Chapter 22

Front 1

6. The model that assumes that evolution proceeds with slow successive change in a given evolutionary line is referred to as
A. successive descent model.
B. punctuated equilibrium.
C. gradualism.
D. the allopatric model.
E. the sympatric model.

Back 1

C. gradualism.

Front 2

7. The type of speciation that results in the formation of separate species as a result of geographic isolation is called ____________ speciation.
A. gradual
B. sympatric
C. allopatric
D. sexual
E. adaptive

Back 2

C. allopatric

Front 3

8. When species are kept separate by preventing the formation of hybrid zygotes, the mechanism that keeps the species separate is known as a _____________ isolating mechanism.
A. hybridization
B. postzygotic
C. prezygotic
D. adaptive
E. differential

Back 3

C. prezygotic

Front 4

9. A type of isolating mechanism that leads to reproductive isolation after a hybrid zygote has formed is called a _____________ isolating mechanism.
A. hybridization
B. postzygotic
C. prezygotic
D. adaptive
E. differential

Back 4

B. postzygotic

Front 5

10. Which isolating mechanism is postzygotic?
A. hybrid sterility
B. behavioral isolation
C. ecological isolation
D. mechanical isolation
E. temporal isolation

Back 5

A. hybrid sterility

Front 6

11. Evolution acts at the level of the
A. ecosystem.
B. population.
C. species.
D. community.

Back 6

B. population.

Front 7

12. Hybridization regularly occurs between three species of Darwin’s finches on Daphne Major, but the finches are still considered different species because
A. they have different fitnesses.
B. they are reproductively isolated.
C. they are mechanically isolated.
D. they occupy different niches.

Back 7

D. they occupy different niches.

Front 8

13. According to the Biological Species Concept, two groups of organisms that are unable to form fertile, viable hybrids are considered to be different
A. races.
B. species.
C. kingdoms.
D. hybrids.
E. cohabitants.

Back 8

B. species.

Front 9

14. In 1938, scientists found a population of coelacanths in the Indian Ocean. This fish species is considered a “living fossil” and appears not to have changed morphologically for 80 million years. This discovery supports the ___________ model of evolution.
A. gradualism
B. punctuated equilibrium
C. adaptation
D. natural selection
E. common descent

Back 9

B. punctuated equilibrium

Front 10

16. If populations within the same area split into sopecies, the process is known as
A. sympatric speciation.
B. allopatric speciation.
C. racial speciation.
D. ecotypical speciation.
E. reproductive speciation.

Back 10

A. sympatric speciation.

Front 11

17. If species are competing for the same resource, one species is likely to go extinct through competitive exclusion, or natural selection will drive the evolution of
A. prezygotic isolating mechanisms.
B. hybrids.
C. character displacement.
D. polyploid individuals.

Back 11

C. character displacement.

Front 12

18. Scientists found that different beak shapes lead to different mating songs in Darwin's finches. This result best supports which hypothesis?
A. Darwin's finches are not different species according to the Biological Species Concept.
B. Adaptation to different food sources indirectly led to behavioral isolation in Darwin's finches.
C. Behavioral isolation in Darwin's finches is unrelated to beak shape.
D. Adaptation to different food sources likely occurred after reproductive isolation in Darwin's finches.

Back 12

B. Adaptation to different food sources indirectly led to behavioral isolation in Darwin's finches.

Front 13

19. Once species have formed, they keep their identity by
A. developmental differences.
B. genetic blocks.
C. isolating mechanisms.
D. somatic mutations.
E. structural modifications.

Back 13

C. isolating mechanisms.

Front 14

20. Many species might coexist in a particular environment by occupying ecological
A. biomes.
B. niches.
C. territories.
D. domains.
E. ranges.

Back 14

B. niches.

Front 15

21. Males of several marsupial species have forked penises that are incompatible with female placental mammals. This is an example of what type of isolating mechanism?
A. ecological isolation
B. temporal isolation
C. mechanical incompatibility
D. hybrid sterility
E. prevention of gamete fusion

Back 15

C. mechanical incompatibility

Front 16

22. Prezygotic mechanisms lead to reproductive isolation by preventing the formation of
A. mating pairs.
B. fertile eggs.
C. fertile sperm or pollen cells.
D. somatic cells.
E. hybrid zygotes.

