Deck 5: Evolution and Gene Frequencies

Question 1

The work of Peter and Rosemary Grant,on morphological changes in the bills of Galápagos finches,shows that evolution can be

A)convergent.
B)rapid.
C)divergent.
D)gradual.
E)sympatric.

Answer 1

B

Question 2

Genetic drift is most likely to have noticeable effects in:

A)large populations where migration occurs regularly.
B)small populations where migration occurs regularly.
C)large populations where mutation occurs regularly.
D)small, isolated populations.
E)small populations where mutation and migration occur regularly.

Answer 2

D

Question 3

The unusual gene frequencies of the Dunker population of eastern Pennsylvania are due to this phenomenon,which is seen frequently when small groups with unrepresentative gene frequencies break off from a larger population.

A)unidirectional selection
B)population bottleneck
C)neutral allele
D)disruptive selection
E)founder effect

Answer 3

E

Question 4

__________ selection may occur when a phenotype at one extreme of a distribution is at a disadvantage.

A)Deleterious
B)Directional
C)Disruptive
D)Discretional
E)Stabilizing

Question 5

One of the assumptions of the Hardy-Weinberg theorem is that

A)the size of the population is small.
B)gene frequencies change by chance alone.
C)migration into and out of the population occurs regularly.
D)mating within the population is random.
E)mutations occur regularly.

Question 6

Natural selection acts on individual __________,not on individual genes.

A)phenotypes
B)karyotypes
C)genotypes
D)chromosomes

Question 7

A form of natural selection that occurs when both phenotypic extremes are selected against is __________ selection.

A)directional
B)deleterious
C)discretionary
D)disruptive
E)stabilizing

Question 8

When individuals of an intermediate phenotype are at a relative disadvantage within the population,__________ selection is occurring.

A)directional
B)deleterious
C)stabilizing
D)disruptive
E)discretionary

Question 9

Which of the following is not an assumption of the Hardy-Weinberg theorem?

A)The population size must be large.
B)Sexual reproduction within the population must be random.
C)No migration is occurring in or out of the population.
D)Mutations are not occurring or mutational equilibrium has been reached.
E)Natural selection is acting on the population.

Question 10

Vertebrate hemoglobin and myoglobin are thought to have arisen from a common ancestral molecule due to __________ and subsequent modification.

A)gene duplication
B)multiple replication of DNA
C)crossing over
D)aneuploidy
E)multiple transcription of mRNA

Question 11

An excellent example of directional selection is

A)aposematic coloration.
B)Mullerian mimicry.
C)change in the coloration of the peppered moth during the Industrial Revolution.
D)cryptic coloration.
E)that Limulus has remained relatively unchanged over millions of years.

Question 12

An excellent example of stabilizing selection is the external body form of a:

A)horseshoe crab.
B)dendrobatid Darwin's finch.
C)peppered moth.
D)modern horse.

Question 13

One of the assumptions of the Hardy-Weinberg theorem is that

A)mating within the population is nonrandom.
B)the size of the population is small.
C)gene frequencies change by chance alone.
D)migration into and out of the population occurs regularly.
E)mutations must not occur or a mutational equilibrium must exist.

Question 14

The total genetic makeup of a population is the

A)genotype.
B)gene pool.
C)phenotype.
D)karyotype.
E)RNA pool.

Question 15

When chance events influence the frequency of alleles within a population,__________ has occurred.

A)preadaptation
B)genetic drift
C)adaptation
D)adaptive radiation
E)genetic radiation

Question 16

The study of the genetic events that occur in a gene pool is

A)geneology.
B)molecular biology.
C)population genetics.
D)phenology.
E)molecular genetics.

Question 17

When natural selection favors certain phenotypes in a population,the population is responding to:

A)selection pressure.
B)peer pressure.
C)teleology.
D)equilibrium pressure.
E)genetic drift.

Question 18

When the Hardy-Weinberg equilibrium is achieved,evolution

A)occurs slowly and at a constant rate.
B)occurs rapidly and at a constant rate.
C)occurs in "bursts."
D)does not occur.
E)alternates between a constant rate and "bursts," but never ceases.

Question 19

A group of individuals of the same species that occupy a given area at the same time and share a common set of genes is the definition of a/an

A)organism.
B)ecosystem.
C)community.
D)population.
E)gene pool.

Question 20

Assuming the conditions set by Hardy-Weinberg equilibrium,if the frequency of phenotype A is 96%,the frequency of A in the next generation would be

A)8%.
B)16%.
C)96%.
D)48%.
E)Hardy-Weinberg theory cannot predict the frequency of a phenotype, only a genotype.

Question 21

Geographic isolation can lead to speciation,and when it does,the speciation is called

A)allelopathic.
B)parapatric.
C)allopatric.
D)parapathetic.
E)sympatric.

Question 22

Mutational equilibrium exists when

A)only neutral mutations are occurring.
B)only positive mutations are occurring.
C)only negative mutations are occurring.
D)mutations from wild-type to mutant are balanced by mutations from mutant to wild-type.
E)mutation pressure becomes higher than the influence of genetic drift.

Question 23

A requirement for speciation is that subpopulations

A)continue to interact with one another.
B)become reproductively isolated from one another.
C)never experience mutations.
D)exhibit balanced polymorphism.

Question 24

Parapatric speciation may occur among small,local populations called

A)demes.
B)clines.
C)cohorts.
D)communities.
E)pools.

Question 25

In the punctuated equilibrium model of evolution,long periods of stasis are characterized by __________ selection.

A)directional
B)disruptive
C)deleterious
D)stabilizing
E)neutral

Question 26

_____ speciation in a population of animals is believed to occur extremely rarely.

A)Sympatric
B)Parapatric
C)Allopatric
D)Small
E)Reproductively isolated

Question 27

Darwin perceived evolutionary change as occurring gradually over millions of years; this has been the traditional interpretation of the pace of evolution and is referred to as

A)punctuated equilibrium.
B)gradualistic equilibrium.
C)phyletic gradualism.
D)phyletic punctuation.
E)the Hardy-Weinberg equilibrium.

Question 28

Mutations of an organism's DNA are

A)always harmful to the organism.
B)extremely rare in natural populations.
C)are always directed toward the good of the individual.
D)accumulated in the somatic cells through life and passed to offspring.
E)sometimes silent and carried through generations with no ill effects.

Question 29

In the punctuated equilibrium model of evolution,periods of evolution are:

A)long, with gradual change
B)long, with rapid change
C)long, with fluctuating change
D)short, with slow change
E)short, with rapid change

Question 30

Overhunting of the elephant seal dramatically reduced its numbers in the 1800s.The population has since increased,but due to the _____________ effect its genetic diversity is still very low.

A)bottleneck
B)neutral
C)disruptive
D)founder
E)reduction

Question 31

In a human population carrying the gene for sickle-cell anemia,and exposed to malaria,several genotypes persist in a

A)sex-linked trait.
B)genetic drift.
C)disruptive selection.
D)the bottleneck effect.
E)balanced polymorphism.

Question 32

The biological definition of a __________ is a group of populations in which genes are actually,or potentially,exchanged through inter-breeding.

A)species
B)cohort
C)cline
D)subspecies
E)community