The Origin Of Species Test Questions & Answers Chapter.22

Biology, 12e (Raven)

Chapter 22 The Origin of Species

1) The ________ model assumes that evolution occurs in spurts, between which there are long periods of stasis with little evolutionary change.

2) The ________ definition of species says that a species is a group of organisms that are reproductively isolated from other such groups.

3) The phenomenon where one species diverges into many by occupying a different habitats within a region is called ________.

4) The process by which related species become more different in order to reduce competition is called ________.

5) 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.

6) 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

7) 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

8) 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

9) Which isolating mechanism is postzygotic?

A) hybrid sterility

B) behavioral isolation

C) ecological isolation

D) mechanical isolation

E) temporal isolation

10) Evolution acts at the level of the

A) ecosystem.

B) population.

C) species.

D) community.

11) 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.

12) 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.

13) 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

14) Scientists observed that marine bryozoan fossils lack intermediate forms. This evidence supports which hypotheses? Check all that apply.

A) Evolution occurs in spurts, alternating with long periods of little change.

B) Evolution proceeds steadily, with gradual, incremental change in a given evolutionary line.

C) There is variability in the rate of evolution.

D) Evolution proceeds at a constant rate that is the same for all organisms.

15) If populations within the same area split into species, the process is known as

A) sympatric speciation.

B) allopatric speciation.

C) racial speciation.

D) ecotypical speciation.

E) reproductive speciation.

16) 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.

17) Scientists found that different beak shapes correlate with different mating songs in Darwin's finches. Which hypothesis does this support?

A) Darwin's finches are not different species according to the Biological Species Concept.

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

C) Mating songs are primarily determined by the acoustics of different beaks.

D) Adaptation to different food sources likely occurred after reproductive isolation in Darwin's finches.

18) Once species have formed, they keep their identity by

A) developmental differences.

B) genetic blocks.

C) isolating mechanisms.

D) somatic mutations.

E) structural modifications.

19) Many species might coexist in a particular environment by occupying different ecological

A) biomes.

B) niches.

C) territories.

D) domains.

E) ranges.

20) Males of many marsupial species have forked penises that are incompatible with the anatomy of female placental mammals. What type of isolating mechanism does this represent?

A) ecological isolation

B) temporal isolation

C) mechanical incompatibility

D) hybrid sterility

E) prevention of gamete fusion

21) 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.

22) 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.

23) 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.

24) Select all of the following that are postzygotic isolating mechanisms.

A) Hybrids are sterile.

B) Hybrids develop abnormally.

C) Hybrids fail to become established in nature.

D) Hybrids cannot be formed.

25) 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 became reproductively isolated by living on a different island, then later colonized the other islands and acquired new adaptations.

D) many ancestral bird species colonized each island.

26) 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.

27) 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 in each ocean diverged prior to the formation of the Isthmus of Panama.

C) snapping shrimp species in each ocean diverged after the formation of the Isthmus of Panama.

D) creation of the Panama Canal allowed interbreeding between populations of shrimp.

28) 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 a set of chromosomes from both parental species. H. anomalus is most likely an example of instantaneous speciation through

A) allopolyploidy.

B) autopolyploidy.

C) parthenogenesis.

D) hybrid sterility.

29) Check all that apply: Members of the same biological species can

A) have several isolated gene pools.

B) differ from other species in one or more characteristics.

C) generate fertile offspring with the members of a different species.

D) interbreed freely with each other.

30) 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.

31) Select the concepts emphasized by Ernst Mayr's biological species concept. Check all that apply.

A) hybridization between different species

B) production of fertile offspring within the species

C) populations in zoos

D) reproductive isolation from other species

32) Two hundred years ago, the fly species Rhagoletis pomonella only laid its eggs on fruit of the hawthorn tree. Today, different "host races" of R. pomonella lay their eggs on hawthorns OR apples. Apples occur within the range of hawthorns, so divergence between apple flies and hawthorn flies could be the first step in sympatric speciation. Choose the evidence that would suggest that R. pomonella is currently undergoing sympatric speciation. Check all that apply.

A) Apple flies typically mate with apple flies, and hawthorn flies typically mate with hawthorn flies.

B) Apple flies and hawthorn flies emerge from their hosts at different times of the year.

C) Apple flies and hawthorn flies are able to form fertile hybrids.

D) Apple flies and hawthorn flies are physically indistinguishable from each other.

33) 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, thus producing two populations of squirrels. What must occur for the two populations of squirrels to be considered separate species?

A) The two squirrel populations must feed on different species of plants.

B) The environment must change so that the populations exist in distinct habitats.

C) The fur color or other morphological characteristic of the two squirrel populations must become distinct.

D) The two squirrel populations must select mates using different behaviors.

E) The two squirrel populations must be reproductively isolated. 

34) 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

35) 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.

36) The most common mechanism for sympatric speciation in plants is

A) polyploidy.

B) geographic isolation.

C) spontaneous mutation.

D) punctuated equilibrium.

E) disruptive selection.

37) 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.

38) 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.

39) 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.

40) Which examples would be considered different species under the biological species concept? Check all that apply.

A) Two bear species are able to breed in zoos, but have separate ranges in nature.

B) Two skunk species look morphologically similar, but are unable to interbreed.

C) Two snake species look different, but often form fertile hybrids.

D) Two plant species with no gene flow between them.

E) Two tree species have different leaf shapes, but form hybrids in their overlapping ranges.

