Evolution: Final Flashcards
During a study session about evolution, one of your fellow students remarks, “The giraffe stretched its neck while reaching for higher leaves; its offspring inherited longer necks as a result.” Which statement would you use to correct this student’s misconception?
Characteristics acquired during an organism’s life are generally not passed on through genes.
Who was the naturalist who synthesized a concept of natural selection independently of Darwin?
Alfred Wallace
Charles Darwin was the first to propose
a mechanism for evolution that was supported by evidence
In evolutionary terms, the more closely related two different organisms are, the
more recently they shared a common ancestor.
Evolution by natural selection is based on all of the following except
variation exists within populations.
the fittest individuals tend to leave the most offspring.
there is differential reproductive success within populations.
populations tend to produce more individuals than the environment can support.
individuals must adapt to their environment.
individuals must adapt to their environment
Which statement about natural selection is most correct?
Adaptations beneficial in one habitat should generally be beneficial in all other habitats as well.
Different species that together occupy the same habitat will adapt to that habitat by undergoing the same genetic changes.
Adaptations beneficial at one time should generally be beneficial during all other times as well.
Well-adapted individuals leave more offspring, and thus contribute more to the gene pool, than poorly adapted individuals.
Natural selection is the sole means by which populations can change.
Well-adapted individuals leave more offspring, and thus contribute more to the gene pool, than poorly adapted individuals.
To observe natural selection’s effects on a population, what must be true?
One must observe more than one generation of the population.
The population must contain genetic variation.
Members of the population must increase or decrease the use of some portion of their anatomy.
A and C only
A and B only
A and B only
During drought years on the Galapagos, small, easily eaten seeds become rare leaving only large, hard-cased seeds that only birds with large beaks can eat. If a drought persists for several years, then what should one expect to result from natural selection?
Small birds gaining larger beaks by exercising their mouth parts.
Small birds mutating their beak genes with the result that later-generation offspring have larger beaks.
Small birds anticipating the long drought and eating more to gain weight and, consequently, growing larger beaks.
More small-beaked birds dying than the larger-beaked birds. The offspring produced in subsequent generations have a higher percentage of birds with large beaks.
Larger birds eating less so smaller birds can survive
During drought years on the Galapagos, small, easily eaten seeds become rare leaving only large, hard-cased seeds that only birds with large beaks can eat. If a drought persists for several years, then what should one expect to result from natural selection?
Small birds gaining larger beaks by exercising their mouth parts.
Small birds mutating their beak genes with the result that later-generation offspring have larger beaks.
Small birds anticipating the long drought and eating more to gain weight and, consequently, growing larger beaks.
More small-beaked birds dying than the larger-beaked birds. The offspring produced in subsequent generations have a higher percentage of birds with large beaks.
Larger birds eating less so smaller birds can survive
More small-beaked birds dying than the larger-beaked birds. The offspring produced in subsequent generations have a higher percentage of birds with large beaks.
Which of the following statements is not an inference of natural selection?
Subsequent generations of a population should have greater proportions of individuals that possess favorable traits.
An individual organism undergoes evolution over the course of its lifetime
Often only a fraction of offspring survive, because there is a struggle for limited resources.
Individuals whose inherited characteristics best fit them to the environment should leave more offspring.
Unequal reproductive success among its members leads a population to adapt over tim
An individual organism undergoes evolution over the course of its lifetime
genetic variation among individuals
variation among individuals caused by environmental factors
sexual reproduction
A and C only
A, B, and C
genetic variation among individuals
A biologist studied a population of squirrels for 15 years. During that time, the population was never fewer than 30 squirrels and never more than 45. Her data showed that over half of the squirrels born did not survive to reproduce, because of competition for food and predation. In a single generation, 90% of the squirrels that were born lived to reproduce, and the population increased to 80. What inferences might you make about this population?
The amount of available food may have increased
The number of predators may have decreased
The squirrel populations in subsequent generations should show greater levels of variation than previous generations because squirrels that would not have survived in the past will now survive
A and B only
A, B, and C
A and B only
Which statement best describes how the evolution of pesticide resistance occurs in a population of insects?
Individual members of the population slowly adapt to the presence of the chemical by striving to meet the new challenge
All insects exposed to the insecticide begin to use a formerly silent gene to make a new enzyme that breaks down the insecticide molecules.
Insects observe the behavior of other insects that survive pesticide application, and adjust their own behaviors to copy those of the survivors.
A number of genetically resistant pesticide survivors reproduce. The next generation of insects contains more genes from the survivors than it does from susceptible individuals.
B and D only
A number of genetically resistant pesticide survivors reproduce. The next generation of insects contains more genes from the survivors than it does from susceptible individuals.
DDT was once considered a “silver bullet” that would permanently eradicate insect pests. Today, instead, DDT is largely useless against many insects. What would need to be true for pest eradication efforts to have been successful in the long run?
Larger doses of DDT should have been applied
All habitats should have received applications of DDT at about the same time
The frequency of DDT application should have been higher.
All individual insects should have possessed genomes that made them susceptible to DDT.
DDT application should have been continual.
All individual insects should have possessed genomes that made them susceptible to DDT.
