Species And Speciation Ch 17 & 18

Front 1

Coyne and Orr’s studies of reproductive isolation and genetic divergence between pairs of Drosophila populations and species discovered that
a. reproductively isolation requires a large degree of genetic distance.
b. prezygotic isolation and postzygotic isolation evolve at the same rate.
c. among recently diverged populations, premating isolation tends to be stronger than postmating isolation.
d. speciation is not a gradual process.
e. the time required for full reproductive isolation is not highly variable.

Back 1

c. among recently diverged populations, premating isolation tends to be stronger than postmating isolation.

Front 2

Dobzhansky proposed that distinct populations have coadapted gene pools. A byproduct of this phenomenon is
a. the absence of reproductive isolation.
b. known as Haldane’s rule.
c. vicariance.
d. heterosis.
e. F2 breakdown.

Back 2

e. F2 breakdown.

Front 3

The notion that a species is a single lineage of populations or organisms that maintains a separate identity from other lineages is called the _______ species concept.
a. phylogenetic
b. recognition
c. cohesion
d. biological
e. evolutionary

Back 3

e. evolutionary

Front 4

Epistatic interactions that underlie postzygotic isolation are called _______ incompatibilities.
a. Fisher-Wright
b. Darwinian
c. Stebbins-Mayr
d. Dobzhansky-Muller
e. Gould-Lewontin

Back 4

d. Dobzhansky-Muller

Front 5

Which of the following is not one of the possible fates of a hybrid zone?
a. Persistence for an indefinite period of time
b. Full reproductive isolation between populations
c. Merging of the semispecies into a single species
d. Extinction of all populations due to hybridization
e. Evolution of some hybrids into a third species

Back 5

d. Extinction of all populations due to hybridization

Front 6

The biological species concept has been widely adopted, but it also has some practical difficulties. Which of the following is not one of these difficulties?
a. The concept is poorly defined.
b. The concept cannot be applied to extinct species.
c. Many populations are allopatric.
d. The concept does not apply to clonal organisms.
e. Testing reproductive isolation in the lab is not always feasible.

Back 6

a. The concept is poorly defined.

Front 7

The difference between primary and secondary hybrid zones is that primary hybrid zones _______, while secondary hybrid zones _______.
a. involve prezygotic isolation; involve postzygotic isolation
b. are formed in situ as natural selection alters allele frequencies in continuously distributed populations; arise when two formerly allopatric species come in contact again
c. predate speciation; postdate speciation
d. involve only a pair of species; involve more than two species
e. arise when two formerly allopatric species come in contact again; are formed in situ as natural selection alters allele frequencies in continuously distributed populations

Back 7

b. are formed in situ as natural selection alters allele frequencies in continuously distributed populations; arise when two formerly allopatric species come in contact again

Front 8

Refer to the figure below depicting a gene tree for populations of the crested auklet (Aethia cristatella) and the least auklet (A. pusilla). Sequences of the crested auklet are labeled with a blue C, while sequences of the least auklet are labeled with a red L. A vertical red line indicates the timing of speciation. What phenomenon does this figure depict?
a. Secondary contact
b. Incomplete lineage sorting
c. A hybrid zone
d. Behavioral isolation
e. Long-branch attraction

Back 8

b. Incomplete lineage sorting

Front 9

Refer to the figure below. The genomes of two species of jimsonweed (Datura stramonium and D. discolor) differ by multiple translocations, and F1 hybrids of these two species have distinctive chromosomal pairings. An implication of this rearrangement is that
a. F1 plants will be large in size.
b. aneuploidy in the offspring of F1 individuals is likely.
c. F1 plants will have higher desiccation tolerance.
d. the fitness of F1 plants will not be affected.
e. there is little minimal postzygotic reproductive isolation for these species.

Back 9

b. aneuploidy in the offspring of F1 individuals is likely.

Front 10

In many groups of insects, the genitalia of related species differ in morphology, such as these three Drosophila species below.
One explanation is that this trait is not highly constrained. Another explanation involves
a. ecological specialization.
b. sex-linked genes.
c. Dollo’s law.
d. the “lock and key” hypothesis.
e. Haldane’s rule.

Back 10

d. the “lock and key” hypothesis.

