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A) B) C) D) E)
1. A bacteriologist is studying two asexually reproducing strains of E. coli. The two require different amounts of trace minerals for survival; on these grounds, the bacteriologist determines that they are separate species. In making his determination, he is using which species concept or concepts? biological species concept ecological species concept morphospecies concept phylogenetic species concept None of the answer options is correct.
2. The figure below shows a ring species complex for seven populations of salamander. The seven populations are arranged around a low valley that the salamanders cannot cross.
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A) B) C) D) E)
Data from: http://www-tc.pbs.org/wgbh/evolution/library/05/2/images/l_052_05_l.jpg reinforcement. pre-zygotic isolation. post-zygotic isolation. ecological isolation. temporal isolation.
3. The figure below shows an example of a ring species complex for seven populations of salamander. The seven populations are arranged around a low valley that the salamanders cannot cross.
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Data from: http://www-tc.pbs.org/wgbh/evolution/library/05/2/images/l_052_05_l.jpg
A) B)
C) D)
Which of the following statements BEST reflects the spread of alleles between E.e. crocreatur and E.e. klauberi? These two populations do not share any alleles because they are geographically separated from one another. These two populations share alleles, but alleles in E.e. crocreatur that are present in E.e. klauberi arrived in that population by travelling through the “ring� of other species. These two subspecies probably arose through allopatric speciation when the valley in the center divided an original population. The original population probably covered the entire distribution shown in the figure, but when the valley formed the different populations speciated.
4. A drawback of the biological species concept is that it CANNOT be applied to: populations of a single species living in different places. plants, which do not physically come in contact with each other when transferring gametes the way that animals do. C) highly polymorphic species. A) B)
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D) E)
extinct and asexual organisms. All of these choices are correct.
D) E)
5. Ring species such as the greenish warbler complicate the biological species concept because: at least some of their populations are reproductively isolated from one another but can still exchange genetic material. at least some of their populations overlap spatially, but individuals in those populations do not interbreed with one another. individuals in at least some populations interbreed with individuals from other species. ring species comprise populations that are in the process of allopatric speciation. None of the other answer options is correct.
A) B) C) D) E)
6. In some large groups of plants, including dandelions, oaks, and willows, the biological species concept is complicated because the process of _____ allows gene flow to occur between good _____ that can be easily distinguished based on appearance. hybridization; morphospecies hybridization; ecological species allopatric speciation; ring species polyploidy; evolutionary species polyploidy; ring species
A) B) C) D)
7. Two individuals of opposite sex are members of the same species if they: look similar. similarly. they share genetic information. can produce fertile offspring.
A) B) C)
8. Two populations are the same species if their members can potentially breed with each other. A) True B) False
A) B) C) D)
9. Unlike the biological species concept, the morphospecies concept relies on: physiology. phenotype. behavior. offspring.
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10. When determining if asexual organisms are part of the same or different species, it is useful to use the: (Select all that apply.) A) biological species concept. B) morphospecies concept. C) ecological species concept. D) phylogenetic species concept.
11. A paleontologist is studying a group of fossils from its first appearance in the fossil record to its extinction. She determines that the group descends from a single common ancestor and gave rise to no new species. Its appearance is distinct from any other group of fossils. Based on this information, she decides that it is a new species. In coming to this decision, which species concept or concepts is she using? (Select all that apply.) A) biological species concept B) morph species concept C) phylogenetic species concept D) ecological species concept
12. When you use a field guide to identify a species by its appearance, you are applying the _____ concept. A) morphospecies B) biological species C) ecological species D) evolutionary species
13. While in South America, you come across what you think are two groups of birds in the same location. They are nearly identical aside from their color. After years of observation, you conclude that the birds eat similar diets and share similar behaviors but do not reproduce with each other. These groups of birds appear to be an example of: A) a single biological species. B) a single ecological species. C) ring species. D) two different species on the basis of the ecological niche occupied. E) two different species on the basis of reproductive behavior.
14. The biological species concept states that species are actually or potentially _____ populations that are reproductively isolated from other such groups. A) interbreeding
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B) C) D) E)
A) B) C) D)
cohabitating naturally selected physically similar genetically identical
15. A rule of thumb known as the morphospecies concept holds that morphology: may vary within a species on the basis of sex. is generally consistent within a species. is not a reliable indicator of common species. may vary within a species on the basis of life stage.
16. It is difficult to apply the biological species concept to bacteria because: A) bacteria are haploid. B) bacterial reproduction is asexual. C) bacteria are not considered species because they lack morphological variation. D) bacteria are found everywhere, there are no individual populations or species.
17. In general, males and females of the same species can produce fertile offspring. A) True B) False
18. Which of the following is NOT a characteristic of species? the ability of all members to exchange genetic material with one another the ability to produce fertile progeny individuals in different phases of development have different numbers of chromosomes D) a common evolutionary ancestry among all individuals E) shared characteristics such as shape, size, and color (in individuals of the same life stage and sex) A) B) C)
19. Which of the following species concepts is described by populations that are not in direct physical or reproductive contact, but do exchange genetic material through linking populations of the same species? A) ring species B) ecological species C) evolutionary species
20. Which of the following species concepts might differentiate species on the basis of
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A) B) C)
specific dietary requirements? ring species ecological species evolutionary species
21. Which of the following species concepts might differentiate species on the basis of descent from a common ancestor? A) ring species B) ecological species C) phylogenetic species
A) B) C) D)
22. The Biological Species Concept is least useful for identifying: plant species. animal species. species represented by fossils. species in marine environments.