41) 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.

42) 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

43) 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 that ________.

A) prezygotic; causes geographic isolation

B) prezygotic; causes temporal isolation

C) prezygotic; prevents gamete fusion

D) postzygotic; prevents zygote fusion

E) postzygotic; causes hybrid infertility

44) Many male songbirds have very distinctive songs that are used to attract females. These songs are an example of a ________ isolating mechanism.

A) postzygotic, ecological

B) prezygotic, behavioral

C) prezygotic, temporal

D) postzygotic, mechanical

E) prezygotic, gamete fusion

45) 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.

46) Several new tetraploid species of a plant called salsify (Tragopogon) known as salsify have arisen in western North America. These new species each arose from a diploid species that went through the process of allopolyploidy. This mode of speciation is a type of ________ 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

47) Why do the Galápagos Islands and the Hawaiian Islands have so many endemic species of flies and birds? Check all that apply.

A) There are numerous islands in each archipelago.

B) There is adequate distance between islands to allow divergence.

C) The founder effect was common when islands were colonized.

D) Each bird or fly species has many common ancestors.

48) 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 be more different than when sympatric.

B) should be more similar than when sympatric.

C) should be larger than when sympatric.

D) should be smaller than when sympatric.

49) 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.

50) 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

51) Choose the factors contributing to adaptive radiation of Drosophila in the Hawaiian Islands. Check all that apply.

A) New islands are constantly being formed.

B) There are high rates of mutation due to radioactive materials in the lava flows.

C) The islands are highly volcanic.

D) Drosophila species have no predators on the Hawaiian Islands.

52) Choose the true statements about the diversity of Darwin's finches on the Galápagos Islands. Check all that apply.

A) All of the finch species share a common ancestor that colonized the islands.

B) Prior to the adaptive radiation of finches, there were no unoccupied habitats in the Galápagos Islands.

C) Competition among finches for food sources led to character displacement of beak shapes.

D) Beak shape is not an important key innovation.

53) Which statements about the Lake Victoria cichlid fishes are true? Check all that apply.

A) The adaptive radiation of the estimated 300 species of cichlid fish was very rapid and took place during the last 200,000 years.

B) The adaptive radiation of the Lake Victoria cichlids may have resulted from a key evolutionary innovation.

C) Speciation of the Lake Victoria cichlids was mainly sympatric.

D) The diversity of the Lake Victoria cichlids continues today because the lake is devoid of predators.

E) Many of the Lake Victoria cichlids have very specialized adaptations that allow them to occupy diverse habitats within the lake.

54) Which statements about gradualism and punctuated equilibrium are true? Check all that apply.

A) Darwin's publication On the Origin of Species changed the view of evolution from gradualism to that of punctuated equilibrium.

B) According to the theory of punctuated equilibrium, evolutionary change occurs only during brief periods of speciation.

C) Stasis is likely caused by periods of disruptive and directional selection.

D) Gradualism suggests that evolutionary change is not linked to speciation.

55) 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

56) Which is an example of temporal isolation?

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.

57) 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.

58) Two species regularly come into contact and form hybrids that have higher fitness than either of the parental species. What are some likely consequences of regular hybridization between these species? Check all that apply.

A) evolution of a third species

B) reinforcement of prezygotic isolating mechanisms

C) extinction of one or both of the parental species.

D) increased gene flow between the parental species

E) complete reproductive isolation of the two original species

59) 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.

60) Indicate the scenario(s) that could directly result in sympatric speciation. Check all that apply.

A) Two sunflower species cross to form a healthy hybrid individual with equal copies of chromosomes from each parental species.

B) A new river channel divides a population of beetles into two populations.

C) A large fence blocks the intermingling of two populations of a species.

D) A subset of flies within a larger population colonizes a new host plant.

61) Select the reasons why adaptive radiations are often observed on remote volcanic islands. Check all that apply.

A) When a new volcanic island forms, there are many empty niches.

B) Only a few individuals reach remote islands.

C) Remote islands have more plant diversity than the mainland does.

D) Evolution is intrinsically faster on islands than on the mainland.

62) 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 an example of

A) allopatric speciation.

B) reproductive isolation.

C) a key innovation.

D) hybridization.

63) Courtship for Anolis lizards involves the male displaying a dewlap (skin under the throat area) that varies in appearance based upon the species. Lizards that are found in darker, more shaded environments will have dewlaps that are lighter in color because they are more noticeable by potential mates. Which of the following mechanisms best explains how speciation is at work in this example?

A) Postzygotic isolation

B) Reinforcement

C) Genetic drift

D) Natural selection

64) How many mass extinctions have been identified during the history of life on Earth?

A) five

B) six

C) four

D) one

E) none

65) Select the phrases that apply to the sixth mass extinction.

A) human influenced

B) asteroid

C) Cretaceous period

D) slow rebound of biodiversity

66) After an initial rapid rise in the number of species on Earth, there was a plateau that experienced very little fluctuation in the number of species.

67) Select the following statements that are related to mass extinctions.

A) A mass extinction occurs when extinctions sharply outpace the formation of new species.

B) Periods of mass extinctions have occurred five times over the history of life on Earth.

C) The most severe mass extinction occurred at the end of the Cretaceous period.

D) The current level of species diversity is so high it is highly unlikely that another mass extinction could occur. 

E) During periods of mass extinction, dominant groups of organisms are protected and survive to repopulate.