Front 11

Which of the following terms refers to a variance of a species that is associated with a particular type of habitat?
a. Superspecies
b. Polytypic species
c. Race
d. Ecotype
e. Sister species

Back 11

d. Ecotype

Front 12

Introgression studies indicate that many (>100) genes may cause hybrid male sterility among closely related Drosophila species. However, most of these genes do not produce any ill effects in natural populations because
a. male sterility alleles are dominant.
b. many incompatibilities are due to epistatic interactions.
c. mutation rates are several orders of magnitude larger in the lab.
d. all of the species tested are allopatric.
e. of genetic drift.

Back 12

b. many incompatibilities are due to epistatic interactions.

Front 13

According to the biological species concept, speciation consists of the evolution of biological barriers to gene flow. The most important distinction is between _______ and _______ barriers.
a. male; female
b. sexual selection; natural selection
c. temporal; spatial
d. ecological; evolutionary
e. prezygotic; postzygotic

Back 13

e. prezygotic; postzygotic

Front 14

Which of the following ideas is central to the biological species concept?
a. Vicariance
b. Sexual selection
c. Divergent phenotypes
d. Reproductive isolation
e. Distinct lineages

Back 14

d. Reproductive isolation

Front 15

Two populations become reproductively isolated from each other. Initially they shared many of the same gene lineages, but over time different lineages are lost in each population and eventually these populations may speciate. Which of the following describes how genetic lineages change over time in this hypothetical scenario?
a. Paraphyly → polyphyly → monophyly
b. Monophyly → paraphyly → polyphyly
c. Monophyly → polyphyly → paraphyly
d. Paraphyly → monophyly → polyphyly
e. Polyphyly → paraphyly → monophyly

Back 15

e. Polyphyly → paraphyly → monophyly

Front 16

Which of the following is a definition of allopatric speciation?
a. Evolution of reproductive isolation between spatially distinct populations that are connected via small amounts of gene flow
b. Divergence of a small population from a widely distributed ancestral form
c. Evolution of genetic reproductive barriers between populations that are geographically separated
d. Evolution of genetic reproductive barriers within a single, initially panmictic population
e. Speciation due to divergence of allozymes

Back 16

c. Evolution of genetic reproductive barriers between populations that are geographically separated

Front 17

Why is it difficult to measure speciation rates over evolutionary time scales?
a. Speciation by polyploidy can be very rapid.
b. Generation times can be long.
c. High diversification rates can be due either to high rates of speciation or to low rates of extinction.
d. Ecological diversification contributes to speciation.
e. Genetic variation between populations is required.

Back 17

c. High diversification rates can be due either to high rates of speciation or to low rates of extinction.

Front 18

Which of the following observations does not provide evidence that sexual selection can be an important cause of speciation?
a. There is population-level divergence in male “whine” calls in the South American frog Physalaemus petersi.
b. Female crickets respond to songs that have a pulse rate similar to that of their own species.
c. In cichlid fish the color of males acts as a reproductive barrier between species.
d. Groups of birds with promiscuous mating systems have higher diversity than sister clades have.
e. In many species, recombination rates differ for males and females.

Back 18

e. In many species, recombination rates differ for males and females.

Front 19

You collect individuals from different allopatric populations of the leaf beetle Neochlamisus bebbianae. Back in the laboratory, you conduct mate-choice experiments to assess levels of reproductive isolation among beetles from different populations. Assuming that ecological speciation occurred in the wild, what patterns should you expect?
a. No reproductive isolation will be observed.
b. Reproductive isolation is independent of habitat type.
c. Populations that share similar habitats will be more reproductively isolated.
d. Populations that share similar habitats will be less reproductively isolated.
e. Complete reproductive isolation will exist among all populations.

Back 19

d. Populations that share similar habitats will be less reproductively isolated.

Front 20

Which mode of speciation involves intermediate levels of gene flow?
a. Allopatric speciation
b. Sympatric speciation
c. Parapatric speciation
d. Founder effect speciation
e. Cytological divergence

Back 20

c. Parapatric speciation

Front 21

Most models of sympatric speciation postulate the existence of
a. extinction and recolonization of local populations.
b. geographical barriers between populations.
c. disruptive selection based on resource use.
d. high levels of recombination between loci.
e. unequal numbers of males and females

Back 21

c. disruptive selection based on resource use.