23. Imagine that a zoo in Sri Lanka has started an elephant-breeding program. Zookeepers have introduced an Indian and Sri Lankan elephant into the same enclosure. What will be the result of this mating? A) These elephants will fail to produce fertile offspring. B) These elephants will produce infertile offspring (i.e., like a mule). C) This mating will demonstrate that these elephants are reproductively isolated from each other. D) This mating will demonstrate that these elephants are not members of the same species. E) This mating will demonstrate that these elephants are members of the same species, and will produce fertile offspring.
24. All members of a species can in principle mate with members of the same species but of the different sex. Two populations would not be considered part of the same species if they do not actively breed (even if they potentially could). A) True B) False
A) B) C)
25. Which of the following statements is TRUE regarding the biological species concept? The biological species concept was first described by Charles Darwin. The biological species concept is synonymous with the morphospecies concept. Given the generation time of certain organisms, the biological species concept can Page 7
D) E)
be difficult to test. The biological species concept can be applied easily to all bacterial species. Using the biological species concept, scientists can determine which organisms in the fossil record likely belonged to the same species.
26. If two populations are reproductively isolated from one another (like certain populations of Russian warblers), they must be genetically isolated from each other and therefore cannot belong to the same species. A) True B) False
27. A researcher is trying to determine whether different populations of asexually reproducing bacteria belong to the same species. What concept will be MOST helpful in making this determination? A) the biological species concept B) the ecological species concept C) the evolutionary species concept
28. Which of the following statements is TRUE regarding hybridization? A) Hybridization occurs in plants more often than in animals. B) Hybridization involves the transfer of genetic material between members of similar species. C) Natural selection sometimes acts against progeny that result from hybridization. D) Hybridization can result in fertile offspring. E) All of these choices are correct.
29. Flower A blooms in June while flower B, a close relative of A, blooms in August. A researcher is raising a population of flower B in a controlled growth chamber. Over time the researcher manipulated the day length in the growth chamber and eventually manages to induce some individuals of flower B to bloom in June. The researcher finds that she can cross these individuals with flower A individuals and they produce viable, fertile offspring. What can she conclude about flower A and flower B? A) A and B aren't a good example of separate species. B) A and B are genetically incompatible. C) A and B are temporally reproductively isolated from each other. D) The fact that B's blooming time can be manipulated suggests it should not be regarded as a species distinct from A. E) A and B are not pre-zygotically isolated from one another.
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30. The graph in Figure 22.9, below, shows that the extent of the adaptive radiation of the Galรกpagos finches is correlated with the number of islands present in the archipelago. What can be concluded from the graph?
A) B) C) D) E)
This shows that rates of speciation are correlated with the net total land area available. This shows that each island hosts sympatrically speciating populations. This shows that opportunities for geographic isolation are a key component of the speciation process. This shows that allopatric speciation tends not to occur on islands. This shows that the balance between rates of sympatric and allopatric speciation is governed by mutation rates.
31. When we look at islands across the planet (think the islands of the Galรกpagos and Hawaii) we see that there are a remarkable number of island endemic species, species that are found nowhere else. What is a possible explanation for this observation? A) Extinction rates are lower in islands so species that have gone extinct elsewhere persist on islands. B) Sympatric speciation on islands is easier than in mainland environments because rates of chromosomal evolution are higher on islands. C) Sympatric speciation on islands is easier than in mainland environments because
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D) E)
levels of disruptive selection are higher on islands. Island isolation promotes allopatric speciation. Vicariance events are more common on islands than in mainland environments.
32. A researcher finds two closely related species of rodent, A and B, living sympatrically on a coastal peninsula. Geological analysis suggests that higher sea levels in the past have occasionally cut off parts of the peninsula—with the lower parts of the peninsula being under water and higher parts becoming separate islands. Do you think species A and B arose sympatrically or allopatrically? Explain your answer.
33. The example of speciation via vicariance given in Figure 22.7 focuses on the impact of the formation of the isthmus of Panama on the populations of snapping shrimp living in the shallow waters of the West Caribbean and East Pacific. Would you expect to see a similar pattern of Pacific/Caribbean sister species in other shallow-water organisms?
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Photo source: Dr. Arthur Anker, National University of Singapore, Singapore.
34. A single species of fish, the three-spined spinyback, once inhabited a large lake. At some point in the lake's history, lava flowed from a nearby volcano into the lake cutting it into three completely isolated mini-lakes. Despite the heat from the lava, a few individuals from the original population of spinyback survive in each mini-lake. Three million years later, a researcher finds that each mini-lake is inhabited by its own species of spinyback. Which of the following figures MOST closely reflects how the three species of spiny back are related to one another?
A) B) C) D)
tree M tree H tree K tree L
35. What conditions must be met if we are to establish that a species arose via sympatric speciation? Give an example in which these conditions are met.
36. An ancestral population is split into two different groups, and they no longer interbreed after separation. Which of the following CORRECTLY describes the number of genetic differences that would be seen between the two populations?
