Deck 16: Mechanisms of Speciation

Question 1

Organisms such as prokaryotes (bacteria and archaea)―along with some eukaryotes―reproduce asexually.In the case of bacteria and archaea in particular,which exchange DNA but do not reproduce utilizing conventional sexual reproduction,the BEST way in which to define species is with ________.

A) the morphospecies concept
B) the phylogenetic species concept
C) the biological species concept
D) an ecological species concept

Answer 1

D

Question 2

It now seems clear that the strongest factor in speciation events is ________.

A) genetic drift
B) sexual selection
C) natural selection
D) the bottleneck effect

Answer 2

C

Question 3

Which of the following models of speciation hinges on a physical barrier which prevents gene flow between populations?

A) dispersive allopatric
B) dispersive sympatric
C) vicariant allopatric
D) vicariant sympatric
E) Both A and C.

Answer 3

E

Question 4

Early classification systems from Aristotle to Linneaus would have been most like what we now call ________.

A) the morphospecies concept
B) the phylogenetic species concept
C) the biological species concept
D) the ecological species concept

Question 5

The model of speciation that hinges on a physical barrier preventing gene flow is ________ speciation.

Question 6

The classical hypothesis of speciation is comprised of a three-step process.What are the three steps?

Question 7

Hybridization between populations upon secondary contact may result in ________.

A) reinforcement of the two original species by way of pre- or post-zygotic isolating mechanisms
B) the creation of one or more new species as hybrids between the two parental species
C) the creation of a hybrid lineage that has higher fitness than either of the parental species
D) All of the above are possible.
E) None of the above are possible.

Question 8

There are two closely related populations of squirrels living in the Grand Canyon area―one lives on the north rim,the other lives on the south rim.Speciation in these squirrels BEST fits which model?

A) dispersive allopatric speciation
B) dispersive sympatric speciation
C) vicariant allopatric speciation
D) vicariant sympatric speciation

Question 9

The species concept defined as a group of organisms that are capable of interbreeding to produce fertile offspring is ________.

A) the morphospecies concept
B) the phylogenetic species concept
C) the biological species concept
D) the ecological species concept

Question 10

Research on speciation of Hawaiian crickets,shown in the accompanying figure,has led researchers to conclude that ________.

A) these cricket species have diverged by a mechanism known as assortative mating
B) females of different species have strong preferences for the singing pulse rate of the males of their own species
C) female preference for male singing pulse rate is genetically linked to the combination of genes regulating the singing pulse rate of males
D) All of the above are accurate.

Question 11

Groups of organisms that cannot be distinguished morphologically but have no gene flow between them,and are indeed evolutionary independent units,are known as ________ species.

Question 12

A disadvantage of the morphospecies concept is ________.

A) it can be difficult to apply to organisms with small, difficult to distinguish features
B) species definitions may become arbitrary if the concept is not applied carefully
C) species definitions applied by different researchers may not be comparable
D) All of these are potential problems with this species concept.

Question 13

Your textbook authors make the claim that "sympatric species with matching chromosome numbers are rare." Why is this?

A) because allopatric speciation is far more common
B) because sympatric speciation has only been hypothesized but not documented
C) because coexisting populations need a boundary to gene flow before divergence can occur, and differences in chromosome numbers provide this
D) because macroevolution is just a theory

Question 14

The species concept based on careful analysis of the anatomical details of the specimen in question is ________.

A) the morphospecies concept
B) the phylogenetic species concept
C) the biological species concept
D) the ecological species concept

Question 15

Isolating mechanisms leading to speciation have been documented by ________.

A) geographic isolation
B) polyploidy
C) temporal isolation
D) a mutation in a single gene
E) All of the above.

Question 16

Factors such as behavioral,temporal,or ecological isolation mechanisms that prevent two closely related sympatric populations from interbreeding can be grouped together and classified as ________.

A) prezygotic isolating mechanisms
B) postzygotic isolating mechanisms
C) polyploidy hybrid speciation
D) adaptive radiation

Question 17

The species concept based on analysis of character states that indicate the smallest monophyletic group is ________.

A) the morphospecies concept
B) the phylogenetic species concept
C) the biological species concept
D) the ecological species concept

Question 18

The accompanying figure most closely represents speciation by ________.

A) natural selection
B) reinforcement
C) hybridization
D) polyploidy

Question 19

From an ecological perspective,the dispersal of fruit flies (Drosophila)on the Hawaiian islands,which has resulted in speciation,is BEST termed ________.

A) vicariance
B) reinforcement
C) hybridization
D) adaptive radiation

Question 20

The species concept that relies most heavily on the criterion that species are evolutionarily independent units that are isolated by gene flow is ________.

A) the morphospecies concept
B) the phylogenetic species concept
C) the biological species concept
D) This criterion is common to all of these concepts.

Question 21

Selection that reduces the frequency of hybridization and/or the fitness of hybrids between populations following secondary contact is termed ________.

Question 22

Speciation events that occur when the geographic ranges of the populations involved overlap are termed ________.

Question 23

Suppose a bird population that qualifies as a single species according to the Biological Species Concept (BSC)is separated into two isolated populations by an advancing glacier during an Ice Age.What will happen when the glacier retreats,allowing the two populations to come back together (secondary contact)? Be sure to account for all possible outcomes.

Question 24

Geographic isolation of populations can generally come about in two ways.What are they?

Question 25

Species divergence due to mating behavior and sexual selection,as has been documented in the Hawaiian crickets,is termed ________.[two words]

Question 26

Speciation through hybridization may or may not involve a change in the chromosome number of the hybrids.Name and explain,using examples,how speciation events in both of these cases has been documented.

Question 27

Each of the species concepts (morphospecies,biological,and phylogenetic)have strengths and weaknesses.Compare and contrast all three,and evaluate them for their relative usefulness.

Question 28

Relative to chromosome numbers,hybridization can produce speciation in two ways.What are they?