Structures as different as human arms, bat wings, and dolphin flippers contain many of the same bones, these bones having developed from the same embryonic tissues. How do biologists interpret these similarities?
by identifying the bones as being homologous
by the principle of convergent evolution
by proposing that humans, bats, and dolphins share a common ancestor
A and C only
A, B, and C
A and C only
Over evolutionary time, many cave-dwelling organisms have lost their eyes. Tapeworms have lost their digestive systems. Whales have lost their hind limbs. How can natural selection account for these losses?
Natural selection cannot account for losses, only for innovations.
It can account for these losses by the principle of use and disus
Under particular circumstances that persisted for long periods, each of these structures presented greater costs than benefits.
These organisms had the misfortune to experience harmful mutations, which caused the loss of these structures.
B and D only
Under particular circumstances that persisted for long periods, each of these structures presented greater costs than benefits.
t has been observed that organisms on islands are different from, but closely related to, similar forms found on the nearest continent. This is taken as evidence that
island forms and mainland forms descended from common ancestors.
common environments are inhabited by the same organisms.
the islands were originally part of the continent.
the island forms and mainland forms are converging.
island forms and mainland forms have identical gene pools.
island forms and mainland forms descended from common ancestors.
The theory of evolution is most accurately described as
an educated guess about how species originate
one possible explanation, among several scientific alternatives, about how species have come into existence
an opinion that some scientists hold about how living things change over time
an overarching explanation, supported by much evidence, for how populations change over time
an idea about how acquired characteristics are passed on to subsequent generations.
an overarching explanation, supported by much evidence, for how populations change over time
Which of the following is not an observation or inference on which natural selection is based?
There is heritable variation among individuals.
Poorly adapted individuals never produce offspring.
There is a struggle for limited resources, and only a fraction of offspring surviv
Individuals whose characteristics are best suited to the environment generally leave more offspring than those that are less well suite
Organisms interact with their environments.
Poorly adapted individuals never produce offspring.
Within a few weeks of treatment with the drug 3TC, a patient’s HIV population consists entirely of 3TC-resistant viruses. How can this result best be explained?
HIV has the ability to change its surface proteins and resist vaccines.
The patient must have become reinfected with 3TC-resistant viruses.
HIV began making drug-resistant versions of reverse transcriptase in response to the drug.
A few drug-resistant viruses were present at the start of treatment, and natural selection increased their frequency.
The drug caused the HIV RNA to chang
A few drug-resistant viruses were present at the start of treatment, and natural selection increased their frequency.
The smallest biological unit that can evolve over time is
a cell.
an individual organism.
a population.
a species.
a population.
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 (a), 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 most reasonable conclusion that can be drawn from the fact that the frequency of the recessive trait (a) has not changed over time?
The population is undergoing genetic drift.
The two phenotypes are about equally adaptive under laboratory conditions.
The genotype AA is lethal.
There has been a high rate of mutation of allele A to allele
There has been sexual selection favoring allele
The two phenotypes are about equally adaptive under laboratory conditions.
All of the following are criteria for maintaining Hardy-Weinberg equilibrium involving two alleles except
the frequency of all genotypes must be equal.
there should be no natural selection.
matings must be random.
populations must be larg
gene flow from other populations must be zero.
the frequency of all genotypes must be equal.
n 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?
3
9
30
42
49
49
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?
3
9
21
42
49
42
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?
- 20
- 32
- 42
- 80
Genotype frequency cannot be determined from the information provide
0.32
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?
- 00
- 75
- 50
- 25
- 10
0.50
Most copies of harmful recessive alleles in a sexual species are carried by individuals that are
haploid
polymorphic
homozygous for the allele
heterozygous for the allele
B and C
heterozygous for the allele
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. What is the frequency of the A allele?
- 001
- 002
- 100
- 400
- 600
0.400
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. What is the frequency of the B allele?
- 001
- 002
- 100
- 400
- 600
0.600
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. What percentage of the population has type O blood?
0
10
24
48
60
0
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. 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?
100
960
1,920
2,000
2,400
1,920
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 (the recessive allele) for this population?
- 36
- 60
- 64
- 75
- 80
0.80
Which of the following is not a requirement for maintenance of Hardy-Weinberg equilibrium?
an increasing mutation rate
random mating
large population size
no migration
no natural selection
an increasing mutation rate
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,
the allele is neutral.
the allele mutates readily.
random processes have changed allelic frequencies.
there is no sexual selection.
the allele reduces fitness.
the allele reduces fitness.
Through time, the movement of people on Earth has steadily increased. This has altered the course of human evolution by increasing
nonrandom reproduction.
geographic isolation.
genetic drift.
mutations.
gene flow.
gene flow.
Gene flow is a concept best used to describe an exchange between
species.
males and females.
populations.
individuals.
chromosomes.
populations
The Darwinian fitness of an individual is measured by
the number of its offspring that survive to reproduce
the number of supergenes in the genotype
the number of mates it attracts.
its physical strength.
how long it lives.
the number of its offspring that survive to reproduce
If a phenotypic polymorphism lacks a genetic component, then
the environment cannot affect its abundance
natural selection cannot act upon it to make a population better adapted over the course of generations.
it cannot affect an individual’s ability to survive
it must exhibit quantitative variation.
all of the above
natural selection cannot act upon it to make a population better adapted over the course of generations.
