1. Darwin originally defined evolution as _____. ( Overview ) Your Answer: descent with modification Correct. Darwin proposed that Earth's many species are descendants of ancestral species that differed from present-day species. 2. Which of the following is a key observation that must be explained in a unifying theory about life? ( Overview ) Your Answer: Evolution is based on descent with modification. Correct Answer: Many basic characteristics are shared by all living things. No. Darwin proposed descent with modification as a mechanism to produce the observed diversity of life. 3. Which of the following is an example of the process of evolution? ( Overview and Concept 22.3 ) Your Answer: the changes in organisms over time observed in the fossil record Correct Answer: predation No. This is an example of the pattern of evolution. 4. Which of the following is a true statement about Charles Darwin? ( Concept 22.1 ) Your Answer: He proposed natural selection as the mechanism of evolution. Correct. The proposal of a testable mechanism was a key point in the acceptance of his theory. 5. The scala naturae, or scale of nature, is based on the ideas of _____. ( Concept 22.1 )
Transcript
1. Darwin originally defined evolution as _____. ( Overview)
Your Answer:
descent with modification
Correct. Darwin proposed that Earth's many species are descendants of ancestral species that differed from present-day species.
2. Which of the following is a key observation that must be explained in a unifying theory about life? ( Overview)
Your Answer: Evolution is based on descent with modification.
Correct Answer:
Many basic characteristics are shared by all living things.
No. Darwin proposed descent with modification as a mechanism to produce the observed diversity of life.
3. Which of the following is an example of the process of evolution? ( Overview and Concept 22.3)
Your Answer: the changes in organisms over time observed in the fossil record
Correct Answer:
predation
No. This is an example of the pattern of evolution.
4. Which of the following is a true statement about Charles Darwin? ( Concept 22.1)
Your Answer:
He proposed natural selection as the mechanism of evolution.
Correct. The proposal of a testable mechanism was a key point in the acceptance of his theory.
5. The scala naturae, or scale of nature, is based on the ideas of _____. ( Concept 22.1)
Your Answer: Darwin
Correct Answer:
Aristotle
No. Darwin is best known for proposing natural selection as a mechanism of evolution.
6. At the time Darwin voyaged on HMS Beagle, the popularly accepted theory in Western culture that
explained the origin of Earth's plants and animals held that the various species _____. ( Concept 22.1)
Your Answer:
had been created by divine intervention a few thousand years before
Correct. Darwin's view of life contrasted sharply with the conventional paradigm of an Earth only a few thousand years old, populated by unchanging forms of life that had been individually made during a single week in which the Creator formed the entire universe.
7. Carolus Linneaus is considered to be the founder of _____ and _____. ( Concept 22.1)
Your Answer:
the binomial classification system; thought that resemblances among different species reflected the pattern of their creation
Correct. Although he is considered the founder of taxonomy, Linnaeus accepted the theory of creation.
8. The modern idea of extinction as a common occurrence in Earth's history was first proposed in the early 19th
century writings of _____. ( Concept 22.1)
Your Answer: Wallace
Correct Answer:
Cuvier
No. Wallace is best known for proposing natural selection independently of Charles Darwin.
9. Lyell's principle of uniformitarianism _______. ( Concept 22.1)
Your Answer:
strongly influenced Darwin's view of how living organisms could change over time.
Correct. Darwin embraced the idea of an old Earth and rejected the idea that living organisms had been specially created. He applied the idea of slow change to the evolution of organisms.
10.
At the time Charles Darwin sailed on HMS Beagle, _____. ( Concept 22.1)
Your Answer:
several biologists had proposed that species might change over time, but none had suggested a convincing mechanism that might cause the change
Correct. By the end of the 18th century, several naturalists had suggested that life evolved along with the evolution of Earth. An important facet of Darwin's work is the concept of natural selection as the cause of adaptive evolution.
11.
Because he was well aware of the effect his theory of evolution would have on the public and on the Church of England, Darwin delayed publishing his work for several decades while he gathered additional evidence.
Which of the following lines of evidence did he use to support his theory? ( Concept 22.2)
Your Answer: Artificial selection can produce organisms that differ markedly from their wild ancestors, and island species around the world all appear to be related to each other.
Correct Answer:
All species are capable of producing more offspring than the environment can support, and artificial selection can produce organisms that differ from their wild ancestors.
No. Darwin used the argument about artificial selection, but he observed that island species seemed to be related to organisms from the closest mainland.
12.
During his voyage around the world, Darwin was inspired to think about evolution by _____. ( Concept 22.2)
Your Answer:
all of the above
Correct. During his voyage on the HMS Beagle, Darwin was inspired to think about evolution by the writings of Lamarck, fossils, the adaptations of organisms like the Gálapagos finches, and the uniqueness of organisms.
13.
In Darwin's view of descent with modification _____. ( Concept 22.2)
Your Answer: environmental changes have no effect on the organisms living in that environment
Correct Answer:
natural selection can improve the match between an organism and its environment
No. A trait that is advantageous in one environment may be detrimental in another.
14.
What insight did Darwin gain from reading Thomas Malthus's essay on human suffering? ( Concept 22.2)
Your Answer: Population size usually remains relatively stable.
Correct Answer:
Organisms have the capacity to overreproduce.
No. This was not an insight he gained from reading Malthus. However, this is related to the correct answer.
15.
The breeding of plants and animals for particular traits by humans is called _____. ( Concept 22.2)
Your Answer: homology
Correct Answer:
artificial selection
No. Homology refers to organisms sharing traits based on common ancestry.
16.
During periods of rapid environmental change, what may happen to a species that was well-suited to the
former environment? ( Concept 22.2)
Your Answer: Individuals with particular traits that provide an advantage in the new environment will have higher reproductive success.
Correct Answer:
all of the above
No. This statement is true, but there is a better answer.
17.
The smallest unit that can evolve is a(n) _____. ( Concept 22.2)
Your Answer: genotype
Correct Answer:
population
No. This does not make sense.
18.
