24
Species and Their Formation
TEST FILE QUESTIONS
Fill in the Blank
1. The process by which one evolutionary unit splits into two units which thereafter
evolve as distinct lineages is known as _______.
Answer: speciation
2. _______ occurs when one species evolves into two daughter species after a physical
barrier to movement develops within its range.
Answer: Geographic speciation
3. Two populations that are _______ are said to belong to different species.
Answer: reproductively isolated
4. The offspring of genetically dissimilar parents, such as adults from two geographically
isolated populations, are called _______.
Answer: hybrids
5. _______ are factors that reduce the possibility of interbreeding between geographically
isolated populations that somehow have come into contact.
Answer: Isolating mechanisms
6. _______ isolating mechanisms prevent the formation of a zygote, thus reducing the
probability that hybrids will be formed.
Answer: Prezygotic
7. Once fertilization between isolated populations has occurred, _______ isolating
mechanisms may prevent the hybrids from surviving.
Answer: postzygotic
8. A common means of sympatric speciation is _______, in which the number of
chromosomes is multiplied.
Answer: polyploidy
9. The fossil record and current distributions of organisms reveal that some species or
groups have given rise to a large number of daughter species, a phenomenon called
_______.
Answer: evolutionary radiation
10. A factor promoting cohesion of species is _______, the movement of individuals so
Answer: gene flow
11. Two hybrid species of sunflowers, Tragopogon mirus and T. miscellus, have four sets
of chromosomes; this condition is called _______.
Answer: tetraploidy
12. Subdivision of a gene pool when members of the daughter species are not
geographically separated is called _______.
Answer: sympatric speciation
13. Organisms that are found only in one specific area are considered _______ to that
area.
Answer: endemic
Multiple Choice
1. Evolutionary biologists believe that all the species present today, along with all the
species that lived in the past, are descended from
a. a single ancestral species.
b. thousands of different origins.
c. one ancestral species per kingdom.
d. one ancestral species per phylum.
e. two or three ancestral species per kingdom.
Answer: a
2. Ernst Mayr’s definition of species states that species are groups of _______
interbreeding natural populations that are _______ isolated from each other.
a. actually; reproductively
b. potentially; reproductively
c. actually or potentially; reproductively
d. actually or potentially; geographically
e. potentially; geographically
Answer: c
3. Ernst Mayr’s definition of species does not include
a. groups that actually or potentially interbreed.
b. evolutionary units evolving separately from other units.
c. gene exchange.
d. members in a single geographic location.
e. groups that are reproductively separated from other groups.
Answer: d
4. The phrase “natural population” is important to the definition of species because
a. if two populations interbreed only in captivity, they are members of the same species.
b. if two populations co-occur but do not interbreed in nature, they are separate species.
c. if two populations do not co-occur, they must be different species because they cannot
interbreed.
d. if two populations can potentially interbreed, they are different species.
e. if two populations interbreed for the first time, their offspring form a new species.
Answer: b
5–8. Match the following descriptions of speciation with the appropriate terms from the
list below. Terms may be used once, more than once, or not at all.
a. geographic speciation
b. sympatric speciation
c. polyploidy
5. Two species of Japanese ladybird beetles occur in the same area. Epilachnea niponica
feeds on thistles, and Epilachnea yasutomii feeds on other plants that grow among
thistles. Adults of both species feed and mate on their own host plant. The two species
hybridize in the laboratory, but not in nature. Although we cannot be sure which process
actually produced speciation in this case, it is likely the two separate species are a result
of _______.
Answer: b
6. If the number of chromosomes of a species of lizard were to double (perhaps through
an error in meiosis), resulting in female offspring that could produce young from
unfertilized eggs, we would say speciation had occurred through _______.
Answer: c
7. The red tubular-flowered gilias of western North America are a group of species living
in the Mojave Desert. Originally considered to be a single species, the group now
contains five species: three diploids and two tetraploids (having four sets of
chromosomes). These five species, which are similar in appearance and sterile in all
interspecific mating combinations, are an example of _______.
Answer: c
8. Different populations of platyfish live in the rivers of eastern Mexico. The
subpopulations living in different streams have been diverging since an ancestral
platyfish colonized all the streams. Some subpopulations have diverged so much that they
cannot interbreed and produce viable offspring with individuals from other
subpopulations. Thus, these populations of platyfish exist at various stages in the process
of _______.
