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Chapter 22- origin of species test prep

Total questions: 72

Worksheet time: 36mins

Name
Class
Date
1.

Catastrophism, meaning the regular occurrence of geological or meteorological disturbances (catastrophes), was Cuvier's attempt to explain the existence of

a)

Evolution

b)

The fossil record

c)

uniformitarianism

d)

the origin of new species

e)

natural selection

2.

With what other idea of his time was Cuvier's theory of catastrophism most in conflict?

a)

Gradualism

b)

The fixity of species

c)

island biogeography

d)

Uniformitarianism

e)

The scala naturae

3.

What was the prevailing belief prior to the time of Lyell and Darwin?

a)

Earth is a few thousand years old, and populations are unchanging

b)

Earth is a few thousand years old, and populations gradually change

c)

Earth is millions of years old, and populations rapidly change

d)

Earth is millions of years old, and populations are unchanging

e)

Earth is millions of years old, and populations gradually change

4.

During a study session about evolution, one of your fellow students remarks, "The giraffe stretched its neck while reaching for higher leaves; its offspring inherited longer necks as a result." Which statement is most likely to be helpful in correcting this student's misconception?

a)

Characteristics acquired during an organism's life are generally not passed on through genes

b)

Spontaneous mutations can result in the appearance of new traits

c)

Only favorable adaptations have survival value

d)

Disuse of an organ may lead to its eventual disappearance

e)

If the giraffes did not have to compete with each other, longer necks would not have been passed on to the next generation

5.

Which of the following is the most accurate summary of Cuvier's consideration of fossils found in the vicinity of Paris?

a)

extinction of species yes; evolution of new species yes

b)

extinction of species no; evolution of new species yes

c)

extinction of species yes; evolution of new species no

d)

extinction of species no; evolution of new species yes

6.

In the mid-1900s, the Soviet geneticist Lysenko believed that his winter wheat plants, exposed to ever-colder temperatures, would eventually give rise to ever more cold-tolerant winter wheat. Lysenko's attempts in this regard were most in agreement with the ideas of

a)

Cuvier

b)

Hutton

c)

Lamarck

d)

Darwin

e)

Lyell

7.

Charles Darwin was the first person to propose

a)

that evolution occurs

b)

a mechanism for how evolution occurs

c)

that Earth is older than a few thousand years.

d)

a mechanism for evolution that was supported by evidence

e)

that population growth can outpace the growth of food resources

8.

Which of these conditions should completely prevent the occurrence of natural selection in a population over time?

a)

All variation between individuals is due only to environmental factors

b)

The environment is changing at a relatively slow rate

c)

The population size is large

d)

The population lives in a habitat where there are no competing species present

9.

Natural selection is based on all of the following except

a)

genetic variation exists within populations.

b)

the best-adapted individuals tend to leave the most offspring

c)

individuals who survive longer tend to leave more offspring than those who die young

d)

populations tend to produce more individuals than the environment can support

e)

individuals adapt to their environments and, thereby, evolve

10.

Which of the following represents an idea that Darwin learned from the writings of Thomas Malthus?

a)

Technological innovation in agricultural practices will permit exponential growth of the human population into the foreseeable future

b)

Populations tend to increase at a faster rate than their food supply normally allows

c)

Earth changed over the years through a series of catastrophic upheavals

d)

The environment is responsible for natural selection

e)

Earth is more than 10,000 years old

11.

Given a population that contains genetic variation, what is the correct sequence of the following events, under the influence of natural selection?

1. Well-adapted individuals leave more offspring than do poorly adapted individuals.

2. A change occurs in the environment.

3. Genetic frequencies within the population change.

4. Poorly adapted individuals have decreased survivorship.

a)

2 → 4 → 1 → 3

b)

4 → 2 → 1 → 3

c)

4 → 1 → 2 → 3

d)

4 → 2 → 3 → 1

e)

2 → 4 → 3 → 1

12.

A biologist studied a population of squirrels for 15 years. During that time, the population was never fewer than 30 squirrels and never more than 45. Her data showed that over half of the squirrels born did not survive to reproduce, because of both competition for food and predation. In a single generation, 90% of the squirrels that were born lived to reproduce, and the population increased to 80. Which inference(s) about this population might be true?

a)

1. The amount of available food may have increased

b)

2. The parental generation of squirrels developed better eyesight due to improved diet; the subsequent squirrel generation inherited better eyesight

c)

3. The squirrels of subsequent generations should show greater levels of genetic variation than previous generations, because squirrels that would not have survived in the past will now survive

d)

4. Three of the statements above are correct

e)

5. Two of the statements above are correct

13.