Back 16

E. hybrid zygotes.

Front 17

23. In the southeastern U.S., two species of wild lettuce (Lactuca) do not usually form hybrids, because they bloom at different seasons. The means of isolation appears to be
A. postzygotic and behavioral.
B. prezygotic and temporal.
C. prezygotic and geographical.
D. prezygotic and mechanical.
E. postzygotic and ecological.

Back 17

B. prezygotic and temporal.

Front 18

24. The hundreds of species of Drosophila in Hawaii exhibit different mating rituals. This isolating mechanism is
A. prezygotic and behavioral.
B. prezygotic and temporal.
C. prezygotic and geographical.
D. postzygotic and mechanical.
E. prezygotic and ecological.

Back 18

A. prezygotic and behavioral.

Front 19

26. Scientists studying a group of related bird species on an island archipelago discover that these species are always more closely related to each other within an island than they are between any two islands. The most likely explanation for this result is that
A. each bird species evolved different adaptations in allopatry and then colonized the other islands.
B. one bird species colonized each island and then evolved into distinct species on that island through character displacement.
C. each bird species colonized one island and then no further speciation occurred.
D. many ancestral bird species colonized each island.

Back 19

B. one bird species colonized each island and then evolved into distinct species on that island through character displacement.

Front 20

27. Very rapid speciation occurred when cichlid fishes were isolated in Lake Victoria. Widespread extinction was dramatically seen when
A. artificial selection stopped.
B. predatory fish were added.
C. hybridization stopped.
D. fishing was prohibited.
E. insect larvae stocks were depleted.

Back 20

B. predatory fish were added.

Front 21

28. Species formation among alpine buttercups in New Zealand was promoted by
A. mechanical isolation.
B. gametic isolation.
C. periodic isolation by glaciation.
D. temporal isolation.
E. geographical isolation.

Back 21

C. periodic isolation by glaciation.

Front 22

29. Studies of snapping shrimp on either side of the Isthmus of Panama have shown that each Caribbean shrimp species is more closely related to a Pacific shrimp species than it is to any other Caribbean shrimp species. The most likely explanation for this result is
A. snapping shrimp in the Caribbean and the Pacific were never part of the same population.
B. snapping shrimp species were completely diverged prior to the formation of the Isthmus of Panama.
C. the formation of the Isthmus of Panama had no effect on speciation in snapping shrimp.
D. snapping shrimp species diverged after the formation of the Isthmus of Panama.

Back 22

D. snapping shrimp species diverged after the formation of the Isthmus of Panama.

Front 23

30. The sunflower species Helianthus anomalus is thought to have been formed by hybridization between the sunflower species H. petiolaris and H. annuus because it contains genetic material of both parental species. H. anomalus is most likely an example of instantaneous speciation through
A. allopolyploidy.
B. autopolyploidy.
C. parthenogenesis.
D. hybrid sterility.

Back 23

A. allopolyploidy.

Front 24

32. Punctuated equilibrium proposed by Eldredge and Gould in 1972 is an evolutionary process that involves
A. gradual change observable in the fossil record with very little, if any, stasis.
B. "spurts" of change observable in the fossil record followed by periods of stasis.
C. gradual change observable in the fossil record followed by periods of stasis.
D. "spurts" of change observable in the fossil record with very little if any stasis.
E. gradual change observable in the fossil record followed by periods of no change at all.

Back 24

B. "spurts" of change observable in the fossil record followed by periods of stasis.

Front 25

35. A virgin pine forest covers a valley, and one of the inhabitants is a red squirrel species. A large volcanic eruption occurs and separates the valley with a huge lava flow that the squirrels cannot cross, thus producing two isolated populations of squirrels. What change needs to occur for the two populations of squirrels to become separate species?
A. The two squirrel populations must eat distinct species of plants.
B. The area that the squirrel populations occupy changes so that the squirrel populations exist in distinct habitats.
C. The fur color of the two squirrel populations must become distinct.
D. The two squirrel populations select mates using the same sexual behavior.
E. The two squirrel populations become reproductively isolated.