Answer: a
9. Which of the following factors probably was not important in the formation of the 14
species of Darwin’s finches on the Galápagos Islands?
a. Geographical isolation from the mainland
b. Polyploidy
c. Different habitats on the different islands
d. Geographical isolation of one island from another
e. Different food supplies on the different islands
Answer: b
10. Which of the following would not result in reproductive isolation between two
populations that are reunited following geographic isolation?
a. The two populations produce successful hybrids.
c. There are physiological differences between the two populations so that they cannot
produce viable offspring.
d. Members of one population do not find members of the other population attractive as
e. The two populations have different courtship behaviors.
Answer: a
11. Which of the following is a postzygotic isolation mechanism?
a. Temporal isolation
b. Behavioral isolation
c. Reduced viability of hybrids
d. Variation in mating pheromones
e. Differences in courtship behavior
Answer: c
a. Abnormal meiosis following fertilization
b. Infertile hybrids
c. Reduced viability of hybrids
d. Abnormal mitosis following fertilization
e. Variation in mating pheromones
Answer: e
13. _______ involves the subdivision of a gene pool even though members of the
daughter species overlap in their range during the speciation process. Often this is
accomplished by a multiplication of the number of chromosomes.
a. Polyploidy
b. Hybrid zonation
c. Sympatric speciation
d. Geographic speciation
e. None of the above
Answer: c
14. Which of the following is not true of polyploidy?
a. Polyploidy is more common in animals than in plants.
b. Many species of flowering plants arose by polyploidy.
c. Animals that speciate by polyploidy are often parthenogenetic.
d. Polyploidy can create new species quickly if the polyploid individuals can selffertilize.
e. Polyploid siblings are capable of reproducing with one another.
Answer: a
15. Which mode of speciation is thought to be most important in speciation of most
organisms?
a. Polyploidy
b. Hybrid zonation
c. Sympatric speciation
d. Geographic speciation
e. All of the above
Answer: d
16. Which of the following is not true of the genetics of speciation?
a. Sympatric species need not have diverged very much from each other genetically.
b. Speciation in Drosophila has not involved major reorganization of the genome.
c. Species that show a great deal of morphological variation may be relatively similar
genetically.
d. Gene flow is important in the creation of new species.
e. Differences between closely related species occur due to the same mechanisms that
operate within species.
Answer: d
17. Rapid speciation is thought to occur among animals with complex behavior patterns
because
a. the timing of reproduction is behaviorally mediated.
b. behavioral differences usually reflect physiological differences.
c. those organisms have difficulty identifying members of their own species and often
mate with members of other species.
d. those organisms make sophisticated discriminations among potential mates.
e. those organisms find mates more
Answer: d
18. The deer mouse, Peromyscus maniculatus, is the most widely distributed small
mammal in North America. It varies greatly according to its geographical location,
especially in coat color, tail length, and foot length. Where would you expect deer mice
to be relatively uniform?
a. In mountainous areas, where environmental conditions change dramatically from place
to place
b. On islands, where populations are isolated
c. Over large areas where there is little topographical or
Answer: c
19. Antelope in Africa went through a burst of speciation 2.5–2.9 million years ago. What
was the likely trigger of the speciation event?
a. Continental drift
b. Genetic drift
c. A change in the gene pool
d. A change in climate
e. Reproductive incompatibility
Answer: d
20. Which of the following is a reason that evolutionary radiation is likely to occur on
islands?
a. Islands may have relatively few plant and animal groups and thus present more
ecological opportunities than the continents do.
b. There are many more species on islands than on the continents.
c. Many organisms disperse easily over oceans.
d. Islands have more diverse habitats than continents do.
e. Islands tend to have more favorable habitats than continents, due to the moderating
effects of the oceans.
Answer: a
21. The Hawaiian Islands are useful for studying evolutionary radiation because they are
very isolated. Which of the following is not true of the biota of these islands?
a. More than 90 percent of the plant species are endemic.
b. Several groups of flowering plants are more diverse on these islands than their
counterparts are on the mainland.
c. There are no endemic amphibians on these islands.
d. There are no endemic reptiles on these islands.
e. There are no endemic mammals on these islands.