Which of the following must exist in a population before natural selection can act upon that population?

a)

1. genetic variation among individuals

b)

2. variation among individuals caused by environmental factors

c)

3. sexual reproduction

d)

4. Three of the responses are correct.

e)

5. Two of the responses are correct

14.

Which of Darwin's ideas had the strongest connection to Darwin having read Malthus's essay on human population growth?

a)

descent with modification

b)

variation among individuals in a population

c)

struggle for existence

d)

the ability of related species to be conceptualized in "tree thinking"

e)

that the ancestors of the Galápagos finches had come from the South American mainland

15.

If Darwin had been aware of genes, and of their typical mode of transmission to subsequent generations, with which statement would he most likely have been in agreement?

a)

If natural selection can change one gene's frequency in a population over the course of generations then, given enough time and enough genes, natural selection can cause sufficient genetic change to produce new species from old ones

b)

If an individual's somatic cell genes change during its lifetime, making it more fit, then it will be able to pass these genes on to its offspring

c)

If an individual acquires new genes by engulfing, or being infected by, another organism, then a new genetic species will be the result

d)

A single mutation in a single gene in a single gamete will, if perpetuated, produce a new species within just two generations

16.

The role that humans play in artificial selection is to

a)

determine who lives and who dies

b)

create the genetic variants, which nature then selects

c)

choose which organisms breed, and which do not

d)

train organisms to breed more successfully

e)

perform artificial insemination

17.

Currently, two extant elephant species (X and Y) are placed in the genus Loxodonta, and a third species (Z) is placed in the genus Elephas. Thus, which statement should be true?

a)

Species X and Y are not related to species Z

b)

Species X and Y share a greater number of homologies with each other than either does with species Z

c)

Species X and Y share a common ancestor that is still extant (in other words, not yet extinct)

d)

Species X and Y are the result of artificial selection from an ancestral species Z

e)

Species X, Y, and Z share a common ancestor, but nothing more can be claimed than this

18.

The rise of methicillin-resistant Staphylococcus aureus (MRSA) can be considered to be an example of artificial selection because

a)

humans purposefully raise MRSA in large fermenters in an attempt to make the bacteria ever-more resistant

b)

S. aureus is cultivated by humans to replenish the soil with nutrients

c)

humans synthesize methicillin and create environments in which bacteria frequently come into contact with methicillin

d)

Humans are becoming resistant to bacteria by taking methicillin

19.

In a hypothetical environment, fishes called pike-cichlids are visual predators of algae-eating fish (in other words, they locate their prey by sight). If a population of algae-eaters experiences predation pressure from pike-cichlids, which of the following is least likely to be observed in the algae-eater population over the course of many generations?

a)

selection for drab coloration of the algae-eaters

b)

selection for nocturnal algae-eaters (active only at night)

c)

selection for larger female algae-eaters, bearing broods composed of more, and larger, young

d)

selection for algae-eaters that become sexually mature at smaller overall body sizes

e)

selection for algae-eaters that are faster swimmers

20.

DDT was once considered a "silver bullet" that would permanently eradicate insect pests. Today, instead, DDT is largely useless against many insects. Which of these would have been required for this pest eradication effort to be successful in the long run?

a)

Larger doses of DDT should have been applied

b)

All habitats should have received applications of DDT at about the same time

c)

The frequency of DDT application should have been higher.

d)

None of the individual insects should have possessed genomes that made them resistant to DDT

e)

DDT application should have been continual

21.

Of the following anatomical structures, which is homologous to the bones in the wing of a bird?

a)

cartilage in the dorsal fin of a shark

b)

bones in the hind limb of a kangaroo

c)

chitinous struts in the wing of a butterfly

d)

bony rays in the tail fin of a flying fish

e)

bones in the flipper of a whale

22.

If two modern organisms are distantly related in an evolutionary sense, then one should expect that

a)

they live in very different habitats

b)

they should share fewer homologous structures than two more closely related organisms

c)

their chromosomes should be very similar

d)

they shared a common ancestor relatively recently

e)

they should be members of the same genus

23.

Structures as different as human arms, bat wings, and dolphin flippers contain many of the same bones, these bones having developed from very similar embryonic tissues. How do biologists interpret these similarities?

a)

1. by identifying the bones as being homologous structures

b)

2. by the principle of convergent evolution

c)

3. by proposing that humans, bats, and dolphins share a common ancestor

d)

4. Three of the statements above are correct.

e)

6. Two of the statements above are correct

24.