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A) B) C)
graph M graph H graph K
37. Several species of fireflies are active on the same summer nights in the same fields. Males and females recognize one another by their distinctive flashing patterns. This is an example of what kind of reproductive isolation? A) pre-zygotic, behavioral isolation B) pre-zygotic, temporal separation C) pre-zygotic, ecological separation D) post-zygotic, lock and key E) post-zygotic, ecological separation
38. Horses and donkeys can interbreed, but their offspring (mules) are infertile. This is an example of what kind of reproductive isolating mechanism? A) pre-zygotic, behavioral isolation B) pre-zygotic, temporal separation C) post-zygotic, behavioral isolation D) post-zygotic, genetic incompatibility E) post-zygotic, ecological separation
39. A large population of mice (2000 individuals) lives in an area dominated by small shrubs in the desert. When the population size got too high, a small group of 6 individuals left and colonized an area adjacent to the original population's home, but this area is primarily dominated by trees instead of shrubs. There is no gene flow between the dispersers and the original population. A researcher sequenced the genomes of representative individuals from both populations and found substantial genetic differences between them. Which of the following would MOST account for the amount of genetic differences observed?
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A) B) C) D)
Divergence between the two populations was caused solely by drift. Divergence between the two groups is high because of gene flow. Since the original dispersal event, the small population will have diverged more than the large population. The divergence between populations could only have been caused by stabilizing selection.
40. Male birds of different species sing species-specific songs to attract mates. Females only mate with males that sing their species-specific song. This is an example of: A) pre-zygotic isolation. B) post-zygotic isolation. C) reinforcement. D) temporal isolation.
41. New species can form through allopatric or sympatric speciation. Which of the following mechanisms will act more strongly on populations that are initially separated in allopatry than on those initially separated in sympatry? A) disruptive selection B) gene flow C) genetic drift D) reinforcement
42. Consider the two phylogenies below of five species of related flowers that hold nectar as a reward for their pollinators, five related species of moths, in their spur.
The similar pattern of the phylogenies suggests the characteristics coevolved with one Page 13
A) B) C) D)
another. Which of the following is an accurate statement reflecting the figure above? The flowers and moths experienced the same allopatric speciation events during their history. The flowers and moths coevolved, so that spur-length and tongue-length each evolved because of changes in the other. The flowers and moths cannot co-speciate because co-speciation only occurs in host-parasite relationships. This is not an example of co-speciation. Each phylogeny represents the variation present in each population of the flower and the moth.
43. Biochemical recognition systems within the stigma of a flowering plant prevent the pollen from a different species from developing a pollen tube and fertilizing its eggs. This is an example of what kind of reproductive isolation? A) pre-zygotic, behavioral isolation B) pre-zygotic, temporal separation C) pre-zygotic, lock and key D) post-zygotic, temporal separation E) post-zygotic, ecological separation
44. Which of the following statements reflects one way that two different species can produce hybrid offspring? A) They are post-zygotically isolated, but occasionally will mate anyway. B) The two species are probably hybrids as well, so reproduction can occur between the two. C) The amount of divergence between the two species allows for production of offspring, but they are sterile. D) They are distantly related but occupy similar habitats.
45. Examine Figure 22.10, below. Which of the following statements is the MOST accurate in reflecting levels of genetic divergence between different species of lice?
Photo sources: (left) Photo by Alex Popinga, courtesy of James Demastes; (right)
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Richard Ditch @ richditch.com. A)
G. cherriei and G. costaricensis will have accumulated the most genetic differences between them relative to the other Geomydoecus species because they share the most recent common ancestor.
B)
G. cherriei and G. costaricensis will have accumulated the fewest genetic differences between them relative to the other Geomydoecus species because they share the most recent common ancestor. G. cherriei and G. costaricensis will have the same number of genetic differences as O. cherrieri and O. heterodus because they coevolved together. G. cherriei and G. costaricensis will have the same number of genetic differences from G. chapini because speciation could not occur in the lice without genetic differences.
C) D)
46. The longer two species have been separated, the greater the number of genetic differences between them. A) True B) False
47. Two species of frog mate in the same pond. One breeds in early summer and one in late summer. This is an example of what kind of reproductive isolation? A) pre-zygotic, behavioral isolation B) pre-zygotic, temporal separation C) pre-zygotic, ecological separation D) post-zygotic, temporal separation E) post-zygotic, ecological separation
48. Imagine a very deep lake with multiple species of fish. The lake has many different regions (i.e., shallow water with high light penetrance, deep water with low light penetrance). A phylogeny of the fish shows that they have all descended from a common ancestor. Which of the following is the MOST likely cause of speciation in fishes in this lake? A) allopatric speciation B) peripatric speciation C) sympatric speciation
49. Reproductive isolating mechanisms are divided into categories based on when they act. _____ isolating factors prevent fertilization from taking place; _____ isolating factors result in failure of the fertilized egg to develop into a fertile individual.