According to the theory of evolution, all of the different kinds of homologies—anatomical, molecular, and
embryological—should _____. ( Concept 22.3)
Your Answer: be completely independent of each other
Correct Answer:
produce similar patterns of evolutionary relatedness
No. This would not be expected if the organisms exhibiting such homologies were genetically related to each other.
19.
When they were first sold, aerosol insecticides were highly effective in killing flies and mosquitoes. Now, several decades later, a much smaller proportion of these insects die when sprayed. The reason fewer insects
die when they are sprayed is that _____. ( Concept 22.3)
Your Answer: none of the above
Correct Answer:
many mosquitoes today are descendants of mosquitoes with insecticide-resistant characteristics
No. One of the other choices is correct.
20.
A population of zooplankton is exposed to a small number of predatory fish that feed on the larger-sized (adult) zooplankton. Which of the following predictions would most likely occur based on the principles of
natural selection? ( Concept 22.3)
Your Answer: The zooplankton will become sexually mature at larger sizes.
Correct Answer:
Adult zooplankton will start to reach sexual maturity when they are still relatively small.
No. This is exactly the opposite of what one should predict.
21.
How did HIV become resistant to the drug 3TC? ( Concept 22.3)
Your Answer: The drug did not work in the way that the developers intended.
Correct Answer:
Some members of the virus population must have had a genetic variation that made them resistant to 3TC.
No. Think about the question in relation to natural selection.
22.
An important challenge to traditional (pre-1860) ideas about species was the observation that seemingly dissimilar organisms such as hummingbirds, humans, and whales have similar skeletal structures. This most
directly suggested to biologists that _____. ( Concept 22.3)
Your Answer: advantageous changes can be passed along to offspring
Correct Answer:
dissimilar organisms might have evolved from a distant, common ancestor
No. While true, this does not account for similarities among dissimilar organisms.
23.
Animals that possess homologous structures probably _____. ( Concept 22.3)
Your Answer: by chance had similar mutations independently in the past
Correct Answer:
evolved from the same ancestor
No. It is unlikely that two unrelated species would experience similar mutations.
24.
On an evolutionary tree _______. ( Concept 22.3)
Your Answer:
homologous characteristics form a nested pattern
Correct. We would expect this pattern to form through descent with modification.
25.
The approach to evolution that involves the study of similar structures that appear during the development of
different organisms is known as the study of _____. ( Concept 22.3)
Your Answer: cladistics
Correct Answer:
embryological homologies (comparative embryology)
No. This is the study of taxonomic classifications based on evolutionary studies.
26.
Vestigial organs are _____. ( Concept 22.3)
Your Answer:
remnants of structures that were useful to an organism's ancestors
Correct. For example, some species of snakes have remnants of pelvic and leg bones.
27.
All known organisms transcribe genetic information to protein molecules via the same genetic code. This
finding strongly supports the hypothesis that _____. ( Concept 22.3)
Your Answer: none of the above
Correct Answer:
all organisms are descended from a single common ancestor
No. One of the other choices is correct.
28.
Evidence from molecular biology supports the theory of evolution by demonstrating that _____. ( Concept 22.3)
Your Answer: none of the above
Correct Answer:
closely related organisms have more similar DNA and proteins
No. One of the other choices is correct.
29.
What did Darwin observe about species on islands? ( Concept 22.3)
Your Answer: none of the above
Correct Answer:
They are often closely related to species from the nearest mainland or neighboring islands.
No. One of the other answers is correct.
30.
To describe evolution as a "scientific theory" means that _____. ( Concept 22.3)
Your Answer:
it is a broad model that is supported by many observations and much experimental evidence
Correct. Evidence from many fields of biology makes evolution the "central, unifying principle of biology."
Your Results for "Practice Test"
Print this page
Student results on this activity were sent to the Grade Tracker. Note that it may take a few moments for the score to appear. Go to Grade Tracker.
Summary of Results for Lillian Nwanah Site Title: Campbell, Biology, 8/e AP
Book Title: Biology 8e AP* EditionBook Author: Campbell
Location on Site: 23: The Evolution of Populations > Practice TestSubmitted: March 15, 2011 at 3:51 AM (UTC/GMT)
14% Correct of 36 questions5 correct: 14%
31 incorrect: 86%
More information about scoring
1. In the context of populations, how do we define evolution? ( Overview)
Your Answer: Evolution is the tendency for some individuals in a population to leave more offspring than others
Correct Answer:
Evolution is a change in a population's allelic frequencies over generations
No. This tendency was one of Darwin's major inferences.
2. Which of the following mechanisms can alter allele frequencies? ( Overview)
Your Answer: genetic drift
Correct Answer:
all of the above
No. This is one mechanism for altering allele frequencies, but there is a better answer.
3. Which example below correctly describes average heterozygosity? ( Concept 23.1)
Your Answer: Average heterozygosity is measured by looking at changes in karyotypes.
Correct Answer:
Average heterozygosity refers to the average percentage of loci that are heterozygous in a population.
No. Average heterozygosity is concerned with the number loci with more than one allele, not with chromosome number.
4. The human genome consists of approximately 3 billion base pairs. If humans typically differ from one
another by about 3 million base pairs, what is the nucleotide variability of Homo sapiens? ( Concept 23.1)
Your Answer: 3%
Correct Answer:
0.1%
No. Check your math.
5. Which example below would most likely be a cline? ( Concept 23.1)
Your Answer: Cows are selectively bred to gain a higher milk yield.
Correct Answer:
Rabbits that live in colder regions tend to have smaller ears than rabbits of the same species that live in warmer regions.
No. This is an example of artificial selection.
6. New alleles originate from _____. ( Concept 23.1)
Your Answer: sexual recombination
Correct Answer:
mutation
No. This is not the origin of variation, but a recombination of available alleles.
7. Sexual recombination includes the shuffling of chromosomes in _____ and fertilization. ( Concept 23.1)
Your Answer: mitosis
Correct Answer:
meiosis
No. Chromosomes are duplicated but not shuffled in mitosis.