Back 25

E. The two squirrel populations become reproductively isolated.

Front 26

36. Two bird species have different mating calls, occupy different habitats in nature, and when they hybridize, the hybrids are infertile. Which isolating mechanisms maintain these species?
A. ecological isolation, behavioral isolation, and hybrid sterility
B. mechanical isolation, hybrid sterility, geographical isolation
C. ecological isolation, mechanical isolation, hybrid sterility
D. geographical isolation, temporal isolation, behavioral isolation

Back 26

A. ecological isolation, behavioral isolation, and hybrid sterility

Front 27

37. Adaptive radiation is best described as the
A. existence of groups of closely related species recently evolved from a common ancestor.
B. existence of groups of distantly related species recently evolved from a common ancestor.
C. existence of groups of closely related species recently evolved from different ancestors through hybridization.
D. existence of individuals of closely related species that originated in different areas within diverse habitats, but that have rejoined as a single species.

Back 27

A. existence of groups of closely related species recently evolved from a common ancestor.

Front 28

38. The most common mechanism for sympatric speciation in plants is
A. polyploidy.
B. geographic isolation.
C. spontaneous mutation.
D. punctuated equilibrium.
E. disruptive selection.

Back 28

A. polyploidy.

Front 29

39. Lake Victoria is famous for its variety of cichlid fishes. In fact, they offer the most diverse assembly of vertebrates presently known to science. One trait that scientists have focused on as one possible reason for their adaptability is
A. a second set of scales that lie beneath the top outermost scales.
B. a second set of jaws in their throats.
C. gill arches that are not covered by an operculum, which prevents hiding places for gill parasites.
D. digestive tracts that are able to process most substrates, which has eliminated the need for feeding specialization.
E. ability to change color in relationship to their environment.

Back 29

B. a second set of jaws in their throats.

Front 30

40. Two populations that inhabit the same area but remain genetically distinct can best be called
A. species.
B. subspecies (races).
C. polymorphic.
D. allopatric species.
E. sympatric species.

Back 30

A. species.

Front 31

41. The biological species concept of Ernst Mayr cannot be applied to
A. sympatric organisms.
B. allopatric organisms.
C. eukaryotic organisms.
D. prokaryotic organisms.
E. asexually-reproducing organisms.

Back 31

E. asexually-reproducing organisms.

Front 32

43. Which statement is true about speciation on island archipelagos?
A. Speciation is slow because it depends on emigration from the mainland.
B. Most speciation occurs allopatrically.
C. Ecological competition may cause new species to go extinct slowing speciation.
D. Speciation by polyploidy is most common.
E. Species clusters are less common.

Back 32

B. Most speciation occurs allopatrically.

Front 33

44. Which form of speciation is most rapid?
A. allopatric speciation on the mainland
B. allopatric speciation on island archipelagos
C. sympatric speciation via polyploidy
D. sympatric speciation via disruptive selection
E. sympatric speciation via character displacement

Back 33

C. sympatric speciation via polyploidy

Front 34

45. Several species of sea urchins may inhabit the same tide pool and their reproductive periods overlap. Although they practice external fertilization, they seldom interbreed because eggs produce chemicals that are only attractive to sperm of their own species. This is an example of a _________ barrier involving _______________.
A. prezygotic; geographic isolation
B. prezygotic; temporal isolation
C. prezygotic; gametic isolation
D. postzygotic; gametic isolation
E. postzygotic; hybrid infertility

Back 34

C. prezygotic; gametic isolation

Front 35

46. Many male songbirds have very distinctive songs that are used to attract females. These songs are an example of a(n) ________ isolating mechanism.
A. postzygotic, ecological
B. prezygotic, behavioral
C. prezygotic, temporal
D. postzygotic, mechanical
E. prezygotic, gametic

Back 35

B. prezygotic, behavioral

Front 36

47. Due to character displacement, two closely related species may differ most morphologically when they
A. are allopatric.
B. are sympatric.
C. occupy the same niche.
D. occupy different niches.
E. share a common ancestor.

Back 36

B. are sympatric.

Front 37

48. Several new tetraploid species of plant known as the salsifies have arisen in western North America. These new species arose from diploid species that went through the process of allopolyploidy. This mode of speciation is known as ________ and it occurs _______.
A. allopatric speciation; almost instantaneously
B. allopatric speciation; very slowly
C. sympatric speciation; almost instantaneously
D. sympatric speciation; very slowly
E. adaptive radiation; very slowly

Back 37

C. sympatric speciation; almost instantaneously

Front 38

50. Imagine two species of birds with similar beak sizes and diets. Where the two species are allopatric, we would expect that their beak sizes
A. should differ more than when sympatric.
B. should differ less than when sympatric.
C. should be larger than when sympatric.
D. should be smaller than when sympatric.