Over evolutionary time, many cave-dwelling organisms have lost their eyes. Tapeworms have lost their digestive systems. Whales have lost their hind limbs. How can natural selection account for these losses?

a)

Natural selection cannot account for losses, only for innovations

b)

Natural selection accounts for these losses by the principle of use and disuse

c)

Under particular circumstances that persisted for long periods, each of these structures presented greater costs than benefits

d)

The ancestors of these organisms experienced harmful mutations that forced them to find new habitats that these species had not previously used

25.

Which of the following pieces of evidence most strongly supports the common origin of all life on Earth?

a)

All organisms require energy

b)

All organisms use essentially the same genetic code

c)

All organisms reproduce

d)

All organisms show heritable variation

e)

All organisms have undergone evolution

26.

Logically, which of these should cast the most doubt on the relationships depicted by an evolutionary tree?

a)

None of the organisms depicted by the tree ate the same foods

b)

Some of the organisms depicted by the tree had lived in different habitats

c)

The skeletal remains of the organisms depicted by the tree were incomplete (in other words, some bones were missing)

d)

Transitional fossils had not been found

e)

Relationships between DNA sequences among the species did not match relationships between skeletal patterns

27.

Which of the following statements most detracts from the claim that the human appendix is a completely vestigial organ?

a)

The appendix can be surgically removed with no immediate ill effects

b)

The appendix might have been larger in fossil hominids

c)

The appendix has a substantial amount of defensive lymphatic tissue

d)

Individuals with a larger-than-average appendix leave fewer offspring than those with a below-average-sized appendix

e)

In a million years, the human species might completely lack an appendix

28.

Members of two different species possess a similar-looking structure that they use in a similar fashion to perform the same function. Which information would best help distinguish between an explanation based on homology versus one based on convergent evolution?

a)

The two species live at great distance from each other

b)

The two species share many proteins in common, and the nucleotide sequences that code for these proteins are almost identical

c)

The sizes of the structures in adult members of both species are similar in size

d)

Both species are well adapted to their particular environments

29.

Ichthyosaurs were aquatic dinosaurs. Fossils show us that they had dorsal fins and tails, as do fish, even though their closest relatives were terrestrial reptiles that had neither dorsal fins nor aquatic tails. The dorsal fins and tails of ichthyosaurs and fish are

a)

1. homologous

b)

2. examples of convergent evolution

c)

3. adaptations to a common environment

d)

4. Three of the responses above are correct

e)

5. Two of the responses above are correct

30.

Both ancestral birds and ancestral mammals shared a common ancestor that was terrestrial. Today, penguins (which are birds) and seals (which are mammals) have forelimbs adapted for swimming. What term best describes the relationship of the bones in the forelimbs of penguins and seals, and what term best describes the flippers of penguins and seals?

a)

homologous; homologous

b)

analogous; homologous

c)

homologous; analogous

d)

analogous; analogous

31.

What must be true of any organ that is described as vestigial?

a)

It must be analogous to some feature in an ancestor

b)

It must be homologous to some feature in an ancestor

c)

It must be both homologous and analogous to some feature in an ancestor

d)

It need be neither homologous nor analogous to some feature in an ancestor

32.

What is true of pseudogenes?

a)

They are composed of RNA, rather than DNA.

b)

They are the same things as introns

c)

They are unrelated genes that code for the same gene product

d)

They are vestigial genes

33.

It has been observed that organisms on islands are different from, but closely related to, similar forms found on the nearest continent. This is taken as evidence that

a)

island forms and mainland forms descended from common ancestors

b)

common environments are inhabited by the same organisms

c)

the islands were originally part of the continent

d)

the island forms and mainland forms are converging

e)

island forms and mainland forms have identical gene pools

34.

If one wanted to find the largest number of endemic species, one should visit which of the following geological features (assuming each has existed for several millions of years)?

a)

an isolated ocean island in the tropics

b)

an extensive mountain range

c)

a midcontinental grassland with extreme climatic conditions

d)

a shallow estuary on a warm-water coast

35.

A high degree of endemism is most likely in environments that are

a)

easily reached and heterogeneous

b)

isolated and heterogeneous

c)

isolated and homogeneous

d)

isolated and extremely cold

e)

easily reached and homogeneous

36.