8. Which type of mutation plays the most important role in increasing the number of genes in the gene pool? (
Concept 23.2)
Your Answer: Mutations are so rare that there are no mutations that can have such an important effect.
Correct Answer:
duplication
No. This is true but it is not the best answer Mutations are the ultimate source of genetic variation.
9. In a large population of randomly breeding organisms, the frequency of a recessive allele is initially 0.3. There is no migration and no selection. Humans enter this ecosystem and selectively hunt individuals
showing the dominant trait. When the gene frequency is reexamined at the end of the year, _____. ( Concept 23.2)
Your Answer: the frequency of the homozygous dominants will go down, the frequency of the heterozygous genotype will remain the same, and the frequency of the homozygous recessives will go up
Correct Answer:
the frequency of the individuals who express the dominant phenotype will go down and the frequency of homozygous recessive individuals will go up
No. Heterozygotes express the dominant trait.
10. In the Hardy-Weinberg equation, p2 represents _____. ( Concept 23.2)
Your Answer: the total alleles in the gene pool
Correct Answer:
the expected frequency of homozygous dominant individuals in the population
No. The total number of alleles in the gene pool depends on the number of individuals in the population.
11. In a large population of bonobos, the frequency of the recessive allele is initially 0.1. There is no migration and no selection. What is the frequency of the dominant allele? Assume that there are two alleles of this gene.
( Concept 23.2)
Your Answer:
90%
Correct. p (the frequency of the dominant allele) = 1- q (the frequency of the recessive allele), or 0.9.
12. In a population in Hardy-Weinberg equilibrium, 1% of the individuals in a population show the recessive
trait of a certain characteristic. In this situation, what is the value of p? ( Concept 23.2)
Your Answer:
0.9
Correct. In this equation q2 = .01, q = 0.1, 1 - 0.1 = p
13. In the equation for Hardy-Weinberg equilibrium, 1 represents _____. ( Concept 23.2)
Your Answer: the frequency of homozygous recessive individuals in the population
Correct Answer:
the sum of the frequencies of the genotypes for a particular gene locus
No. In a situation in which there are only two alleles of a gene, q2 represents the frequency of homozygous recessive individuals.
14. Approximately 1 out of every 2,500 Caucasians in the United States is born with the recessive disease cystic fibrosis. According to the Hardy-Weinberg equilibrium equation, approximately how many people are
carriers? ( Concept 23.2)
Your Answer: about 1 in 10
Correct Answer:
about 1 in 25
No. You are not using the Hardy-Weinberg equation.
15. In a certain group of African people, 4% are born with sickle-cell disease (homozygous recessive). If this group is in Hardy-Weinberg equilibrium, what percentage of the group has the selective advantage of being more resistant to malaria (heterozygous) than those individuals who are homozygous for normal hemoglobin
or for sickle-cell disease? ( Concept 23.2)
Your Answer: 4%
Correct Answer:
32%
No. This is the frequency of homozygous recessive individuals.
16. Assume a population in Hardy-Weinberg equilibrium for a character trait with these genotypic frequencies: AA = 0.25, Aa = 0.50, and aa = 0.25. If you remove all the homozygous dominants and allow the remaining population to reproduce (again under Hardy-Weinberg conditions), what will be the frequency of
homozygous dominants in the next generation? ( Concept 23.2)
Your Answer: 0.22
Correct Answer:
0.11
No. Review the Hardy-Weinberg equation.
17. Which of the following sets of conditions is required for Hardy-Weinberg equilibrium? ( Concept 23.2)
Your Answer: no mutations, sexual selection, and no natural selection
Correct Answer:
random mating, no natural selection, and a large population
No. Hardy-Weinberg equilibrium requires random mating. A population with sexual selection would not be randomly mating.
18. _____ and _____ generate variation, while _____ results in an adaptation to the environment. (
Concept 23.2)
Your Answer:
Mutation; sexual recombination; natural selection
Correct. Mutation is the original source of variation, and sexual recombination causes new combinations of existing alleles. Natural selection results in favorable characteristics being passed on to the next generation.
19. A population of 15 birds inhabits a fairly new island. Ten of the birds are dark brown and five of them are light brown. By chance, two of the dark brown birds and three of the light brown birds die before producing any offspring. All of the birds in the next generation are dark brown. This change in phenotypic frequency
can be attributed to _____. ( Concept 23.3)
Your Answer: disruptive selection
Correct Answer:
genetic drift
No. There is no evidence that the birds' color affected their fitness.
20. An earthquake hits a small island. All but a small group of closely related lizards are eliminated, and the
survivors spread out over the island. This is an instance of _____. ( Concept 23.3)
Your Answer: mutation
Correct Answer:
bottleneck effect
No. There are no mutations described here.
21. Which of the following scenarios would most likely result in the microevolution of a population of humans?
( Concept 23.3)
Your Answer: The incidence of skin cancer in adults over age 40 rises significantly.
Correct Answer:
A colony of humans on the moon is isolated from Earth.
No. Skin cells are somatic cells and would not affect reproduction.
22. Which of the following is the best example of gene flow? ( Concept 23.3)
Your Answer: An earthquake results in the formation of a canyon, splitting a population of toads apart.
Correct Answer:
Wind blows pollen from one population of plants to another and cross-fertilization occurs.
No. Gene flow is the loss or gain of alleles from the gene pool.
23. Which of the following most accurately measures an organism's fitness? ( Concept 23.4)
Your Answer: its mutation rate
Correct Answer:
how many fertile offspring it produces
No. Most mutations are not beneficial.
24. Antibiotic resistance in bacteria is an example of which of the following? ( Concept 23.4)
Your Answer: macroevolution
Correct Answer:
directional selection
No. The spread of antibiotic resistance in a population would be an example of microevolution.
25. For several years, scientists have warned doctors of the danger of overprescribing antibiotics such as
penicillin. Scientists are concerned because _____. ( Concept 23.4)
Your Answer: the organisms that produce many of the antibiotics are overexploited and could become extinct
Correct Answer:
strains of microorganisms that are resistant to these drugs will be selected for
No. Consider the topics of this chapter.