Back 38

B. should differ less than when sympatric.

Front 39

51. If two species are able to mate and produce an offspring which can mate with itself, but is unable to mate with either parent's species, it is an example of
A. allopatric speciation.
B. sympatric speciation via disruptive selection.
C. sympatric speciation via polyploidy.
D. a species cluster.
E. character displacement.

Back 39

C. sympatric speciation via polyploidy.

Front 40

52. If a new species is produced by the interbreeding of two members of distinct species, this would be __________ speciation achieved via _________.
A. allopatric; autopolyploidy
B. allopatric; allopolyploidy
C. sympatric; autopolyploidy
D. sympatric; allopolyploidy
E. sympatric; divergence

Back 40

D. sympatric; allopolyploidy

Front 41

58. Choose the best cause and effect sequence for the process of speciation by natural selection.
A. Variation --> Selection --> Reproductive Isolation --> Mutation --> Speciation
B.

Mutation --> Variation --> Selection --> Reproductive Isolation --> Speciation

C.

Speciation --> Reproductive Isolation --> Selection --> Mutation --> Variation

D. Variation --> Reproductive Isolation --> Speciation --> Mutation --> Selection
E. Selection --> Speciation --> Reproductive Isolation --> Variation --> Mutation

Back 41

B.

Mutation --> Variation --> Selection --> Reproductive Isolation --> Speciation

Front 42

59. An example of temporal isolation would be
A. one plant species blooms in June-July and a second plant species blooms in August-September.
B.

one plant species is pollinated by bees and a second plant species is pollinated by moths.

C.

two plant species live on the same mountainside but one lives on rocky outcrops and the other in open meadows.

D. two plant species have incompatible gametes.

Back 42

A. one plant species blooms in June-July and a second plant species blooms in August-September.

Front 43

60. Reinforcement is most likely to drive the evolution of
A. prezygotic isolating mechanisms, because selection favors alleles that prevent hybridization.
B.

postzygotic isolating mechanisms, because selection acts after the formation of hybrids.

C.

prezygotic isolating mechanisms, because selection favors alleles that promote hybridization.

D. postzygotic isolating mechanisms, because hybrids have low fitness relative to the parents.

Back 43

A. prezygotic isolating mechanisms, because selection favors alleles that prevent hybridization.

Front 44

62. NASA Scientists send a small population of dogs to a new planet in order to test if it will be hospitable for human colonization. Through a random lottery, only Great Dane and St. Bernard dog breeds are sent, and the resulting population consists of tall, longhaired dogs. After 100 years these dogs return to earth and are no longer able to mate with earth dogs. This scenario is an example of
A. allopatric speciation through genetic drift.
B. allopatric speciation through natural selection.
C. sympatric speciation through genetic drift.
D. sympatric speciation through natural selection.

Back 44

A. allopatric speciation through genetic drift.

Front 45

63. Scientists investigating speciation in fruit flies divided a single population of flies into separate populations that each lived in their own cage on one of two food sources: maltose-based food or starch-based food. After several generations, the flies’ mate preference was tested, and it was found that flies strongly preferred to mate with other flies that were raised on the same food source. This results suggests that
A. selection on food source indirectly led to the evolution of reproductive isolating mechanisms.
B. selection on reproductive isolating mechanisms indirectly led to the evolution of different food preferences.
C. reproductive isolating mechanisms evolved primarily through genetic drift.
D. different food preferences evolved primarily through genetic drift.

Back 45

A. selection on food source indirectly led to the evolution of reproductive isolating mechanisms.

Front 46

66. Diversification of mammals after the extinction of the dinosaurs is considered an adaptive radiation because a few mammal species rapidly evolved into most of the current mammalian lineages in a relatively short amount of time. This diversification was partially driven by the evolution of endothermic homeostasis in mammals, which is in example of
A. allopatric speciation.
B. reproductive isolation.
C. a key innovation.
D. hybridization.

Back 46

C. a key innovation.