Answer: e
22. Which of the following is the hypothesized sequence of events in geographic
speciation?
a. Geographic barrier, reproductive isolation, genetic divergence
b. Geographic barrier, genetic divergence, reproductive isolation
c. Genetic divergence, geographic barrier, reproductive isolation
d. Genetic divergence, reproductive isolation, geographic barrier
e. Reproductive isolation, genetic divergence, geographic barrier
Answer: b
23. Mules are the offspring of parents of two different species, a horse and a donkey.
These hybrids exhibit
a. polyploidy.
b. a shortened lifespan.
c. behavioral isolation.
d. reduced viability.
e. sterility.
Answer: e
24. The modern polar bear species evolved from ancestral bear populations in southern
Alaska that became separated by glaciers from bear populations in the rest of North
America. This type of event is called
a. allopatric speciation.
b. temporal isolation.
c. mechanical isolation.
d. sympatric speciation.
e. None of the above
Answer: a
25. A situation in which two very similar animal species have overlapping distributions is
most likely the result of
a. allopatric speciation followed by range expansion.
b. sympatric speciation due to polyploidy.
c. convergent evolution of unrelated species.
d. mechanical isolation between the two species.
e. None of the above
Answer: a
26. Which of the following is not true of a hybrid zone?
a. It occurs where two different populations come into contact.
b. It may shift in location due to environmental changes.
c. Its habitat may differ from that favored by the
d. It may disappear if isolating mechanisms develop.
e. It may occur among animals, but it does not occur among plants.
Answer: e
27. American and European sycamores have been isolated from each other for at least 20
million years, but they are morphologically very similar and can form fertile hybrids.
According to Ernst Mayr’s definition of species, these sycamores should belong to
_______ species because they _______.
a. different; are geographically isolated
b. different; lack the opportunity to interbreed in nature
c. different; they are evolving separately
d. the same; are morphologically similar
e. the same; are capable of forming fertile offspring
Answer: e
28. Ginkgo trees occur in Asia and North America. Despite their geographic separation
by the Pacific Ocean, biologists consider them the same species. What aspect of Ernst
Mayr’s definition of species accounts for this?
a. They are reproductively isolated.
b. They are potentially capable of exchanging genes.
c. They are exchanging genes across the ocean.
d. They have different evolutionary ancestries.
e. They have formed a large hybrid zone.
Answer: b
29. Why are biological species not always equivalent to taxonomic species?
a. Taxonomic species are based on appearance, not reproductive behavior.
b. Taxonomic species are based on reproductive behavior, not appearance.
c. Biological species are based on appearance, not reproductive behavior.
d. Biological species are based on genetic information; taxonomic species are based on
ecological
e. None of the above
Answer: a
genes?
a. Allopatric
b. Sympatric
c. Polyploidy
d. Behavioral isolation
e. None of the above
Answer: a
31. Six platyfish with different tail spotting patterns live in eastern Mexico. Five of them
can interbreed and produce fertile offspring. One of them cannot interbreed with the other
five. What can you conclude about these platyfish?
a. They all belong to the same biological species.
b. They each are a different biological species.
c. There are two biological species in the example above.
d. There is not enough data given to draw a conclusion.
e. There are six biological species in the example above.
Answer: c
32. The progeny of genetically dissimilar parents are
a. infertile.
b. fertile.
c. hybrids.
d. mutants.
e. hermaphrodites.
Answer: c
33. If two genetically differentiated populations reestablish contact and the resulting
hybrid progeny are successful and reproduce with other members of the two populations,
what will probably happen?
a. Speciation will occur.
b. Genetic differences will increase between the
c. Reproductive isolation will occur.
d. The two populations will amalgamate; no new species will form.
e. Two new species will form.
Answer: d
34. If two genetically differentiated populations reestablish contact and the resulting
hybrid progeny are not as successful in reproduction as the members of the two parental
populations, what will probably happen?
a. Reproductive isolation will occur.
b. A stable hybrid zone will form.
c. The two populations will amalgamate; no new species will form.
d. The populations will become genetically identical.
e. Two new species will form.
Answer: a
35. Which form of reproductive isolation occurs between a horse and donkey when they
mate and produce a mule?
a. Prezygotic isolation
b. Abnormal zygote formation
c. Hybrid infertility
d. Hybrid vigor
e. Hybrid fertility
Answer: c
36. Which of the following modes of speciation can occur most quickly?
a. Allopatric
b. Prezygotic isolation
c. Sympatric
d. Dyspatric
e. Adaptive radiation
Answer: c
37. Because there are no physical barriers separating the species, many biologists believe
that speciation of host-specific insects occurs by
a. sympatric speciation.
b. hybrid infertility.
c. allopatric speciation.
d. hybridization.
e. prezygotic isolation.