About 13 different species of finches inhabit the Galápagos Islands today, all descendants of a common ancestor from the South American mainland that arrived a few million years ago. Genetically, there are four distinct lineages, but the 13 species are currently classified among three genera. The first lineage to diverge from the ancestral lineage was the warbler finch (genus Certhidea). Next to diverge was the vegetarian finch (genus Camarhynchus), followed by five tree finch species (also in genus Camarhynchus) and six ground finch species (genus Geospiza).

If the six ground finch species have evolved most recently, then which of these is the most logical prediction?

a)

They should be limited to the six islands that most recently emerged from the sea

b)

Their genomes should be more similar to each other than are the genomes of the five tree finch species

c)

They should share fewer anatomical homologies with each other than they share with the tree finches

d)

The chances of hybridization between two ground finch species should be less than the chances of hybridization between two tree finch species

37.

According to a 1999 study, the vegetarian finch is genetically no more similar to the tree finches than it is to the ground finches, despite the fact that it is placed in the same genus as the tree finches. Based on this finding, it is reasonable to conclude that the vegetarian finch

a)

is no more closely related to the tree finches than it is to the ground finches, despite its classification

b)

should be re-classified as a warbler finch

c)

is not truly a descendent of the original ancestral finch

d)

is a hybrid species, resulting from a cross between a ground finch and a tree finch

38.

A 14th species that descended from the original ancestral finch, the Cocos Island finch, is endemic to its namesake island, located 550 km off Costa Rica. The Cocos Island finch is genetically much more similar to the tree finches than is the vegetarian finch, yet it is classified in its own genus Pinarolaxias. Moreover, the Cocos Island finch and the vegetarian finch are the two finch species that are most genetically different from the ancestral Galápagos finch. Thus, if classification is to reflect evolutionary relationships, the vegetarian finch should

a)

remain in the genus Camarhynchus

b)

be switched from Camarhynchus to Certhidea

c)

be switched from Camarhynchus to Pinarolaxias

d)

be switched from Camarhynchus to Geospiza

e)

be placed in its own genus

39.

Which of the following is not an observation or inference on which natural selection is based?

a)

There is heritable variation among individuals

b)

Poorly adapted individuals never produce offspring

c)

Species produce more offspring than the environment can support

d)

Individuals whose characteristics are best suited to the environment generally leave more offspring than those whose characteristics are less well suited

e)

Only a fraction of an individual's offspring may survive

40.

Which of the following observations helped Darwin shape his concept of descent with modification?

a)

Species diversity declines farther from the equator

b)

Fewer species live on islands than on the nearest continents

c)

Birds can be found on islands located farther from the mainland than the birds' maximum nonstop flight distance

d)

South American temperate plants are more similar to the tropical plants of South America than to the temperate plants of Europe

e)

Earthquakes reshape life by causing mass extinctions

41.

Within six months of effectively using methicillin to treat S. aureus infections in a community, all new infections were caused by MRSA. How can this result best be explained?

a)

S. aureus can resist vaccines

b)

A patient must have become infected with MRSA from another community

c)

In response to the drug, S. aureus began making drug-resistant versions of the protein targeted by the drug

d)

Some drug-resistant bacteria were present at the start of treatment, and natural selection increased their frequency.

e)

The drug caused the S. aureus DNA to change

42.

The upper forelimbs of humans and bats have fairly similar skeletal structures, whereas the corresponding bones in whales have very different shapes and proportions. However, genetic data suggest that all three kinds of organisms diverged from a common ancestor at about the same time. Which of the following is the most likely explanation for these data?

a)

Humans and bats evolved by natural selection, and whales evolved by Lamarckian mechanisms

b)

Forelimb evolution was adaptive in people and bats, but not in whales

c)

Natural selection in an aquatic environment resulted in significant changes to whale forelimb anatomy

d)

Genes mutate faster in whales than in humans or bats

e)

Whales are not properly classified as mammals

43.

DNA sequences in many human genes are very similar to the sequences of corresponding genes in chimpanzees. The most likely explanation for this result is that

a)

humans and chimpanzees share a relatively recent common ancestor

b)

humans evolved from chimpanzees

c)

chimpanzees evolved from humans

d)

convergent evolution led to the DNA similarities

e)

humans and chimpanzees are not closely related

44.

When gene flow between two populations ceases, the potential for __________ exists

a)

Hybridization

b)

Fusion

c)

Speciation

d)

Sexual selection

e)

Sexual reproduction

45.