26. A population of squirrels is preyed upon by small hawks. The smaller squirrels can escape into burrows. The larger squirrels can fight off the hawks. After several generations, the squirrels in the area tend to be very
small or very large. What process is responsible for this outcome? ( Concept 23.4)
Your Answer: directional selection
Correct Answer:
disruptive selection
No. Directional selection acts against individuals at one of the phenotypic extremes.
27. Stabilizing selection _____. ( Concept 23.4)
Your Answer:
favors intermediate variants in a population
Correct. Stabilizing selection culls extreme variants from the population.
28. Birds with average-size wings survived a severe storm more successfully than other birds in the same population with longer or shorter wings. If severe storms occur regularly, then over time, one should expect
these storms to bring about _____. ( Concept 23.4)
Your Answer: disruptive selection
Correct Answer:
stabilizing selection
No. Other wing variants are being selected against.
29. Tay-Sachs disease, which is lethal, results from having the homozygous recessive condition of the
responsible gene. Which one of the following statements is true? ( Concept 23.4)
Your Answer: In the heterozygous condition, the dominant allele will overcome the recessive allele and only the dominant allele will be passed on to offspring.
Correct Answer:
Heterozygous individuals will survive and may pass the recessive allele on to their offspring.
No. All alleles within an organism have equal chance of being passed on to offspring.
30. Which type of selection maintains stable frequencies of two or more phenotypic forms in a population? (
Concept 23.4)
Your Answer: neutral variation
Correct Answer:
balancing selection
No. This refers to genetic variations that have little or no impact on reproductive success.
31. Which of the following would seem to be an example of neutral variation? ( Concept 23.4)
Your Answer: moth coloration
Correct Answer:
human fingerprints
No. Colors usually have a purpose, such as mating or camouflage.
32. What is the importance of neutral variation in evolution? ( Concept 23.4)
Your Answer: Neutral variation is usually removed from the population by natural selection because it does not confer an advantage in the current environment.
Correct Answer:
Neutral variation increases genetic variation, allowing a population to carry more alleles that may help it respond to environmental change.
No. Natural selection does not act on neutral variation.
33. Selection that acts over evolutionary time to preserve traits that increase an individual's ability to mate is
known as _____. ( Concept 23.4)
Your Answer: directional selection
Correct Answer:
sexual selection
No. Directional selection shifts the frequency curve for some phenotypic character in one direction or the other, by favoring individuals that deviate from the average.
34. Which statement below is true about sexual selection? ( Concept 23.4)
Your Answer:
Sexual selection can result in sexual dimorphism-marked differences between the sexes in secondary sexual characteristics that are not associated directly with reproduction.
Correct. Sexual dimorphism is a result of sexual selection.
35. How does natural selection fashion organisms? ( Concept 23.4)
Your Answer: Sexual selection acts to make organisms better adapted to their environments.
Correct Answer:
Chance and the environment interact with natural selection, so that the best available traits are selected for.
No. Sexual selection often leads to compromise. Traits that increase an organism's reproductive success, such as colorful plumage in birds, may make them more susceptible to predation.
36. A number of mosquito populations today are resistant to insecticides that were once quite effective.
Biologists think that insecticide resistance evolved in mosquitoes because _____. ( Concept 23.4)
Your Answer: a new allele developed in response to the insecticide that provided future generations the benefit of resistance
Correct Answer:
a few mosquitoes were probably resistant to the insecticide before it was ever used, and these individuals were more likely to survive and reproduce
No. This is not how evolution works. New alleles do not arise on demand.
1. When gene flow between two populations ceases, the potential for _____ exists. ( Concept 24.1)
Your Answer:
(blank)
2. 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 _____. ( Concept 24.1)
Your Answer: have undergone coevolution
Correct Answer:
successfully interbreed and produce fertile offspring
No. They should never have been considered two species because they can interbreed and produce fertile offspring.
3. 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 of the following observations would, by itself, lead you to conclude unequivocally that the island
finch population had evolved into a distinct species? ( Concept 24.1)
Your Answer:
Individuals from the different populations sometimes mate with each other, but all of the resulting eggs are sterile.
Correct. The biological species concept defines a species as a population whose members interbreed successfully to produce viable, fertile offspring but who cannot produce viable, fertile offspring with members of other species.
4. Which one of the following conditions is necessary for speciation to occur? ( Concept 24.1)
Your Answer: sympatric speciation
Correct Answer:
reproductive isolation
No. This is a specific type of reproductive isolation, not a condition that leads to it.
5. At which point in the adaptation of a population is it clear that speciation has occurred? ( Concept 24.1)
Your Answer: An allopatric separation occurs.
Correct Answer:
Gene pool changes establish reproductive barriers between two populations.
No. This may lead to speciation, but it may not have occurred yet.
6. Prezygotic barriers _____. ( Concept 24.1)
Your Answer: only occur in asexual organisms
Correct Answer:
prevent fertilization of gametes from members of closely related species
No. They only occur in sexual organisms.
7. 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
_____. ( Concept 24.1)
Your Answer: postzygotic; mechanical isolation
Correct Answer:
prezygotic barrier; behavioral isolation
No. There is no evidence of morphological differences in this scenario.
8. Which of the following reproductive barriers actually prevents individuals of closely related species from
copulating successfully? ( Concept 24.1)
Your Answer: gametic isolation
Correct Answer:
mechanical isolation
No. Mating occurs, but the gametes are not compatible.
9. 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 _____. ( Concept 24.1)
Your Answer: gametic isolation
Correct Answer:
temporal isolation
No. That refers to incompatible gametes.
10. Which of the following is an example of a postzygotic reproductive barrier? ( Concept 24.1)
Your Answer: One species of flower grows in forested areas, another in meadows.
Correct Answer:
Two fruit flies of different species produce sterile offspring.
No. This is a prezygotic barrier; no mating takes place.
11. 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? ( Concept 24.1)
Your Answer: mechanical isolation
Correct Answer:
temporal isolation
No. This is due to structural differences preventing mating or pollen transfer.