Answer: a
38. What is the most important factor promoting the cohesion of a species?
a. Mutation
b. Natural selection
c. Gene flow
d. Genetic drift
e. Reproduction
Answer: c
39. Behavioral complexity and short generation time will tend to _______ the process of
speciation.
a. accelerate
b. decelerate
c. have no effect on
d. obscure
e. threaten
Answer: a
40. Some groups or species have given rise to large numbers of daughter species. This
phenomenon is known as
a. sympatric speciation.
b. hybridization.
c. evolutionary radiation.
d. gene flow.
e. evolution.
Answer: c
41. Which group of organisms has the highest prevalence of sympatric speciation?
a. Mammals
b. Insects
c. Plants
d. Fungi
e. Bacteria
Answer: c
42. When individuals from one population disperse to a new, geographically isolated
location and mate, the eventual result may be the formation of a new species. Such an
outcome is called a _______ event.
a. foundation
b. founder
c. radiative
d. gene flow
e. hybridization
Answer: b
43. A species that is found only in a certain area of the planet and nowhere else is called
a. endangered.
b. endemic.
c. extinct.
d. emetic.
e. exotic.
Answer: b
44. Which of the following is not true of ecology and the rate of speciation?
a. Speciation rates are correlated with the diets of mammals.
b. Speciation rates are not related to birth rates.
c. Speciation rates differ markedly in the fossil record.
d. Speciation rates are consistent across all organisms that have been studied so far.
e. Speciation rates are higher among animal species with more complex behavior patterns
than they are among animals with simple behavior patterns.
Answer: d
a. are isolated from other land masses.
b. are geologically very young.
c. have very low speciation rates.
d. are all ecologically similar.
e. always are inhabited by small numbers of species.
Answer: a
46. The adaptive radiation of Hawaiian silverswords has demonstrated what fact about
speciation?
a. Major morphological changes can be produced by small genetic changes.
b. Major morphological changes are produced only by large-scale genetic changes.
c. Many different silversword ancestors colonized Hawaii.
d. The Hawaiian silverswords are not distinct species.
e. Plant speciation always requires polyploidy.
Answer: a
47. Of the following reproductive isolating mechanisms, which one is the most efficient
at preventing waste of reproductive effort?
a. Hybrid inviability
b. Hybrid sterility
c. Gamete incompatibility
d. Prezygotic isolation
e. Hybrid cross-reproduction
Answer: d
48. Which mode of speciation is most prevalent among larger animals?
a. Geographic
b. Parapatric
c. Sympatric
d. Polyploidy
e. Genetic drift
Answer: a
49. Which of the following is not true of speciation?
animals with simpler behaviors.
c. Members of the same species can live on separate continents.
d. Speciation is more rapid on island archipelagos such as Hawaii and the Galápagos than
it is on the continents.
e. Sympatric speciation is the most common type among animals.
Answer: e
50. The family Asteraceae contains several genera found on the Hawaiian islands. There
is very little genetic variation among them, and they are thought to have evolved from a
single ancestral species. What is responsible for the large morphological differences?
a. Each island has a unique environment to which the plants have adapted.
c. Birds traveling between islands carried different types of seeds that started the plant
growth.
es.
e. Both c and d
Answer: a
51. Populations (such as blue and snow geese) that occasionally interbreed and form
hybrid zones
a. cannot be different species.
b. often result in evolutionary radiation.
c. can maintain species differences.
d. have little geographic variation.
e. will produce polyploid offspring.
Answer: c
52. Why is it so difficult to obtain evidence supporting sympatric speciation?
a. Sympatric speciation always takes a very long time to occur.
b. Sympatric speciation always involves polyploidy.
c. It is hard to distinguish true sympatric speciation from allopatric speciation that
occurred in the recent past.
d. It is impossible to show genetic differences in sympatric speciation.
e. Sympatric speciation is a rare event.
Answer: c
53. Fertile species produced from asexual reproduction of tetraploid individuals are
considered
a. diploid.
b. polyploid.
c. paraploid.
d. allopolyploid.
e. mutants.
