Deck 14: Species and Speciation

Question 1

Drosophila biologists often delimit species boundaries by crossing individuals from different populations.Implicit in this method is the

A)evolutionary species concept.
C)phylogenetic species concept.
B)phenetic species concept.
D)biological species concept.

Answer 1

D

Question 2

Negative epistasis is

A)only present in the homogametic sex.
B)a mechanism that explains the Dobzhansky-Muller model of reproductive isolation.
C)responsible for chromosomal rearrangements.
D)responsible for changes in ploidy.

Answer 2

B

Question 3

Which of the following is not a prezygotic isolating mechanism?

A)Habitat isolation
B)Temporal isolation
C)Hybrid inviability
D)Behavioral isolation
E)Gametic incompatibility

Answer 3

C

Question 4

If each number represents a population,the figure above illustrates an example of

A)a peripherally isolated species.
C)reproductive isolation.
B)a hybrid zone.
D)a ring species.

Question 5

Which of the following statements about changes in ploidy is true?

A)It often reduces reproductive isolation.
B)It can result in instantaneous speciation.
C)It causes coiling in snails.
D)It is less common in plants than animals.

Question 6

In the phylogeny depicted in the figure below,the P species are from the Pacific side and the C species are from the Caribbean side of the Isthmus of Panama.Which of the following is the most likely cause of speciation?

A)Sympatric speciation
B)Parapatric speciation
C)Allopatric speciation via dispersal across the Isthmus of Panama
D)Allopatric speciation via isolation when the Isthmus of Panama closed

Question 7

Host specificity of Rhagoletis pomonella reduces gene flow between the apple and hawthorn races by 4% to 6% in each generation.This is an example of

A)allopatric speciation.
C)secondary contact.
B)assortative mating.
D)resource competition.

Question 8

Hybrids with chromosomal inversions often have

A)a doubling of chromosomes.
B)superior environmental performance across a cline.
C)dysfunctional gametes.
D)speciated.

Question 9

How might secondary contact result in a cline?

A)Reproductive character displacement completes the speciation process.
B)Hybrid matings may have low fitness.
C)Reproductive isolation is partially complete and a spatial gradient of hybrids forms.
D)Reproductive isolation is incomplete and the two populations form a single species without spatial variation.

Question 10

The figure above illustrates

A)ploidy changes resulting in reproductive isolation.
B)Haldane's rule.
C)Dobzhansky-Muller incompatibility.
D)reproductive isolation through chromosomal rearrangement.

Question 11

A small population of a species invades an island where the species is not found.The population subsequently diverges from the ancestral population and becomes a new species.This is an example of

A)the dumbbell model of allopatric speciation.
B)the peripheral isolate mode of allopatric speciation.
C)sympatric speciation.
D)parapatric speciation.

Question 12

Two bird species exhibit postzygotic isolation in that half of the hybrids formed between them are sterile.If Haldane's rule applies here,then the individuals that are sterile are likely to be

A)female.
C)young.
B)male.
D)old.

Question 13

The evolutionary species concept defines a species as

A)a group that forms a lineage with a distinct evolutionary fate from other lineages.
B)phenotypically similar individuals or populations.
C)groups of actually or potentially interbreeding populations that are reproductively isolated from other such groups.
D)the smallest monophyletic group distinguished by a shared derived character.

Question 14

Resource partitioning occurs

A)when the same plants produce different seed types.
B)infrequently in sympatric speciation.
C)only in lakes.
D)when different habitat preferences result in different diets.

Question 15

Which of the following is not a postzygotic isolating mechanism?

A)Male gametes are not transferred to the female gametes.
B)Zygotes die early in embryogenesis.
C)Hybrids are inviable.
D)Hybrids are sterile.
E)Backcross hybrids are inviable.

Question 16

Allopatric speciation requires

A)complete geographic isolation.
C)overlapping distributions.
B)abutting distributions.
D)differences in phenology.

Question 17

A cline is a(n)

A)temporal gradient in the frequency of genotypes and phenotypes.
B)spatial gradient in the frequency of genotypes and phenotypes.
C)area of resource competition.
D)area of assortative mating.

Question 18

The figure above shows the penis length of two species of snails found in different populations in Japan.The pattern of variation in this trait illustrates

A)reproductive character displacement.
C)a hybrid zone.
B)allopatric speciation.
D)sympatric speciation.