12. The biological species concept emphasizes _____. ( Concept 24.1)
Your Answer: ecological niches
Correct Answer:
the evolution of reproductive isolation
No. The ecological species concept emphasizes ecological niches.
13. 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? ( Concept 24.1)
Your Answer: Study the fossil record.
Correct Answer:
Observe the fish in their natural environment for possible instances of interbreeding leading to several generations of fertile offspring.
No. There is an easier way to arrive at a conclusion.
14. In practice, how do scientists distinguish most species? ( Concept 24.1)
Your Answer: by using the paleontological species concept
Correct Answer:
by using the morphological species concept
No. This refers to morphologically discrete species that are known only from the fossil record.
15. Which species concept defines a species as a set of organisms with a unique genetic history? ( Concept 24.1)
Your Answer: biological species concept
Correct Answer:
phylogenetic species concept
No. This is the classical definition that defines a species as a population or group of populations whose members have the potential to interbreed with one another in nature and to produce viable, fertile offspring, but cannot produce viable, fertile offspring with members of other populations.
16. 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 _____. (
Concept 24.1)
Your Answer:
may indicate that the formation of a new species is in progress
Correct. This could indicate that although a reproductive barrier is becoming established, it is not yet complete.
17. Which of the following organisms are most likely to be subject to allopatric speciation? ( Concept 24.2)
Your Answer: mountain lions in the canyons of Wyoming and in the canyons of Utah
Correct Answer:
pine trees in Alaska and pine trees on the island of Madagascar
No. These represent one population because mountain lions recognize neither political barriers nor most topographical barriers.
18. According to the experiment of Diane Dodd, can adaptive divergence of allopatric fruit fly populations lead
to reproductive isolation? ( Concept 24.2)
Your Answer: After several generations, the reproductive barrier (behavioral isolation) between the starch- and maltose-fed populations was complete.
Correct Answer:
After several generations, the formation of a reproductive barrier (behavioral isolation) was evident, but not absolute.
No. Some mating between the starch flies and maltose flies did occur.
19. In which of the following groups has sympatric speciation been most important? ( Concept 24.2)
Your Answer: animals
Correct Answer:
plants
No. Sympatric speciation does not seem to have been an important factor in animal speciation.
20. 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? ( Concept 24.2)
Your Answer: none of the above
Correct 12
Answer:
No. One of the other choices is correct.
No. The two gametes would be n = 2 and n = 4. They would combine for a total of 6, which after doubling would be 12.
21. A new species can arise in a single generation _____. ( Concept 24.2)
Your Answer: if allopatric speciation occurs
Correct Answer:
if a change in chromosome number creates a reproductive barrier
No. Allopatric speciation occurs by geographic isolation, and it takes several generations for speciation to occur in this manner.
22. 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
_____. ( Concept 24.2)
Your Answer:
allopatric speciation
Correct. As the finches spread out to different islands and became isolated from each other, gene flow between them ceased, and new species arose.
23. In the case of the Lake Victoria cichlids, sympatric speciation has been shown to be driven by ______. (
Concept 24.2)
Your Answer: habitat differentiation
Correct Answer:
sexual selection
No. Although habitat differentiation has been suggested as a possible mechanism for sympatric speciation in the lake, sexual selection has been shown to be a factor.
24. In a hybrid zone which of the following would tend to lead to reinforcement? ( Concept 24.3)
Your Answer:
all of the above
Correct. All of these factors can reinforce the reproductive barriers between populations.
25. In the Lake Victoria cichlids, what appears to be contributing to fusion of different species? ( Concept 24.3)
Your Answer: Extinctions are being caused by the Nile perch, an introduced predator.
Correct Answer:
Murky, polluted water is making it difficult for females to visually select for males of the same species.
No. Although the introduction of the Nile perch has led to the extinction of some cichlid species, it does not appear to be contributing to the observed fusion.
26. According to the punctuated equilibrium model of evolution _____. ( Concept 24.4)
Your Answer: none of the above
Correct Answer:
the tempo of evolution consists of abrupt episodes of speciation among long periods of equilibrium
No. One of the other choices is correct.
27. 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? ( Concept 24.4)
Your Answer: It is about time for humans to undergo a burst of change.
Correct Answer:
Lack of change is consistent with the punctuated equilibrium model.
No. In punctuated equilibrium, new species change little after budding from their parent species.
28. What is the first thing that must happen in order for speciation to occur? ( Concept 24.4)
Your Answer:
Gene flow between populations must be interrupted.
Correct. Although several other factors come into play, as long as there is gene flow between populations, speciation is extremely unlikely.
29. How many genes must change in order to form a new species? ( Concept 24.4)
Your Answer: 14
Correct Answer:
There is no set number of genes or loci that produces a new species. Genetic and environmental factors interact.
No. Undoubtedly a speciation event has occurred based on changes in 14 genes, but there is a better answer.
30. The time interval between speciation events is typically _____ ( Concept 24.4)
Your Answer:
Times between speciation events vary widely and depend on generation times, causes of speciation, environmental factors, and chance.
Correct. Speciation may occur on many different time scales. Remember that mutations or meiosis, both of which are largely governed by chance, must first provide some traits that can lead to reproductive
1. Why is the four-stage hypothesis for the abiotic origin of life useful? ( Concept 25.1)
Your Answer: It proves that RNA was the first genetic molecule.
Correct Answer:
It leads to predictions that can be tested.
No. While there is some interesting evidence to support that assertion, the hypothesis is not proof.
2. The early atmosphere on Earth is thought to have lacked which one of the following gases? ( Concept 25.1)
Your Answer: nitrogen
Correct Answer:
oxygen
No. Nitrogen is likely to have been abundant in the primitive atmosphere.
3. Currently scientists think the early atmosphere probably consisted of _____. ( Concept 25.1)
Your Answer:
N2, H2O, CO2, NH3, CH4, H2, and H2S
Correct. These are the gases currently thought to have made up the early atmosphere, which may not have been either reducing or oxidizing.