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A) B) C) D)
Pre-zygotic; pre-zygotic Pre-zygotic; post-zygotic Post-zygotic; post-zygotic Post-zygotic; pre-zygotic
50. Imagine that a researcher discovers two new similar species of bats in the same geographic area. Amazingly, one of these species preys upon insects during the day. The other speciesas one would expectis nocturnal and only feeds during the night. These two bat species would be considered to be _____ separated. A) temporally B) allopatrically C) energetically D) peripatrically
51. Recall the example of different ladybug species described in the text, which each feed on a different species of plant. If two such species inhabit the same types of plants but in different locations (i.e., one near the base of the plant and the other on the uppermost leaves), these species would be considered to be _____ separated. A) temporally B) ecologically C) energetically D) both temporally and ecologically
52. Post-zygotic reproductive isolation may be due to temporal or ecological separation. A) True B) False
53. You observe two groups of frogs that are closely related. Males from each group “sing” with a species-specific song to attract a female frog. Females only respond to songs sung by males of their species. This is an example of _____ separation and _____zygotic reproductive isolation between two species. A) ecological; pre B) ecological; post C) behavioral; pre D) behavioral; post
54. You observe two groups of birds that appear to be closely related. Males from the first group have bright red stripes on their tail feathers that they display in a courtship dance
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A) B)
preceding mating. Females only respond to coloring patterns exhibited by males of their species. This is an example of _____-zygotic reproductive isolation between two species. pre post
55. You would expect similar species with a different number of chromosomes to be genetically compatible and therefore able to reproduce. A) True B) False
56. Imagine that a scientist wants to create a new species of minionsone that is a cross between a shark and a wolf. To his dismay, when he introduces shark sperm and wolf eggs into a petri dish, no viable embryos form. Why? A) The wolf eggs and shark sperm are temporally separated. B) This is an example of behavioral isolationthe shark sperm do not perform the correct courtship rituals to fertilize the wolf eggs. C) This is due to selection among embryos favoring the pure shark and pure wolf lines. D) This must be due to post-zygotic isolation. E) This could be an example of pre-zygotic isolation, where the proteins of the shark sperm and wolf eggs do not interact properly; however, this could also be an example of genetic incompatibility, where genomic differences between sharks and wolves prevent the formation of viable embryos.
57. A zookeeper is very upset because one of the lions jumped the fence of his enclosure and mated with a neighboring tigress. This mating produced a “liger.” Which of the following statements is likely TRUE of this liger cub? A) Because of the similarities between the genomes of the lion and tiger, the liger cub will likely be very fertile and bear several offspring. B) The liger cub was born because of sequence similarities between the genomes of its parents. C) Due to genetic incompatibility between the lion and tiger, the liger cub will likely be sterile. D) The cub is the result of an incompatible lock-and-key mechanism between its parents. E) The liger cub was born because of sequence similarities in the genomes of the lion and tiger; however, due to genetic incompatibility the liger cub will likely be sterile.
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58. The reason that lions (which live in Africa) and tigers (which live in Asia) don't produce ligers (infertile offspring of lions and tigers) in the wild is likely the result of: A) an incompatible lock-and-key mechanism between the species. B) behavioral isolation of tigers and lions. C) temporal separation of lions and tigers. D) ecological separation of lions and tigers. E) both temporal and ecological separation of lions and tigers.
59. If two individuals from different species attempt to mate but fertilization fails to occur, this is likely the result of _____ factors. However, if such a mating produces a zygote that fails to form a viable embryo, this is likely the result of _____ factors. A) pre-zygotic; post-zygotic B) post-zygotic; pre-zygotic C) behavioral; pre-zygotic D) pre-zygotic; behavioral E) post-zygotic; lock-and-key
60. A little girl notices that she has a male dog and a female cat in her house at the same time. The dog and cat are the same size, and they seem friendly enough. Why don't these two animals ever mate? A) Because the dog and cat are temporally isolated from each other. B) Because the dog and cat are ecologically separated from each other. C) Because the dog and cat are behaviorally isolated from each other. D) Because the dog and cat are allopatric species. E) Because the dog and cat are peripatric species.
61. Which of the following represents genetic incompatibility? Two groups of ladybugs do not produce offspring because they feed on different species of plants and do not encounter each other. B) Two groups of beetles do not produce offspring because they feed on the same plants in different parts of the world. C) Two groups of birds do not reproduce because of incompatible courtship behaviors. D) Two groups of snakes do not produce fertile offspring because they have a different number of chromosomes. A)
62. You observe two groups of freshwater fish that spawn at the same time of the year and in the same pond. After females lay their eggs on the pond bottom, males of both species attempt to fertilize them. After some investigation you realize that sperm from both
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A) B)
species fertilize the eggs, but embryonic development stops shortly after fertilization when the eggs are fertilized by one species of males, but not by the other. This is an example of _____-zygotic reproductive isolation between the two species. pre post
63. You are an experienced naturalist and biologist and you observe two birds mating that you do not believe to belong to the same species. The eggs from this breeding do not hatch, and when you obtain one of the eggs, you find embryonic development stopped not long after fertilization. Which of the following conclusions is supported by these observations? A) Pre-zygotic isolation prevented successful reproduction. B) Post-zygotic factors prevented successful reproduction. C) Behavioral isolation prevented successful reproduction. D) Temporal isolation prevented successful reproduction. E) This is evidence to suggest the two types of birds are a single species.
64. In the southwestern desert of the United States there are temporary ponds that form only after heavy summer rains. As a naturalist, you visit these ponds and notice that female frogs mate with males of their own species based only on their calls. The lack of mating between species would be an example of _____ and _____. A) pre-zygotic isolation; temporal separation B) post-zygotic isolation; temporal separation C) pre-zygotic isolation; behavioral isolation D) post-zygotic isolation; behavioral isolation
65. Members of two species that are each other's closest relatives are found living sympatrically on a single island. What, if anything, can we conclude about their origins? A) One species originated sympatrically from the other. B) Both species originated sympatrically from a third species, which has gone extinct. C) Neither species originated sympatrically. D) One species originated allopatrically on the island and then gave rise to the other one via sympatric speciation. E) None of the answer options is correct.
