What is true of microevolution?
It is evolution that involves only tiny changes to DNA, such as point mutations, producing only small (if any) changes to phenotype.
It is evolution that influences only a small subset of the populations that comprise a species.
It is the kind of evolution that can change the relative abundance of a particular allele in a gene pool over the course of generations.
It is evolution that is restricted to individual organisms.
It is evolution that results in the origin of small numbers of new species.
It is the kind of evolution that can change the relative abundance of a particular allele in a gene pool over the course of generations.
One of the following is NOT a source of genetic variation.
genetic drift
mutation
sexual
reproduction
alteration of gene number or position
rapid reproduction
genetic drift
The original source of all genetic variation is _____.
natural selection
independent assortment
sexual reproduction
mutation
recombination
mutation
Microevolutions occur when ________.
changes in allele
frequencies in a population occur over generations
gene flow
evenly transfers alleles between populations
a bird has a beak
of a particular size that does not grow larger during a
drought
individuals within all species vary in their phenotypic traits
changes in allele frequencies in a population occur over generations
Which statement about variation is true?
All genetic variation produces phenotypic variation.
All new
alleles are the result of nucleotide variability.
All phenotypic
variation is the result of genotypic variation.
All nucleotide
variability results in neutral variation.
All new alleles are the result of nucleotide variability.
Which statement about the beak size of finches on the island of Daphne Major during prolonged drought is true?
Each bird evolved a deeper, stronger beak as the drought
persisted.
The frequency of the strong-beak alleles increased in
each bird as the drought persisted.
Each bird that survived the
drought produced only offspring with deeper, stronger beaks than seen
in the previous generation.
Each bird's survival was strongly
influenced by the depth and strength of its beak as the drought persisted.
Each bird's survival was strongly influenced by the depth and strength of its beak as the drought persisted.
Genetic variation ________.
is created by the direct action of natural selection
must be
present in a population before natural selection can act upon the
population
arises in response to changes in the
environment
tends to be reduced when diploid organisms produce gametes
must be present in a population before natural selection can act upon the population
Which of the following are basic components of the Hardy–Weinberg
model?
Allele frequencies, number of individuals in the
population
Allele frequencies in a subset of the
population
Allele frequencies, phenotype
frequencies
Frequencies of two alleles in a gene pool before and
after many random matings
Frequencies of two alleles in a gene pool before and after many random matings
Which of the following evolutionary forces consistently results in
adaptive changes in allele frequencies?
Inbreeding
Mutation
Selection
There is no
evolutionary force that results in adaptive changes in allele frequencies.
Selection
According to the Hardy-Weinberg theorem, the frequencies of alleles
in a population will remain constant if _____ is the only process that
affects the gene pool.
sexual reproduction
genetic
drift
sexual selection
immigration
mutation
sexual reproduction
Suppose 64% of a remote mountain village can taste phenylthiocarbamide (PTC) and must, therefore, have at least one copy of the dominant PTC taster allele. If this population conforms to Hardy-Weinberg equilibrium for this gene, what percentage of the population must be heterozygous for this trait?
40%
48%
32%
16%
48%
Which Hardy-Weinberg condition is affected by population size?
selection
gene flow
no mutation
genetic drift
genetic drift
Which one of the following conditions would allow gene frequencies to
change by chance?
gene flow
small
populations
mutation
large population
small populations
The higher the proportion of loci that are "fixed" in a
population, the lower are that population's ________.
nucleotide variability and average heterozygosity
average
heterozygosity
chromosome number
nucleotide variability
nucleotide variability and average heterozygosity
In the formula for determining a populations genotype frequencies,
the "pq" in the term 2pq is necessary because _____.
heterozygotes can come about in two ways
heterozygotes have
two alleles
the population is diploid
the population is
doubling in number
heterozygotes have two alleles
In peas, a gene controls flower color such that R = purple and r =
white. In an isolated pea patch, there are 36 purple-flowering plants
and 64 white-flowering plants. Assuming Hardy-Weinberg equilibrium,
what is the value of q for this population?
0.36
0.64
0.75
0.80
0.80
A large population of laboratory animals has been allowed to breed randomly for a number of generations. After several generations, 25% 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.
What is the estimated frequency of allele A in the gene pool?
0.125
0.50
0.25
0.75
0.50
What situation most likely explains the occasional high frequency of certain inherited disorders among human populations established by a small population?
mutation
nucleotide variability
gene flow
founder
effect
bottleneck effect
founder effect
Soon after the island of Hawaii rose above the sea surface (somewhat less than one million years ago), the evolution of life on this new island should have been most strongly influenced by ________.
habitat differentiation
a genetic bottleneck
sexual
selection
the founder effect
the founder effect
The Dunkers are a religious group that moved from Germany to
Pennsylvania in the mid-1700s. They do not marry with members outside
their own immediate community. Today, the Dunkers are genetically
unique and differ in gene frequencies, at many loci, from all other
populations including those in their original homeland. Which of the
following likely explains the genetic uniqueness of this population?
population bottleneck and Hardy-Weinberg
equilibrium
founder effect and genetic drift
heterozygote
advantage and stabilizing selection
mutation and natural selection
founder effect and genetic drift
In 1986, a nuclear power accident in Chernobyl, USSR (now Ukraine),
led to high radiation levels for miles surrounding the plant. The high
levels of radiation caused elevated mutation rates in the surviving
organisms, and evolutionary biologists have been studying rodent
populations in the Chernobyl area ever since. Based on your
understanding of evolutionary mechanisms, which of the following most
likely occurred in the rodent populations following the accident?
Mutation caused genetic drift and decreased
fitness.
Mutation caused the fixation of new
alleles.
Mutation led to increased genetic
variation.
Mutations caused major changes in rodent physiology
over time.
Mutation led to increased genetic variation.
What is the only evolutionary mechanism that consistently leads to
adaptive evolution? See Concept 23.4 (Page 495)
neutral variation
genetic drift
the bottleneck
effect
gene flow
natural selection
natural selection
How does diploidy help to preserve genetic variation?
It fosters the exchange of genes between different
populations.
It restricts the gene pool by chance events such as
floods or other catastrophic events.
It allows recessive alleles
that may not be favored in the current environment to be preserved in
the gene pool by propagation in heterozygotes.
It allows the
frequency of a recessive allele in a population to be predicted under
certain conditions.
It helps individual organisms make a greater
contribution to the gene pool of the next generation.
It allows recessive alleles that may not be favored in the current environment to be preserved in the gene pool by propagation in heterozygotes.
Arrange the following in order from most general to most
specific.
1 natural selection
2. microevolution
3.
intrasexual selection
4. evolution
5. sexual selection
4, 2, 1, 5, 3
1, 4, 2, 5, 3
4, 1, 2, 3, 5
4, 2,
1, 3, 5
4, 2, 1, 5, 3