4. The Miller and Urey abiotic synthesis experiment (and subsequent, similar experiments) showed that _____.
( Concept 25.1)
Your Answer: the earliest life forms introduced large amounts of oxygen into the atmosphere
Correct Answer:
simple organic molecules can form spontaneously under conditions like those thought to prevail early in Earth's history
No. The primitive atmosphere did not contain large amounts of O2.
5. The early atmosphere may not have been as reducing as originally postulated by Haldane, Oparin, Miller, and Urey. In light of current thinking about the composition of the early atmosphere, what is regarded as a likely
place for the abiotic synthesis of organic molecules to have occurred? ( Concept 25.1)
Your Answer: banded iron formations
Correct Answer:
deep sea hydrothermal vents
No. Banded iron formations show evidence of strong oxidation. A strongly oxidizing environment would not have favored the abiotic synthesis of organic molecules.
6. Protobionts, such as liposomes, display which of the following rudimentary qualities necessary for life? (
Concept 25.1)
Your Answer:
the ability to perform simple reproduction and metabolism
Correct. Protobionts are capable of dividing and performing simple metabolic reactions.
7. Cech and Altman suggested that the first self-replicating molecules were _____. ( Concept 25.1)
Your Answer: true proteins
Correct Answer:
RNA
No. Proteins are not self-replicating.
8. A radioactive isotope has a half-life of 1.2 billion years. As measured by the presence of the isotope and its stable decay product, a rock originally contained 10 grams of the radioactive isotope, and now contains 1.25
grams. Approximately how many years old is the rock? ( Concept 25.2)
Your Answer: 0.3 billion years
Correct Answer:
3.6 billion years
No. Three half-lives have elapsed since the sample was alive (10 grams to 5 grams, 5 grams to 2.5 grams, and 2.5 grams to 1.25 grams). Because half the isotope would be expected to decay by the end of each half-life, the sample is 3 x 1.2 billion years old.
9. Fossils that can be used to establish relative dates are most likely to be found in _____. ( Concept 25.2)
Your Answer: glacial till (i.e., rubble)
Correct Answer:
sedimentary rock
No. Glacial rubble may contain fossils, but is jumbled and no longer presents a usable sequence from deepest (oldest) to most shallow (youngest).
10. You are watching a movie in which one of the characters excitedly claims to have found human remains
dated at 10 million years old. The date was obtained by carbon-14 dating. What is your reaction? ( Concept 25.2)
Your Answer: This would be a surprising finding because so far there is no evidence that humans existed that long ago.
Correct Answer:
This can't possibly be true because carbon-14 dating can only be used back to about 75,000 years.
No. It would be a surprising finding if it could be taken seriously. Remember that carbon-14 dating is only accurate to around 75,000 years ago, so claims of carbon-14 dates in the 10-million-year range are clearly bogus.
11. Single-celled prokaryotes had the Earth to themselves for approximately _____. ( Concept 25.3)
Your Answer: 1.5 million years
Correct Answer:
1.5 billion years
No. Prokaryotes, which are all single-celled, were the only organisms on earth from sometime before 3.5 billion years ago until around 2 billion years ago. That's about 1.5 billion years.
12. The correct order of the geologic eras, from most ancient to most recent, is _____. ( Concept 25.3)
Your Answer: Paleozoic, Cenozoic, Mesozoic
Correct Answer:
Paleozoic, Mesozoic, Cenozoic
No. The Cenozoic is the current era.
13. Ancient cyanobacteria were very important in the history of life because they _____. ( Concept 25.3)
Your Answer: were the first truly multicellular organisms
Correct Answer:
produced atmospheric oxygen
No. They were not truly multicellular.
14. What prokaryotic adaptation occurred during the oxygen revolution and opened up the possibility for energy-
No. Forms of photosynthesis existed before the oxygen revolution. In fact, the actions of photosynthetic prokaryotes were the cause of the oxygen revolution.
15. What evidence supports the hypothesis that mitochondria and plastids evolved from prokaryotic
endosymbionts? ( Concept 25.3)
Your Answer: Their ribosomes are more like prokaryotic ribosomes than eukaryotic ribosomes.
Correct Answer:
both a and c
No. This statement is true, but there is a better answer.
16. Prior to the Cambrian explosion, most animals were small and soft-bodied. What development appears to
have spurred adaptations such as sharp spines, claws, and body armor (shells)? ( Concept 25.3)
Your Answer: aerobic respiration
Correct Answer:
predation
No. Aerobic respiration may have made it possible for animals to grow bigger, but it did not directly select for spines, claws, and body armor.
17. What were the two major "problems" that had to be solved before plants, animals, and fungi could move into
terrestrial habitats? ( Concept 25.3)
Your Answer:
reproduction and prevention of dehydration
Correct. Life originally evolved in water and depends on aqueous solutions for many processes. Gametes generally have to swim to each other for fertilization. Until adaptations to address these two issues evolved, vast amounts of terrestrial habitat were unusable.
18. What does the snowball Earth hypothesis propose? ( Concept 25.3)
Your Answer: Once the first multicellular eukaryotes appeared, their sizes and populations grew exponentially, like a snowball rolling down a hill.
Correct Answer:
Larger multicellular eukaryotes are scarce in the fossil record until the late Proterozoic because an ice age limited life to deep-sea vents and hot springs.
No. Some believe that the evolution of multicellular eukaryotes was limited by a 180-million-year-long ice age.
19. Plants colonized land in the company of _____; their symbiotic relationships still exist today. ( Concept 25.3)
Your Answer: animals
Correct Answer:
fungi
No. The question is referring to fungi. Even today, the roots of most plants are associated with fungi that aid in the absorption of water and minerals from the soil.
20. What evidence most strongly suggests that an impact by an asteroid or meteorite may have caused the
extinction of the dinosaurs? ( Concept 25.4)
Your Answer: There have been several near misses in recent years.
Correct Answer:
Sedimentary rocks contain a layer of iridium, a mineral uncommon on Earth.