Answer: d
STUDY GUIDE QUESTIONS
Knowledge and Synthesis Questions
1. Select all the correct answers that complete the following sentence: It is difficult to
apply the biological species concept to groups of organisms that
a. are asexual.
b. produce hybrids only in captivity.
c. show little morphological diversity.
d. exist only in the fossil record.
2. Which of the following statements about allopatric speciation is not true?
a. Allopatric speciation can sometimes involve small populations.
b. Allopatric speciation only occurs in species that are widely distributed.
c. Allopatric speciation always involves a physical barrier that interrupts gene flow.
d. Allopatric speciation can sometimes involve chance events.
3. A long, narrow hybrid zone exists between the ranges of the fire-bellied toad and the
yellow-bellied toad in Europe. Which of the following is a factor contributing to the
persistence of this zone?
a. Reinforcement strengthens the prezygotic barriers between the two species.
b. Hybrid offspring have the same fitness as nonhybrid offspring.
c. Both species travel long distances over the course of their lives.
d. Individuals from outside the hybrid zone regularly move into the hybrid zone.
4. Which type of speciation is most common among flowering plants?
a. Geographic
b. Sympatric
c. Allopatric
5. Which of the following would not be considered an example of a prezygotic
reproductive isolating mechanism?
a. One bird species forages in the tops of trees for flying insects while another forages on
the ground for worms and grubs.
b. The males of one species of moth cannot detect and respond to the sex attractant
chemicals produced by the females of another species.
c. Sperm of one species of sea urchin are unable to penetrate the egg plasma membrane
of another species.
d. Mosquitoes of one species are active in foraging and searching for mates at dusk,
whereas those of another species are active at dawn.
6. Which of the following factors would not be expected to increase the rate of speciation
in a group of organisms?
a. Fragmentation of populations
b. Poor dispersal ability
c. High birthrates
d. Increased behavioral complexity
7. Which of the following is not a suggested reason for the evolutionary radiation of
silverswords on the Hawaiian archipelago?
a. Water is an effective barrier for many organisms.
b. Because islands are small compared with mainland areas, you would expect more
species to develop there.
c. Competition is frequently reduced on islands.
d. More ecological opportunities exist on islands that have not been colonized by many
species.
8. Studies of species of Hawaiian Drosophila show that
a. sympatric speciation via polyploidy is common in insects.
b. few genes need to be involved in establishing reproductive isolation.
c. species with nonoverlapping ranges can be very similar.
d. a geographic barrier is not always necessary for the establishment of reproductive
isolation.
9. Which of the following statements about speciation is not true?
a. A small founding population can be involved in speciation.
b. Speciation always involves interruption of gene flow between different groups of
organisms.
c. The rate of speciation can vary for different groups of organisms.
d. Speciation cannot occur in a single generation.
10. Which of the following observations constitutes conclusive evidence that two
overlapping populations that had been geographically separated have not diverged into
distinct species?
a. Matings between members of the two populations produce viable hybrids.
b. A stable hybrid zone exists where their ranges overlap.
c. Interbreeding is common between members of the two populations.
d. None of the above
Answers
Knowledge and Synthesis Answers
1. a and d. The key criterion of a biological species is that its members be reproductively
isolated from other such groups. This criterion is impossible to evaluate in asexual and
fossil species.
2. b. A wide distribution is not a requisite for allopatric speciation.
3. d. These toads provide an example of related species in which reinforcement does not
strengthen prezygotic barriers, even though hybrid offspring are only half as fit as
nonhybrid offspring. The reason for this is that toads from outside the hybrid zone (not
subject to the selective pressure against hybridizing) regularly move into the hybrid zone
and mate with members of the other species. The hybrid zone remains narrow because
toads do not travel long distances; natural selection removes hybrids from the population
before they can disperse very far.
4. b. Sympatric speciation is most common among flowering plants. It has been estimated
that about 70 percent of all flowering plant species are polyploid.
5. a. Provided that the two species are active in the same locality at the same time, a
difference in the habitat in which they forage would not in itself be a barrier to
interbreeding (though seeking mates in different habitats might well be a barrier to
interbreeding). All of the other choices describe reproductive barriers that would act prior
to fertilization.
6. c. Birthrates per se do not seem to affect the rate of speciation in organisms. All other
factors have been shown to increase speciation rates in the lineages of some organisms.
7. b. Actually, biogeographers have found that larger land masses tend to have more
species than smaller land masses, so you might expect the reverse effect.
