Chapter 13 Flashcards
A small population of wolves founded by a single breeding pair on the Scandinavian peninsula
in 1983 showed little vitality until 1991, when the population began to grow exponentially.
What event in 1991 led to the increased vitality of the population?
A) several years of unusually mild winters
B) infusion of new genes into the pack by a single immigrant male
C) cessation of hunting by humans
D) recovery of the Scandinavian caribou herd
E) all of the above
B) infusion of new genes into the pack by a single immigrant male
Genetic analyses are finding new applications in ecology, leading to the understanding of the
geographic structure of natural populations, mating relationships, movements of individuals
within populations, and histories of change in population size.
A) True B) False
A) True
A given amino acid is encoded by only a single, unique base sequence in DNA.
A) True B) False
B) False
A point mutation (substitution of a single nucleotide in a DNA codon) in a gene for a particular
protein always results in a change in the amino acid sequence in the corresponding protein.
A) True B) False
B) False
Although there may be many different alleles of a particular gene in the gene pool for a
population, each diploid individual can only carry a small portion of that genetic variation.
A) True B) False
A) True
Microsatellites are tandem repeats of sequences of two, three, or four nucleotides in an individual’s DNA. Although noncoding, these microsatellites are useful as \_\_\_\_\_\_\_\_\_\_. A) safeguards against mutation Chapter 13: Population Genetics 2 B) regulators of gene expression C) genetic markers D) attachment points for spindle fibers E) all of the above
C) genetic markers
Natural selection generally tends to reduce genetic variation. Which of the following can
maintain or even enhance the level of genetic variation present in a population?
A) mutation
B) immigration
C) spatial/temporal environmental variation
D) heterozygote superiority
E) all of the above
E) all of the above
The probability that an individual complex organism (such as a vertebrate) is likely to sustain
one or more mutations in some part of its genome during its lifetime is:
A) zero. B) slight, but close to zero. C) small. D) high.
D) high.
Although the human sickle‐cell gene causes debilitating anemia when expressed in homozygous
form, it persists at relatively high frequency in some African populations, because in
heterozygous condition, the sickle‐cell allele confers an advantage. What is that advantage?
A) protection against malaria
B) protection against ionizing effects of UV radiation
C) protection against food‐borne diseases
D) protection against coronary heart disease
E) protection against mutations
A) protection against malaria
The advantage to heterozygotes described in the previous question is an example of \_\_\_\_\_\_\_\_\_\_. A) unusually high mutation rate B) random genetic variation C) a silent mutation D) a major histocompatibility complex E) frequency‐dependent selection
E) frequency‐dependent selection
The Hardy‐Weinberg law states that the frequencies of alleles and genotypes remain constant
from generation to generation in a population with __________.
A) a large (infinite) number of individuals
B) random mating
C) no natural selection
D) no mutation
E) no migration between populations
F) All of the above conditions must be met.
F) All of the above conditions must be met.
In a particular population, gene A has only two alleles, A1 and A2. The frequencies of these two
alleles are known and designated p and q, respectively. What would the equilibrium frequency
of the genotype A1A2 be?
A) p2 B) q2 C) pq D) 2pq E) p2 + 2pq + q2
D) 2pq
In a particular population, gene A has only two alleles, A1 and A2. The frequencies of these two
alleles are known and you calculate the Hardy‐Weinberg equilibrium frequencies of the three
possible genotypes, A1A1, A1A2, and A2A2. The actual frequencies of these genotypes in the
population depart substantially from the equilibrium frequencies. Which of the following
processes is responsible for this departure from equilibrium frequencies?
A) genetic drift D) natural selection
B) assortative mating E) any of the above, or some combination
C) migration
E) any of the above, or some combination
Of the following, the Hardy‐Weinberg equilibrium is much more sensitive to departures from
one. Which is it?
A) infinite population size D) no natural selection
B) no mutation E) random mating
C) no migration
E) random mating
Of the two kinds of assortative mating, one leads to a reduction in the proportion of
heterozygotes in a population. Which is it?
A) positive B) negative
A) positive
Which of the following results in inbreeding?
A) negative assortative mating C) random mating
B) positive assortative mating D) abstinence
B) positive assortative mating
You maintain two monkeyflower (Mimulus guttatus) populations, one with enforced selfing, the
other (control) where outcrossing is permitted. Which of the two populations exhibits
consistently high ovule number and number of viable pollen grains per flower, generation after
generation?
A) selfed B) outcrossed
B) outcrossed
When all alleles of a gene except one are lost from a population, we say that the remaining
allele is fixed. When fixation occurs, what is the value of the inbreeding coefficient (F)?
A) 0.0 D) 0.5
B) 0.125 E) 1.0
C) 0.25
E) 1.0