No. A layer of iridium, probably from the collision of an asteroid with Earth, is found at the Mesozoic-Cenozoic boundary. Iridium is uncommon on Earth.
21. Which one of the following best describes how the breakup of Pangaea affected evolution? ( Concept 25.4)
Your Answer: Mammals had an opportunity to become dominant.
Correct Answer:
The geographic isolation of populations that had previously coexisted led to speciation.
No. Pangaea broke up during the Mesozoic era—the age of reptiles. Mammalian dominance came later.
22. The fauna and flora of Australia are very different from those of the rest of the world. Why might this be
true? ( Concept 25.4)
Your Answer:
Australia has been isolated for about 50 million years.
Correct. Such a long period of isolation has allowed for the evolution of unique forms of life.
23. Lake Malawi, in the African Rift Valley, is home to more than a hundred species of cichlid fishes, each with slightly different diets and habits. All these species probably evolved from a common ancestor, making them
an example of _____. ( Concept 25.4)
Your Answer: convergence
Correct Answer:
adaptive radiation
No. Convergence occurs when unrelated organisms come to resemble each other by adapting under the same
selective pressures. What has occurred among the cichlids of Lake Malawai is, rather, divergence.
24. Adaptive radiations are often seen after ______. ( Concept 25.4)
Your Answer: mass extinctions
Correct Answer:
both b and c
No. Adaptive radiations do usually occur after mass extinctions, but there is a better answer.
25. Although they originated around 180 million years ago, mammals underwent an adaptive radiation starting
approximately 65 million years ago. Why? ( Concept 25.4)
Your Answer: Mammals were mostly nocturnal until 65 million years ago.
Correct Answer:
Between 180 and 65 million years ago, mammals were out-competed by the well-established dinosaurs.
No. Many mammals that existed before 65 million years ago do appear to have been nocturnal, but that is not sufficient to explain their relative unimportance.
26. How does continental drift affect speciation? ( Concept 25.4)
Your Answer:
all of the above
Correct. These are all ways in which continental drift can affect speciation.
27. Mutations in what class of genes have probably been responsible for many of the changes leading to the great
diversity of life existing today? ( Concept 25.5)
Your Answer:
developmental genes
Correct. Small changes in developmental genes such as Hox genes can produce large morphologic changes.
28. The products of Hox genes _____. ( Concept 25.5)
Your Answer: can cause paedomorphosis
Correct Answer:
provide positional information in animal embryos
No. The products of these genes prompt cells in animal embryos to develop into structures appropriate for a particular location.
29. If the wings of extant flying birds originally arose as thermoregulatory devices in ancestral reptiles, then the
bird wings could be accurately described as _____. ( Concept 25.6)
Your Answer: degenerate structures
Correct Answer:
exaptations
No. In fact, wings are very complicated structures and not at all degenerate.
30. In the species selection model, _______ is to macroevolution what _______ is to microevolution. ( Concept 25.6)
No. Exaptation and adaptation both refer to the generation of novel attributes that increase an organism's fitness.
1. Why is the four-stage hypothesis for the abiotic origin of life useful? ( Concept 25.1)
Your Answer: It proves that RNA was the first genetic molecule.
Correct Answer:
It leads to predictions that can be tested.
No. While there is some interesting evidence to support that assertion, the hypothesis is not proof.
2. The early atmosphere on Earth is thought to have lacked which one of the following gases? ( Concept 25.1)
Your Answer: nitrogen
Correct Answer:
oxygen
No. Nitrogen is likely to have been abundant in the primitive atmosphere.
3. Currently scientists think the early atmosphere probably consisted of _____. ( Concept 25.1)
Your Answer:
N2, H2O, CO2, NH3, CH4, H2, and H2S
Correct. These are the gases currently thought to have made up the early atmosphere, which may not have been either reducing or oxidizing.
4. The Miller and Urey abiotic synthesis experiment (and subsequent, similar experiments) showed that _____.
( Concept 25.1)
Your Answer: the earliest life forms introduced large amounts of oxygen into the atmosphere
Correct Answer:
simple organic molecules can form spontaneously under conditions like those thought to prevail early in Earth's history
No. The primitive atmosphere did not contain large amounts of O2.
5. The early atmosphere may not have been as reducing as originally postulated by Haldane, Oparin, Miller, and Urey. In light of current thinking about the composition of the early atmosphere, what is regarded as a likely
place for the abiotic synthesis of organic molecules to have occurred? ( Concept 25.1)
Your Answer: banded iron formations
Correct Answer:
deep sea hydrothermal vents
No. Banded iron formations show evidence of strong oxidation. A strongly oxidizing environment would not have favored the abiotic synthesis of organic molecules.
6. Protobionts, such as liposomes, display which of the following rudimentary qualities necessary for life? (
Concept 25.1)
Your Answer:
the ability to perform simple reproduction and metabolism
Correct. Protobionts are capable of dividing and performing simple metabolic reactions.
7. Cech and Altman suggested that the first self-replicating molecules were _____. ( Concept 25.1)
Your Answer: true proteins
Correct Answer:
RNA
No. Proteins are not self-replicating.
8. A radioactive isotope has a half-life of 1.2 billion years. As measured by the presence of the isotope and its stable decay product, a rock originally contained 10 grams of the radioactive isotope, and now contains 1.25
grams. Approximately how many years old is the rock? ( Concept 25.2)
Your Answer: 0.3 billion years
Correct Answer:
3.6 billion years
No. Three half-lives have elapsed since the sample was alive (10 grams to 5 grams, 5 grams to 2.5 grams, and 2.5 grams to 1.25 grams). Because half the isotope would be expected to decay by the end of each half-
life, the sample is 3 x 1.2 billion years old.
9. Fossils that can be used to establish relative dates are most likely to be found in _____. ( Concept 25.2)
Your Answer: glacial till (i.e., rubble)
Correct Answer:
sedimentary rock
No. Glacial rubble may contain fossils, but is jumbled and no longer presents a usable sequence from deepest (oldest) to most shallow (youngest).