A) B) C) D)
66. Why is it likely that MOST speciation is allopatric? Because gene flow between diverging populations is strong in allopatry. Because gene flow between populations prevents genetic divergence in sympatry. Because related species are always found in allopatry rather than in sympatry. Because vicariance events are common. Page 19
E)
Because disruptive selection between forms of traits in sympatric populations is always very strong.
67. Disruptive selection is a key component of sympatric speciation because it acts against the homogenizing effect of gene flow between the diverging populations. Imagine a case in which a bird population is undergoing disruptive selection on bill size in response to the availability of seeds to eat. The birds' environment contains two seed types, large and small, and lacks medium-sized seeds. Assume that a bird's ability to eat a seed is a direct function of its bill size (large bills are good for large seeds, and so on). Disruptive selection acts against birds with: A) large bills. B) small bills. C) large bills and birds with small bills. D) intermediate (medium-sized) bills. E) medium bills and birds with large bills.
68. Different species of fruit flies occupy each of the islands in the Hawaiian island chain, a group of volcanic islands that formed one after the other. One hypothesis for how the different fruit fly species formed is that, after each new island was formed, fruit flies from existing islands colonized it and subsequently diverged. If this hypothesis is correct, it would be an example of: A) allopatric speciation by dispersal. B) allopatric speciation by vicariance. C) peripatric speciation by vicariance. D) sympatric speciation by dispersal. E) sympatric speciation by vicariance.
69. In many regions of the world, there are closely related species of plants that are each pollinated by a single species of closely related insect species. Imagine that the flowers of each plant differ in the length of their corollas (a portion at the base of the flower that holds nectar, a reward for the pollinator), and that the insects differ in the length of their mouthparts that reach the nectar. Which of the following would you expect for the phylogenies of the flowers and their pollinators? A) The phylogenies would be random with respect to each other because we do not know if both groups speciated allopatrically or sympatrically. B) The phylogenies should have similar patterns, because the flowers and insects likely coevolved. C) The phylogenies should have similar patterns, but the insects probably evolved later so this is not an example of coevolution. D) The phylogenies should have similar patterns because the flowers and the insects Page 20
are reproductively isolated from one another.
70. Which of the following is the BEST explanation of why Plasmodium and ape phylogenies do not show a pattern of co-speciation? A) The ape phylogeny is incorrect and gorillas should be the closest relative to humans. B) Unlike the parasites in other host-parasite relationships, Plasmdium species are not an obligate parasite of humans. C) Ancestral humans may have had interactions with members of all other ape lineages and infection was random. D) Rates of speciation are slower in Plasmodium than humans, so the phylogenies would not resemble each other even if they had coevolved with one another.
71. Imagine a series of small forest patches (A–D) separated by grassland. A species of beetle can only live in areas with the forest, and they are unable to fly long distances. An original large population of these beetles lives in forest patch A (the largest of the forest patches), and can fly as far as the next forest patch over, patch B. Over time, each patch is successively colonized by a small group of individuals from the nearest population.
A) B) C)
After many years, each of the habitat patches is occupied by a different species of beetle, each one related to the original species in forest patch A. Speciation of the beetles was the result of _____ speciation. sympatric allopatric peripatric
72. Xenopus tropicalis and Xenopus laevis are two closely related species of frog. X. laevis has two times the number of chromosomes as X. tropicalis. Biologists assume that the species X. laevis arose through: A) sympatric speciation. B) polyploidy. C) reinforcement. D) coevolution.
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73. When taxonomists recognize subspecies, they are identifying: A) populations that are reproductively isolated from one another. B) populations with restricted enough gene flow to develop some population-specific traits, but that can still interbreed with members of other such populations. C) populations that will inevitably become separate species as reproductive isolation is nearly complete. D) populations with extremely restricted gene flow due to allopatric isolation. E) None of the other answer options is correct.
74. In general, sympatric speciation requires the action of _____ selection acting against hybrids. A) disruptive B) stabilizing C) directional D) artificial E) ecological
75. According to recent studies, the human malaria parasite Plasmodium falciparum was introduced to humans from: A) rhesus macaques. B) gorillas. C) chimpanzees. D) orangutans. E) pocket gophers.
76. When visiting Hawaii on vacation, a tourist notices that there are many different species of birds that look similar to one another, but are distinct in their ecology and in the morphology (beak size and shape) that helps make them successful in different habitats on the island. The tourist supposes they are closely related and result from an adaptive radiation. Which of the following statements would provide the STRONGEST evidence they are the result of an adaptive radiation? A) Some, but not all of the species can hybridize. B) Variation in beak length within any of the species is distributed like a bell curve. C) The phylogeny of the birds shows a single common ancestor for the group. D) The species move throughout all areas of the island.
77. Kingfishers in New Guinea are separated into distinct subspecies. Which two subspecies
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A) B) C) D)
would you expect to be MOST genetically different from one another? the subspecies that are furthest away from one another in distance the subspecies that diverged from one another first the subspecies that are most closely related to the mainland species of kingfisher the subspecies that live in the most ecologically different habitats
78. Two species of antelope ground squirrels are separated by the Grand Canyon. They are hypothesized to descend from a common ancestor, populations of which were separated as the canyon formed. If this hypothesis is correct, it would be an example of: A) allopatric speciation by dispersal. B) allopatric speciation by vicariance. C) peripatric speciation by vicariance. D) sympatric speciation by dispersal. E) sympatric speciation by vicariance.