Bird guides once listed the myrtle warbler and Audubon's warbler as distinct species that lived side by side in parts of their ranges. However, recent books show them as eastern and western forms of a single species, the yellow-rumped warbler. Apparently, the myrtle warbler and Audubon's warbler __________.

a)

are almost identical in appearance

b)

live in the same areas

c)

have undergone coevolution

d)

successfully interbreed and produce fertile offspring

e)

are merging to form a single specie

46.

Imagine that part of a population of South American finches is blown by a storm onto an island far offshore and manages to survive and reproduce there for a period of 10,000 years. After that period, a climate change results in lower sea levels and the reconnection of the island with the mainland. Members of the formerly isolated island finch population can now interact freely with members of the original mainland population. Which observation would, by itself, lead you to conclude unequivocally that the island finch population had evolved into a distinct species, according to the biological species concept?

a)

Hybrid offspring of matings between individuals from the two populations do not look like either parent

b)

Individuals from the different populations sometimes mate with each other, but all of the resulting eggs are sterile

c)

Individuals from the different populations frequently direct courtship behavior toward members of the other population

d)

The preferred food of the island birds is quite different from the diet of mainland birds

e)

The island birds all have red feathers, but the mainland birds have green feathers

47.

Which condition is necessary for speciation to occur?

a)

sympatric speciation

b)

reproductive isolation

c)

adaptive radiation

d)

interbreeding among neighboring populations

e)

mass extinction

48.

Prezygotic barriers __________.

a)

are necessary in order for speciation to occur

b)

prevent donkeys and horses from mating

c)

prevent fertilization of gametes from members of closely related species

d)

prevent a hybrid zygote from developing into a viable, fertile adult

e)

only occur in asexual organisms

49.

Three species of frogs, Rana pipiens, Rana clamitans, and Rana sylvatica, all mate in the same ponds, but they pair off correctly because they have different calls. This is a specific example of a __________ barrier, called __________.

a)

prezygotic … behavioral isolation

b)

prezygotic … gametic isolation

c)

postzygotic … mechanical isolation

d)

postzygotic … hybrid breakdown

e)

prezygotic … temporal isolation

50.

Which reproductive barrier actually prevents individuals of closely related species from copulating successfully?

a)

gametic isolation

b)

hybrid sterility

c)

mechanical isolation

d)

hybrid breakdown

e)

reduced hybrid viability

51.

Two species of water lilies in the same pond do not interbreed because one blooms at night and the other during the day. The reproductive barrier between them is an example of __________.

a)

mechanical isolation

b)

ecological isolation

c)

temporal isolation

d)

temporal isolation

e)

gametic isolation

52.

Which of is an example of a postzygotic reproductive barrier?

a)

One species of frog mates in April, but another mates in May.

b)

Two pheasant species perform different courtship dances.

c)

The sperm of a marine worm can only penetrate eggs of the same species.

d)

One species of flower grows in forested areas, another in meadows.

e)

Two fruit flies of different species produce sterile offspring.

53.

There are two groups of pine trees that appear to be very similar phenotypically and genotypically. However, one releases pollen in January, when the female structures of that group are receptive, and one in March. What kind of reproductive barrier is this?

a)

reduced hybrid viability

b)

mechanical isolation

c)

temporal isolation

d)

gametic isolation

e)

a geographic barrier

54.

The phylogenetic species concept emphasizes __________.

a)

the ability to hybridize

b)

ecological niches

c)

phenotypic differences

d)

the evolution of reproductive isolation

e)

common ancestry

55.

Lake Victoria, in Africa, is home to a group of related fishes known as cichlids. Many of these fishes are similar in appearance but have different feeding habits. What is the best method for scientists to determine conclusively whether the fish are members of a population that has a lot of variation or members of entirely different species?

a)

Study the fossil record

b)

Observe the fish in their natural environment for possible instances of interbreeding leading to several generations of fertile offspring

c)

Compare DNA sequences, because the DNA of members of the same species should be identical

d)

Do studies on comparative anatomy, especially looking for homologous structures

e)

All of the choices must be performed to determine whether a single population or different species are present

56.

In practice, how do scientists distinguish most species?

a)

by using the ecological species concept

b)

by using the paleontological species concept

c)

by using the morphological species concept

d)

by using the phylogenetic species concept

e)

by using the biological species concept

57.

Which species concept defines a species as a set of organisms with a unique genetic history?

a)

biological species concept

b)

None of the choices is correct

c)

ecological species concept

d)

morphological species concept

e)

sexual species concept

58.