8. b. Studies of the Hawaiian Drosophila show that these species have only slight genetic
differences, despite being morphologically diverse.
9. d. New species formed by polyploidy can arise in a single generation.
10. d. Interbreeding, production of viable hybrids, and establishment of a hybrid zone do
not necessarily mean that speciation is not complete. If, on the other hand, the hybrids
were successful, fertile, and bred freely with members of both original populations, their
gene pools would merge, and you would conclude that speciation had not taken place.
TEXTBOOK SELF QUIZ QUESTIONS
1. A species is a group of
a. actually interbreeding natural populations that are reproductively isolated from other
such groups.
b. potentially interbreeding natural populations that are reproductively isolated from other
such groups.
c. actually or potentially interbreeding natural populations that are reproductively isolated
from other such groups.
d. actually or potentially interbreeding natural populations that are reproductively
connected to other such groups.
e. actually interbreeding natural populations that are reproductively connected to other
such groups.
2. Allopatric speciation may happen when
a. continents drift apart and separate previously connected lineages.
b. a mountain range separates formerly connected populations.
c. different environments on two sides of a barrier cause populations to diverge.
d. the range of a species is separated by loss of intermediate habitat.
e. all of the above
3. Finches speciated in the Galápagos Islands because
a. the Galápagos Islands are not far from the mainland.
b. the Galápagos Islands are arid.
c. the Galápagos Islands are small.
d. the islands of the Galápagos Archipelago are sufficiently isolated from one another that
there is little migration among them.
e. the islands of the Galápagos Archipelago are close enough to one another that there is
considerable migration among them.
4. Which of the following is not a potential prezygotic reproductive barrier?
a. Temporal segregation of breeding seasons
b. Differences in chemicals that attract mates
c. Hybrid infertility
d. Spatial segregation of mating sites
e. Sperm cannot survive in female reproductive tracts
5. A common means of sympatric speciation is
a. polyploidy.
b. hybrid infertility.
c. temporal segregation of breeding seasons.
d. spatial segregation of mating sites.
e. imposition of a geographic barrier.
6. Sympatric species are often similar in appearance because
a. appearances are often of little evolutionary significance.
b. the genetic changes accompanying speciation are often small.
c. the genetic changes accompanying speciation are usually large.
d. speciation usually requires major reorganization of the genome.
e. the traits that differ among species are not the same as the traits that differ among
individuals within species.
7. Narrow hybrid zones may persist for long times because
a. hybrids are always at a disadvantage.
b. hybrids have an advantage only in narrow zones.
c. hybrid individuals never move far from their birthplaces.
d. individuals that move into the zone have not previously encountered individuals of the
other species, so reinforcement of isolating mechanisms has not occurred.
e. Narrow hybrid zones are artifacts because biologists generally restrict their studies to
contact zones between species.
8. Which statement about speciation is not true?
a. It always takes thousands of years.
b. It often takes thousands of years, but may happen within a single generation.
c. Among animals, it usually requires a physical barrier.
d. Among plants, it often happens as a result of polyploidy.
e. It has produced the millions of species living today.
9. Speciation is often rapid within lineages in which species have complex behavior
because
a. individuals of such species make fine discriminations among potential mating partners.
b. such species have short generation times.
c. such species have high reproductive rates.
d. such species have complex relationships with their environments.
e. none of the above
10. Evolutionary radiations
a. often happen on continents, but rarely on island archipelagos.
b. characterize birds and plants, but not other taxonomic groups.
c. have happened on continents as well as on islands.
d. require major reorganizations of the genome.
e. never happen in species-poor environments.
11. Speciation is an important component of evolution because it
a. generates the variation upon which natural selection acts.
b. generates the variation upon which genetic drift and mutations act.
c. enabled Charles Darwin to perceive the mechanisms of evolution.
d. generates the high extinction rates that drive evolutionary change.
e. has resulted in a world with millions of species, each adapted for a particular way of
life.
Answers
1. c
2. e
3. d
4. c
5. a
6. b
7. d
8. a
9. a
10. c
11. e
ONLINE QUIZ QUESTIONS
1.The biological species concept states that
a.species are groups of potentially interbreeding natural populations which are
reproductively available to other such groups.
b.species are groups of actually interbreeding populations which are reproductively
isolated from other such groups.
c.species are groups of actually or potentially interbreeding natural populations which are
reproductively isolated from other such groups.
d.species are groups of actually interbreeding natural populations which are
reproductively available to other such groups.
e.species are groups of potentially interbreeding populations which are reproductively
isolated from other such groups.