79. Sympatric speciation: can occur instantaneously through formation of polyploid offspring. occurs whenever a physical barrier between two species is removed (i.e., a river dries up) and the two species start to interbreed. C) whenever hybrids mate with parental species. D) only occurs in bacteria. A) B)
80. If the human malaria parasite Plasmodium falciparum were the product of co-speciation, its closest relative could be found in: A) gorillas. B) chimpanzees. C) orangutans. D) pocket gophers.
81. Identical population-splitting events occurred simultaneously on two neighboring islands, Islands B and C, which are each initially home to different populations of rodent. The population-splitting event produced two subpopulations of rodent on each island: B1 and B2, and C1 and C2. We find that populations B1 and B2 cannot successfully interbreed with each other after 50,000 years, and that C1 and C2 can still interbreed after 100,000 years. Why does reproductive isolation arrive at different rates on these two islands?
82. For many species, hybridization results in sterile offspring, a process known as
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A) B) C) D)
reinforcement of isolation. An alternate way of viewing the process of reinforcement is: selection for hybrid individuals. selection against individuals that hybridize. behavioral isolation. ecological isolation.
83. Speciation always involves geographical separation of some kind between the two organisms. A) True B) False
A) B)
84. The extinction of a particular species may cause adaptive evolution in another. True False
85. The accumulation of different mutations in genetically separated populations is known as _____ and is the key to speciation. A) reproductive fitness B) genetic divergence C) intersexual selection D) reinforcement
86. Speciation requires that two populations become _____ isolated from each other. A) reproductively B) geographically C) temporally D) behaviorally E) zygotically
A) B) C) D)
87. Populations that are geographically separated from one another are called: allopatric. sympatric. hybrids. co-speciation.
88. _____ is a special case of explosive speciation in which new species form rapidly in response to numerous “open� ecological niches. A) Allopatric speciation
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B) C) D) E)
Peripatric speciation Adaptive radiation Co-speciation Sympatric speciation
89. _____ is the process by which two groups of organisms speciate in response to each other and at the same time. A) Allopatric speciation B) Peripatric speciation C) Adaptive radiation D) Co-speciation E) Sympatric speciation
90. _____ is the process by which two populations of the same species living in the same habitat diverge into separate species. A) Allopatric speciation B) Peripatric speciation C) Adaptive radiation D) Co-speciation E) Sympatric speciation
91. _____ is the gradual emergence of two or more species as a result of the geographic separation of two or more groups of animals of the same species. A) Allopatric B) Adaptive speciation C) Co-speciation D) Sympatric speciation E) Instantaneous speciation
92. In co-speciation, two groups of organisms speciate in response to each other and in a coordinated manner. A) True B) False
93. In _____ speciation, there is gene flow between populations that are in the process of diverging into two or more species. In _____ speciation, there is no gene flow between populations that are in the process of diverging into two or more species. A) allopatric; sympatric B) sympatric; allopatric
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C) D)
Both allopatric and sympatric are applicable to either description. Neither allopatric nor sympatric is applicable to either description.
94. If an organism has four copies of each chromosome, then it is: A) aneuploidy. B) diploid. C) haploid. D) tetraploid. E) polyploidy.
A) B) C) D) E)
95. _____ is a term that refers to multiple sets of chromosomes (e.g., four, six, or eight). Aneuploid Diploid Haploid Tetraploid Polyploid
96. If an organism has two copies of each chromosome, it is: A) aneuploid. B) diploid. C) haploid. D) tetraploid. E) polyploid.
97. Adaptive radiation is an acceleration of speciation and adaptation when there are a large number of ecological opportunities available. A) True B) False
98. Which of the following is TRUE regarding adaptive radiation? A) Adaptive radiation is more likely to occur within a mainland population than in a smaller population that underwent dispersal. B) Adaptive radiation is more likely to occur when there are a variety of similar and competing species. C) Adaptive radiation is more likely to occur in a population produced by a dispersal event than in a long-established population on a continent. D) Adaptive radiation tends to occur at a slower pace than genetic drift between two similar populations on the mainland.
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99. If an organism has a single copy of each chromosome, then it is: A) aneuploid. B) diploid. C) haploid. D) tetraploid. E) polyploid.
100. Which of the following is TRUE regarding sympatric speciation? A) Sympatric speciation requires physical separation of two populations. B) Sympatric speciation requires a selective disadvantage of hybrids (e.g., mediumbilled birds) of two diverging populations. C) Sympatric speciation requires a population in which all individuals have an equal chance of mating with one another. D) Sympatric speciation requires that all individuals use the same resources in the area where they are found.
101. Mammals are _____ organisms, whereas plants may be _____. A) haploid; diploid B) haploid; polyploid C) diploid; polyploid D) diploid; haploid
102. Which of the following statements is TRUE regarding polyploidy in plants? A) Autopolyploids are thought to be derived from plants of the same species. B) Allopolyploids are thought to be derived from plants of the same species. C) Polyploidy is more likely to be seen in mammals than plants. D) Hybridization events between plants cannot result in an alteration of chromosomal number.