Front 22

Refer to the figure below showing the hybrid origin of diploid species of sunflowers. The sunflower phylogeny indicates that
a. only sister species can hybridize.
b. hybridization between the sunflower species Helianthus annuus and H. petiolaris has given rise to three distinct species.
c. H. praecox, H. debilis, and H. exilis are monophyletic.
d. hybrid speciation rarely results in ecological specialization.
e. H. niveus subspecies are monophyletic.

Back 22

b. hybridization between the sunflower species Helianthus annuus and H. petiolaris has given rise to three distinct species.

Front 23

What enables Dobzhansky-Muller incompatibilities to become established?
a. Neither of two allopatric populations passes through a stage at which inferior genotypes are observed
b. High mutation rates
c. Large population sizes
d. Recombination
e. Chromosomal inversions

Back 23

a. Neither of two allopatric populations passes through a stage at which inferior genotypes are observed

Front 24

How do rates of morphological evolution differ for phyletic gradualism and punctuated equilibrium models of evolution?
a. Rates of morphological evolution are faster with phyletic gradualism.
b. Rates of morphological evolution are faster with punctuated equilibrium.
c. In the gradual model, faster rates occur with speciation.
d. In the punctuated equilibrium model, faster rates occur with speciation.
e. None of the above; rates of morphological evolution are constant and equal for both models.

Back 24

d. In the punctuated equilibrium model, faster rates occur with speciation.

Front 25

Hawthorn trees were the ancestral hosts of the apple maggot fly (Rhagoletis pomonella). In the last 150 years, however, cultivated apples have become a host for some populations of R. pomonella. Development times differ for populations that prefer different host plants, and emergence time is an important ecological trait. Allele frequencies vary by latitude and host plant. Which of the following details weakens the argument that this is an example of sympatric speciation?
a. Allele frequencies are clinal.
b. The host-shift occurred in the recent evolutionary past.
c. R. pomonella females lay eggs inside of fruits.
d. The divergence in development time for the hawthorn-feeding populations occurred in Mexico, not the northeastern United States.
e. There is little gene flow between hawthorn-feeding and apple-feeding populations.

Back 25

d. The divergence in development time for the hawthorn-feeding populations occurred in Mexico, not the northeastern United States.

Front 26

Which of the following is evidence for allopatric speciation among finch species of the Galápagos Islands?
a. Resource levels vary from year to year.
b. Beak sizes are adaptations to seed sizes.
c. Pairs of sister species can be found on adjacent islands.
d. No pairs of sister species appear on the same island.
e. Many different species have been found on the islands.

Back 26

d. No pairs of sister species appear on the same island.

Front 27

Which of the following statements about peripatric speciation is true?
a. It requires high levels of gene flow between populations.
b. There is substantial evidence that this type of speciation occurs frequently in nature.
c. It requires large population sizes.
d. It can explain the sudden appearance in the fossil record of new species.
e. It does not involve any peak shifts.

Back 27

d. It can explain the sudden appearance in the fossil record of new species

Front 28

The central problem of speciation is how two different populations can be formed without-out intermediates. Solutions to this problem are called modes of speciation. The major criteria used to distinguish modes of speciation are
a. the timing of barriers to gene flow and the geographic origin of these barriers.
b. population sizes and the evolutionary causes of barriers to gene flow.
c. the timing of barriers to gene flow, the geographic origin of these barriers, and the genetic bases of the barriers.
d. diversification rates.
e. the geographic origin of barriers to gene flow, the genetic bases of these barriers, and the evolutionary causes of barriers.

Back 28

e. the geographic origin of barriers to gene flow, the genetic bases of these barriers, and the evolutionary causes of barriers.

Front 29

Most examples of polyploidy speciation involve
a. plants.
b. mammals.
c. arthropods.
d. prokaryotes.
e. fungi.

Back 29

a. plants.

Front 30

Why does reinforcement involve a strengthening of prezygotic, rather than postzygotic, isolation?
a. The rewards of postzygotic isolation are always much smaller than those of prezygotic isolation.
b. Reinforcement occurs only rarely.
c. Posyzygotic isolation has only a minimal evolutionary impact.
d. Strengthening postzygotic isolation would require that alleles that reduce fitness increase in frequency.
e. Assortative mating is uncommon.

Back 30

d. Strengthening postzygotic isolation would require that alleles that reduce fitness increase in frequency.