Question 19

When are hybrid zones expected to disappear and complete the speciation process?

A)When hybrids are at a selective disadvantage
B)When hybrids have a selective advantage and will replace parents
C)When hybrids are found in ring species
D)When hybrids mate assortatively

Question 20

Which of the following statements describes a problem with applying the phenetic species concept?

A)One must construct a phylogenetic tree.
B)Character weighting is ambiguous.
C)Gene flow must be measured.
D)The concept only works with sexual species.

Question 21

The figure below shows the geological history of North and South America and the closing of the Isthmus of Panama.If a single species was distributed throughout the region indicated by the arrow in the left-most panel,and today is found as two separate species,one in the Atlantic Ocean and one in the Pacific,is this allopatric speciation likely to be an example of the dumbbell model or the peripheral isolate model? Why?

Question 22

The A₁ and the A₂ alleles in the diagram above illustrate

A)an ancestral polymorphism that is maintained in all current populations.
B)that a novel allele (A₂) arose only in the chimpanzee lineage.
C)an ancestral polymorphism that was lost in humans and chimpanzees, with different alleles going to fixation in each of these two species.
D)how species trees and gene trees are exactly the same.

Question 23

Which of the following does not contribute to the evidence for the out-of-Africa hypothesis?

A)The gradual divergence of Homo sapiens in different locations
B)The rapid replacement of other hominins by Homo sapiens approximately 100,000 years ago
C)Coalescence
D)The existence of greater mitochondrial diversity in Africa
E)The interbreeding of humans and Neanderthals

Question 24

The phylogeny illustrated in the figure below shows the relationships among 53 modern humans based on mitochondrial DNA.How does this phylogeny support the out-of-Africa hypothesis?

Question 25

In which model of allopatric speciation is genetic drift a larger factor,and why?

Question 26

In the past,many hominins coexisted,such as Paranthropus robustus and Paranthropus boisei.Imagine that these species were not prezygotically isolated and occasionally formed hybrids.Why might sterility or inviability of hybrids be limited to one sex? In which sex would this occur,and what pattern does this represent?

Question 27

What is the advantage of using DNA sequences from many genes to reconstruct the evolutionary history of humans?

Question 28

How can reproductive isolation in plants be mediated through pollinators?

Question 29

What are the distinguishing features of the hominin lineage?

A)Bipedalism and dentition
C)Big brains and dentition
B)Bipedalism and big brains
D)Big brains only

Question 30

Based on the figure below,is the common-language practice of referring to Chimpanzees as monkeys accurate? Are monkeys a monophyletic group?

Question 31

What do the two diagrams below illustrate,regarding human evolution?

A)A) Multiregional hypothesis; B) Out-of-Africa hypothesis
B)A) Out-of-Africa hypothesis; B) Multiregional hypothesis
C)A) Coexistence of multiple hominins throughout the evolutionary history of Homo sapiens; B) Existence of a single hominin throughout the evolutionary history of Homo sapiens
D)A) Existence of a single hominin throughout the evolutionary history of Homo sapiens; B) Coexistence of multiple hominins throughout the evolutionary history of Homo sapiens

Question 32

In the figure above,each white,horizontal box represents a separate species.Based on this figure,

A)the multiregional hypothesis is supported.
B)the out-of-Africa hypothesis is supported.
C)many hominin species coexisted for most of the evolutionary history of humans.
D)there has been only a single hominin species for most of the evolutionary history of humans.

Question 33

Suppose that we find an example of the peripheral isolate model of allopatric speciation in which a species pair results.One species is the progenitor,and one is the derivative species.How will these two species differ in geographical distribution,genetic diversity,and allele sharing?

Question 34

What was the major transition from archaic hominins to the genus Homo?

A)Increase in tooth size
C)Evolution of bipedalism
B)Increase in brain size
D)Evolution of skull ridges

Question 35

How does the evolutionary species concept differ from the phylogenetic species concept?

Question 36

If the population of the last common ancestor of humans,chimpanzees,and gorillas was very large,and humans split from chimpanzees very quickly after the gorilla lineage diverged,how might this influence the relationship between gene trees and species trees in this clade?

Question 37

In the graphs below,what do the axes represent? Which species concept is illustrated by these graphs?