103. The wide variety of finches Darwin observed in the Galรกpagos was thought provoking because they appeared to have descended from _____ population. Today, we regard this as an example of _____. A) the same; adaptive radiation B) more than one; convergent evolution C) the same; convergent evolution D) more than one; adaptive radiation
104. Imagine a scenario in which a common population of animals is separated into two
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A) B) C) D)
groups by a natural event. Over time, you might expect the two populations to become _____ genetically similar. This process is known as _____ speciation. less; sympatric more; sympatric less; allopatric more; allopatric
105. Imagine that European explorers sailing across the Pacific left several male and female pairs of pigs on a remote island with the intention of visiting again in future years to harvest fresh meat. This would MOST closely resemble a case of artificially induced allopatric speciation through: A) vicariance. B) dispersal.
106. When two populations have undergone divergence in allopatry long enough to have a difference of one fixed allele between the two populations, they are always then sufficiently different to be considered two different species. A) True B) False
107. When two populations have undergone divergence in allopatry long enough to be unable to produce fertile offspring, then they are different enough to be considered two different species. A) True B) False
108. You are a biologist on a trip to an island in the South Pacific. While on the island, you are allowed to collect DNA samples from a local species of rat that resembles a species seen on a nearby continent. If your DNA analysis also indicates the two species are closely related, you might conclude that the evolution of the two separate species was an example of _____ speciation through _____. A) allopatric; dispersal B) allopatric; vicariance C) sympatric; dispersal D) sympatric; vicariance
109. In general, allopatric species will evolve pre-zygotic isolating mechanisms more rapidly than sympatric species.
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A) B)
True False
110. You are a parasitologist interested in roundworms affecting frogs. You note that when two populations of frogs were separated long enough ago for them to speciate, their roundworms have also speciated. What is this process called? A) allopatric speciation B) co-speciation C) dispersal D) natural selection
111. A population of rare frogs is reduced by 90% in number when a large dam is constructed that obliterates most of their prior habitat. Which of the following is probably TRUE? A) The genetic diversity of the remaining frogs is unlikely to be different from the original population. B) The effects of natural selection on the smaller population's genetic variation will not be significant. C) Speciation cannot occur through genetic drift alone. D) The remaining frogs have reduced genetic diversity.
112. Some cases of hybridization that lead to instantaneous speciation result in alteration of chromosomal number. A) True B) False
113. You begin an experiment with two populations of E. coli that are each composed of 100 cells. The cells are all genetically identical (i.e., they are clones). You grow these populations in flasks on a lab bench under identical conditions with unlimited resources. What process will introduce genetic variation into these populations? Will identical genetic changes occur in each flask?
114. You begin an experiment with two populations of E. coli that are each composed of 100 cells. The cells are all genetically identical (i.e., they are clones). You grow them up in flasks on a lab bench under identical conditions with unlimited resources. After 10,000 generations, you analyze the genome of each population. Do you expect the genomes of each population to be identical after 10,000 generations? A) Yes, because the starting populations were genetically identical. B) Yes, because resources were unlimited.
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C) D) E)
Yes, because the same mutations will accumulate independently in each population. No, because natural selection was not a factor at any point in this experiment. No, because mutation and natural selection (once genetic variation is present) were factors in this experiment.
115. Imagine you are looking down on the top of a mountain. As you hike from the highest elevation to the lowest elevation, you find three different species of related mice. None of them is found at the same elevation, and the vegetation changes at each elevation level.
A) B) C) D)
At the highest elevation some of the individuals of species A mate with individuals in species B that make their way up from the middle elevation. Their offspring are unable to survive or reproduce in either elevation, and never reproduce. This is an example of: hybrid inviablity and infertility. pre-zygotic isolation. post-zygotic isolation. instantaneous speciation.
116. All else being equal, selection should more strongly favor reinforcement of reproductive Page 30
A) B) C) D) E)
isolation among related species in: allopatric populations over sympatric populations. sympatric populations over allopatric populations. peripatric populations over sympatric populations. peripatric populations over allopatric populations. allopatric populations over peripatric populations.
117. You are studying a species of frog in which individuals from two successive generations can no longer interbreed, suggesting that the offspring are a different species from the parents. If speciation occurred because of changes in chromosome counts between the parents and the offspring, would this be an example of speciation by natural selection? A) Yes, because all speciation events involve natural selection. B) Yes, because there is genetic variation present due to differences in chromosome numbers. C) Yes, because natural selection is involved whenever there is a difference in the genome size between the parents (species 1) and the offspring (species 2). D) No. Speciation occurred, but natural selection was not involved. E) No. Natural selection can only act on populations, not on individuals.
118. _____ is the process by which divergent populations undergo natural selection in favor of enhanced pre-zygotic isolation. A) Reinforcement B) Sexual selection C) Dispersal D) Peripatric speciation
119. Reinforcement refers to the development of _____-zygotic factors and is typically more rapid in species living in _____. A) pre; allopatry B) pre; sympatry C) post; allopatry D) post; sympatry
120. A neutral mutation is a mutation that _____ increase the reproductive fitness of an organism. A) does B) does not
121. Natural selection is always the driving force of speciation. Page 31
A) B)
True False
122. Which of the following describes reinforcement of reproductive isolation? A) the physical separation of two populations with diverging characteristics B) the reduced fitness of hybrid offspring C) the ability to identify and preferentially mate with only members of the same population D) an outbreak of disease that wipes out one of the two populations that would otherwise mate and form hybrid offspring
123. _____ is the primary force responsible for changes in allelic frequency of deleterious mutations. _____ is the primary force responsible for changes in allelic frequency of neutral mutations. A) Genetic drift; Natural selection B) Natural selection; Genetic drift
124. Over a long period of time, you would expect a deleterious mutation to _____ frequency within a large population. A) increase in B) decrease in C) increase or decrease in D) remain at the same
125. Over a long period of time, you would expect a neutral mutation to _____ frequency within a large population. A) increase in B) decrease in C) increase or decrease in D) remain at the same
126. The process by which sympatric speciation might occur would MOST likely be the result of: A) convergent evolution. B) adaptive radiation. C) natural selection. D) vicariance.