Sometimes two phenotypically different populations interbreed to a limited extent, so that it is difficult to determine whether they are clearly separate species. This is not a concern to scientists because this __________.

a)

supports the theory of punctuated equilibrium

b)

is quite rare

c)

may indicate that the formation of a new species is in progress

d)

happens only among plants, not among animals

e)

is true for almost every species

59.

Which organism is most likely to be subject to allopatric speciation?

a)

fruit flies on bananas and fruit flies on oranges

b)

whale populations of the same species located on opposite sides of the Atlantic Ocean

c)

bacteria in a hospital and bacteria in a nursery

d)

pine trees in Alaska and pine trees on the island of Madagascar

e)

mountain lions in the canyons of Wyoming and in the canyons of Utah

60.

Which evolutionary mechanism does not contribute to the process of allopatric speciation?

a)

genetic drift

b)

mutation

c)

natural selection

d)

gene flow

e)

All of the choices contribute to the process of allopatric speciation

61.

If a new species of plant is to be produced by means of allopolyploidy from two parental species that are 2n = 4 and 2n = 8, how many chromosomes would you expect in the somatic cells of the new species?

a)

6

b)

12

c)

24

d)

48

e)

None of the listed responses is correct

62.

A new species can arise in a single generation __________.

a)

if adaptive radiation occurs

b)

through geographic isolation

c)

if allopatric speciation occurs

d)

in a very large population spread over a large area

e)

if a change in chromosome number creates a reproductive barrier

63.

The Galápagos finches collected by Darwin are thought to have descended from a very small parent population. Different species of finches that are confined to only one or two islands most likely arose by __________.

a)

sympatric speciation

b)

polyploidy

c)

hybridization

d)

allopatric speciation

e)

gene flow

64.

In the case of the Lake Victoria cichlids, sympatric speciation has been shown to be driven, at least in part, by __________.

a)

postzygotic barriers

b)

habitat differentiation

c)

sexual selection

d)

mechanical isolation

e)

polyploidy

65.

In a hybrid zone, which would tend to lead to reinforcement?

a)

sexual selection

b)

reduced hybrid fertility

c)

reduced hybrid viability

d)

hybrid breakdown

e)

All of the choices are correct

66.

In the Lake Victoria cichlids, what appears to be contributing to fusion of different species?

a)

The viability of cichlid eggs is being reduced by water pollution

b)

Overfishing has wiped out intermediates

c)

Females have a difficult time visually selecting males of the same species in the murky, polluted water

d)

Extinctions are being caused by new viruses

e)

Murky, polluted water is causing reduced hybrid viability

67.

According to the punctuated equilibrium model of evolution, __________.

a)

the tempo of evolution consists of abrupt episodes of speciation among long periods of equilibrium

b)

fossils of organisms that existed during periods of stasis should be as abundant as those of organisms that existed during periods of rapid change

c)

polyploidy is not a mechanism of punctuated equilibrium

d)

isolated species changing over a few thousand generations represent graduated equilibrium, not punctuated equilibrium

e)

None of the choices is correct

68.

Comparison of human fossils with living humans seems to show that there have been no significant physical changes in Homo sapiens in 30,000 to 50,000 years. What might an advocate of punctuated equilibrium say about this?

a)

You would expect a lot of skeletal changes in that time period

b)

That is about how long we have been reproductively isolated

c)

It is impossible to see major internal changes by looking at fossils

d)

Lack of change is consistent with the punctuated equilibrium model

e)

It is about time for humans to undergo a burst of change

69.

What is the first thing that must happen in order for speciation to occur?

a)

A hybrid zone must be established

b)

Gene flow between populations must be interrupted

c)

One of the populations must become polyploid

d)

A catastrophic event must cause geographic separation of two populations

e)

The populations must become reproductively isolated

70.

How many genes must change in order to form a new species?

a)

1

b)

4

c)

11

d)

26

e)

There is no set number of genes or loci that produces a new species. Genetic and environmental factors interact

71.

The time interval between speciation events is typically __________.

a)

6.5 million years

b)

40 million years

c)

500,000 years

d)

4,000 years

e)

Times between speciation events vary widely and depend on generation times, causes of speciation, environmental factors, and chance

72.

Which of the following statements best describes theories?

a)

They are nearly the same things as hypotheses

b)

They are supported by, and make sense of, many observations

c)

They cannot be tested because the described events occured only once

d)

They are predictions of future events