Answer: c
2.Anagenesis is
a.a continuous change in a single lineage of organisms.
b.the formation of two species by the splitting of one evolutionary lineage.
c.the formation of a new species by the coming together of two evolutionary lineages.
d.the reduction of two lineages by the extinction of one of them.
e.the formation of new species by the reclassification of a group.
Answer: a
3.Which barrier is not one that can cause allopatric speciation in the given population?
a.Dry land; aquatic organisms
b.A forest; terrestrial and aquatic organisms
c.A lake; terrestrial organisms
d.An ocean; terrestrial organisms
e.Mountains; terrestrial and aquatic organisms
Answer: b
4.From one ancestral finch, how many species of Darwin's finches have been found?
a.2
b.6
c.9
d.14
e.18
Answer: d
5.Which of the following is not true about prezygotic reproductive barriers?
a.Sperm of one species may not attach to the egg of another species because the eggs do
not release the appropriate chemicals.
b.Individuals of a species may reject individuals of other species as mating partners.
c.Differences in sizes and shapes of reproductive organs may prevent the union of
gametes from different species.
d.Organisms have mating periods that are as long as few days or weeks.
e.Individuals of different species may select different places in the environment in which
to live.
Answer: d
6.An autopolyploid individual originates when cells that are normally diploid
accidentally duplicate their chromosomes, resulting in a
a.haploid.
b.diploid.
c.triploid.
d.tetraploid.
e.quintploid.
Answer: c
7.Hybrid zones
a.are poor natural laboratories for the study of speciation.
b.contain recombinant individuals resulting from many generations of hybridization.
c.contain offspring of crosses between hybrid and purebred individuals.
d.can be wide and stable for long periods of times.
e.can be short and narrow.
Answer: B
8.Which statement about speciation rates is true?
a.Animals with complex behavior are unlikely to form new species at a high rate because
they make indiscriminate choices among mating partners.
b.Individuals of species with poor dispersal abilities are likely to establish new
populations.
c.The changes in gene pools that are often inhibited when a population passes through a
bottleneck may prevent new adaptations.
d.Changes in climate may increase populations of species that live in formerly continuous
habitats.
e.The larger the number of species in a lineage, the larger the number of opportunities for
new species to form.
Answer: e
9.Evolutionary radiations occur on islands and not on continents because
a.continents cannot support the rapid increase in population.
b.islands have many plant and animal groups that can be found on the mainland.
c.the ecological opportunities that exist on continents are not as good as those on islands.
d.islands lack many of the plant and animal groups found on the mainland.
e.continents are too large.
Answer: d
10.African antelopes experienced a burst of speciation and extinction due to
a.hunters.
b.an equivalent increase and decrease in the predator population.
c.Africa's climate changing from warm and wet to cool and dry.
d.Africa's climate changing from hot and dry to cool and wet.
e.disease.
Answer: e
11.Speciation is an important component of evolution because it
a.generates the variation upon which natural selection acts.
b.generates the variation upon which genetic drift and mutations act.
c.enabled Charles Darwin to perceive the mechanisms of evolution.
d.generates the high extinction rates that drive evolutionary change.
e.has resulted in a world with millions of species, each adapted for a particular way of
life.
Answer: e
11.Speciation is an important component of evolution because it
a. generates the variation upon which natural selection acts.
b. generates the variation upon which genetic drift and mutations act.
c. enabled Charles Darwin to perceive the mechanisms of evolution.
d. generates the high extinction rates that drive evolutionary change.
e. has resulted in a world with millions of species, each adapted for a particular way of
life.
Answer: e
12.Total genetic isolation by geographic separation as seen in the case of rodents
transferring plant seeds to a neighboring valley is an example of
a. parapatric speciation.
b. allopatric speciation.
c. sympatric speciation.
Answer: b
13.An organism gaining an extra number of chromosomes, such as in polyploidy, is
indicative of
a. parapatric speciation.
b. allopatric speciation.
c. sympatric speciation.
Answer: c
14.Reproductive isolation between adjacent organisms of a population is an example of
a. parapatric speciation.
b. allopatric speciation.
c. sympatric speciation.
Answer: a