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127. Speciation due to genetic drift is typically a very _____ process. A) rapid B) slow C) convergent D) dispersive
128. If natural selection is the driving force for speciation of two competing subspecies, you would expect to see a bell-shaped distribution of selected phenotypes after selection. A) True B) False
129. If speciation were a result primarily of genetic drift, then you would expect to see a bellshaped distribution of most phenotypic characteristics. A) True B) False
130. Imagine that you had two populations of red-tailed hawksone with long tail feathers, the other with short tail feathers. Mating discrimination in this species could entail either hawks with long tail feathers preferentially mating with other hawks that have long tail feathers, or hawks with short tail feathers preferentially mating with other hawks that have short tail feathers. A) True B) False
131. Which of the following statements is TRUE regarding reinforcement? A) It “reinforces” reproductive isolation. B) It is associated with the selection of certain pre-zygotic factors. C) It limits the resources and energy wasted by a population on the production of “inefficient” hybrids. D) It is associated with “mating discrimination,” where individuals with a certain phenotype preferentially mate with individuals possessing the same phenotype. E) All of these choices are correct.
132. Imagine that a researcher is studying two different beaver populations. One of these populations consists of beavers with larger, rather unwieldy teeth that make eating difficult but that allow the beaver to take down very large trees. The other population consists of individuals with smaller teeth that make eating easier, but which are still capable of chewing through the wood of small trees. When a beaver dam fails, the two
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A) B) C) D) E)
populations merge. Hybrids with medium-sized teeth are poorly adapted to the environment: Their teeth are too big to make eating easy, but they are not big enough to permit the felling of large trees. If a mutation arises that causes beavers with smallersized teeth to preferentially mate with individuals having the same size teeth, this would result in reinforcement of _____ isolation. reproductive species-size analogous character temporal species ecological species
133. Speciation can occur in the absence of natural selection; for example, in speciation that results from instances of genetic drift. A) True B) False
134. Which of the following statements is TRUE regarding speciation? A) Natural selection is required for speciation to occur; even in instances of genetic drift, natural selection must play a role in the development of new species. B) Natural selection only plays a role in allopatric speciation; any speciation that results from sympatric speciation is the result of genetic drift. C) Natural selection and reinforcement are intimately connected and result in speciation due to the selection of specific post-zygotic factors. D) None of the answer options is correct.
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Answer Key 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32.
B B B D A A D A B B, C, D B, C A E A B B A C A B C C E B C B B E C C D Allopatrically. Populations isolated on the “islands� underwent genetic divergence in allopatry. Their current sympatry is thus simply a case of secondary contact, whereby previously diverged taxa come back into contact with each other. 33. Yes, the vicariance event (the closing of the waterways through the isthmus) would have the same impact on all populations of all taxa in the region, cutting Caribbean populations off from Pacific ones, and producing isolated daughter populations that will independently diverge genetically. We therefore expect to see a similar phylogenetic pattern for taxa other than the snapping shrimp. 34. B 35. It should be sympatric with its closest relative. We should be able to demonstrate that there have not been opportunities for allopatry over the period since the two species started to diverge. Fish in crater lakes meet these criteria for sympatric speciation: There Page 35
36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 52. 53. 54. 55. 56. 57. 58. 59. 60. 61. 62. 63. 64. 65. 66. 67. 68. 69. 70. 71. 72. 73. 74. 75.
is a monophyletic radiation of fish in the lake, which is of limited area and deep (and therefore unlikely, even in relatively dry periods, to have dried out, yielding allopatric populations in separate lake-floor ponds). Island endemics are another example: if we can demonstrate that the two taxa are each other's closest relatives and there is no nearby land on which speciation could have occurred allopatrically. Example: palm trees on Lord Howe Island off Australia. B A D C D C B C C B A B C B A B B C A B E E D A C D B B C E B D A B B C B B A B Page 36
76. 77. 78. 79. 80. 81. 82. 83. 84. 85. 86. 87. 88. 89. 90. 91. 92. 93. 94. 95. 96. 97. 98. 99. 100. 101. 102. 103. 104. 105. 106. 107. 108. 109. 110. 111. 112. 113. 114. 115. 116. 117. 118. 119.
C B B A B The combination of the randomness of mutation and the fixation of mutation results in speciation being largely a stochastic process. B B A B A A C D E A A B D E B A C C B C A A C B B A A B B D A Mutation. The changes will probably not be identical because mutations arise randomly. So the odds that changes will be identical in each population are extremely low. E A B D A B
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120. 121. 122. 123. 124. 125. 126. 127. 128. 129. 130. 131. 132. 133. 134.
B B C B B C C B B A A E A A D
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