many people will have attached earlobes when the planet's population reaches
10,000?
30) If four of the original colonists died before
they produced offspring, the ratios of genotypes could be quite different in
the subsequent generations. This is an example of
31) Which of the
following is one important evolutionary feature of the diploid condition?
32) The Darwinian
fitness of an individual is measured by
33) If a phenotypic polymorphism lacks a genetic
component, then
34) When we
say that an individual organism has a greater fitness than another individual,
we specifically mean that the organism
35) Which of the following statements best
summarizes evolution as it is viewed today?
36) If neutral variation is truly
"neutral," then it should have no effect on
Choose among these options to answer the
following questions. Each option may be used once, more than once, or not at
all.
A. random
selection
B. directional
selection
C. stabilizing
selection
D. disruptive
selection
E. sexual
selection
37) An
African butterfly species exists in two strikingly different color
patterns.
38)
Brightly colored peacocks mate more frequently than do drab peacocks.
39) Most Swiss starlings produce four to five
eggs in each clutch.
40) Fossil evidence indicates that horses have
gradually increased in size over geologic time.
41) The average birth weight for human babies is
about 3 kg.
42) A certain species of land snail exists as
either a cream color or a solid brown color. Intermediate individuals are
relatively rare.
43) Pathogenic bacteria found in many hospitals
are antibiotic resistant.
44) Cattle
breeders have improved the quality of meat over the years by which process?
45) The 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?
46) Mules are relatively long-lived and hardy
organisms that cannot, generally speaking, perform successful meiosis. Which statement about mules is true?
47) Heterozygote advantage should be most closely
linked to which of the following?
48) A balanced polymorphism exists through
disruptive selection in seedcracker finches from
Cameroon in which small- and large-billed birds specialize in cracking soft and
hard seeds, respectively. If long-term climatic change resulted in all seeds
becoming hard, what type of selection would then operate on the finch
population?
49) Which of the following is most likely to have
been produced by sexual selection?
50) Female wasps, which are protected by the use
of a painful stinger, often make their presence conspicuous by rapidly moving
their usually long antennae. These wasps are often mimicked by flies with short
antennae who give the appearance of rapidly moving long antennae by waving
their forelegs in front of their bodies. Which of the following statements
concerning this behavior is not
consistent with current evolutionary theory?
51) In the hypothetical insect population you
examined in the activity "Causes of Microevolution," the genotypic
frequency of the green and red bugs changed significantly after a windstorm
randomly blew away individuals from the home plant. This change in genotypic
frequency can be attributed to
52) What is the result
of natural selection?
53) All the genes in a
population are the population's
54) In a cell in which 2n = 6, the independent assortment of chromosomes during meiosis can by
itself give rise to ________ genetically different gametes.
55) In sexually reproducing organisms, the events
of ________ do not contribute to an
increase in genetic variation.
56) The average length of jackrabbit ears
decreases gradually with increasing latitude. This variation is an example of
57) Natural selection changes allele frequencies
in populations because some ________ survive and 58) Longer tails of male barn swallows evolve
because female barn swallows prefer to mate with the males that have the
longest tails. This process is best described as
59) No two human
individuals are alike, except for identical twins. The chief cause of the
variation among individuals is
60) Sparrows with
average-sized wings survive severe storms better than those with longer or
shorter wings, illustrating
stabilizing selection.