10. You are watching a movie in which one of the characters excitedly claims to have found human remains
dated at 10 million years old. The date was obtained by carbon-14 dating. What is your reaction? ( Concept 25.2)
Your Answer: This would be a surprising finding because so far there is no evidence that humans existed that long ago.
Correct Answer:
This can't possibly be true because carbon-14 dating can only be used back to about 75,000 years.
No. It would be a surprising finding if it could be taken seriously. Remember that carbon-14 dating is only accurate to around 75,000 years ago, so claims of carbon-14 dates in the 10-million-year range are clearly bogus.
11. Single-celled prokaryotes had the Earth to themselves for approximately _____. ( Concept 25.3)
Your Answer: 1.5 million years
Correct Answer:
1.5 billion years
No. Prokaryotes, which are all single-celled, were the only organisms on earth from sometime before 3.5 billion years ago until around 2 billion years ago. That's about 1.5 billion years.
12. The correct order of the geologic eras, from most ancient to most recent, is _____. ( Concept 25.3)
Your Answer: Paleozoic, Cenozoic, Mesozoic
Correct Answer:
Paleozoic, Mesozoic, Cenozoic
No. The Cenozoic is the current era.
13. Ancient cyanobacteria were very important in the history of life because they _____. ( Concept 25.3)
Your Answer: were the first truly multicellular organisms
Correct Answer:
produced atmospheric oxygen
No. They were not truly multicellular.
14. What prokaryotic adaptation occurred during the oxygen revolution and opened up the possibility for energy-
No. Forms of photosynthesis existed before the oxygen revolution. In fact, the actions of photosynthetic prokaryotes were the cause of the oxygen revolution.
15. What evidence supports the hypothesis that mitochondria and plastids evolved from prokaryotic
endosymbionts? ( Concept 25.3)
Your Answer: Their ribosomes are more like prokaryotic ribosomes than eukaryotic ribosomes.
Correct Answer:
both a and c
No. This statement is true, but there is a better answer.
16. Prior to the Cambrian explosion, most animals were small and soft-bodied. What development appears to
have spurred adaptations such as sharp spines, claws, and body armor (shells)? ( Concept 25.3)
Your Answer: aerobic respiration
Correct Answer:
predation
No. Aerobic respiration may have made it possible for animals to grow bigger, but it did not directly select for spines, claws, and body armor.
17. What were the two major "problems" that had to be solved before plants, animals, and fungi could move into
terrestrial habitats? ( Concept 25.3)
Your Answer:
reproduction and prevention of dehydration
Correct. Life originally evolved in water and depends on aqueous solutions for many processes. Gametes generally have to swim to each other for fertilization. Until adaptations to address these two issues evolved, vast amounts of terrestrial habitat were unusable.
18. What does the snowball Earth hypothesis propose? ( Concept 25.3)
Your Answer: Once the first multicellular eukaryotes appeared, their sizes and populations grew exponentially, like a snowball rolling down a hill.
Correct Answer:
Larger multicellular eukaryotes are scarce in the fossil record until the late Proterozoic because an ice age limited life to deep-sea vents and hot springs.
No. Some believe that the evolution of multicellular eukaryotes was limited by a 180-million-year-long ice age.
19. Plants colonized land in the company of _____; their symbiotic relationships still exist today. ( Concept 25.3)
Your Answer: animals
Correct Answer:
fungi
No. The question is referring to fungi. Even today, the roots of most plants are associated with fungi that aid in the absorption of water and minerals from the soil.
20. What evidence most strongly suggests that an impact by an asteroid or meteorite may have caused the
extinction of the dinosaurs? ( Concept 25.4)
Your Answer: There have been several near misses in recent years.
Correct Answer:
Sedimentary rocks contain a layer of iridium, a mineral uncommon on Earth.
No. A layer of iridium, probably from the collision of an asteroid with Earth, is found at the Mesozoic-Cenozoic boundary. Iridium is uncommon on Earth.
21. Which one of the following best describes how the breakup of Pangaea affected evolution? ( Concept 25.4)
Your Answer: Mammals had an opportunity to become dominant.
Correct Answer:
The geographic isolation of populations that had previously coexisted led to speciation.
No. Pangaea broke up during the Mesozoic era—the age of reptiles. Mammalian dominance came later.
22. The fauna and flora of Australia are very different from those of the rest of the world. Why might this be
true? ( Concept 25.4)
Your Answer:
Australia has been isolated for about 50 million years.
Correct. Such a long period of isolation has allowed for the evolution of unique forms of life.
23. Lake Malawi, in the African Rift Valley, is home to more than a hundred species of cichlid fishes, each with slightly different diets and habits. All these species probably evolved from a common ancestor, making them
an example of _____. ( Concept 25.4)
Your Answer: convergence
Correct Answer:
adaptive radiation
No. Convergence occurs when unrelated organisms come to resemble each other by adapting under the same selective pressures. What has occurred among the cichlids of Lake Malawai is, rather, divergence.
24. Adaptive radiations are often seen after ______. ( Concept 25.4)
Your Answer: mass extinctions
Correct Answer:
both b and c
No. Adaptive radiations do usually occur after mass extinctions, but there is a better answer.
25. Although they originated around 180 million years ago, mammals underwent an adaptive radiation starting
approximately 65 million years ago. Why? ( Concept 25.4)
Your Answer: Mammals were mostly nocturnal until 65 million years ago.
Correct Answer:
Between 180 and 65 million years ago, mammals were out-competed by the well-established dinosaurs.
No. Many mammals that existed before 65 million years ago do appear to have been nocturnal, but that is not sufficient to explain their relative unimportance.
26. How does continental drift affect speciation? ( Concept 25.4)
Your Answer:
all of the above
Correct. These are all ways in which continental drift can affect speciation.
27. Mutations in what class of genes have probably been responsible for many of the changes leading to the great
diversity of life existing today? ( Concept 25.5)
Your Answer:
developmental genes
Correct. Small changes in developmental genes such as Hox genes can produce large morphologic changes.
28. The products of Hox genes _____. ( Concept 25.5)
Your Answer: can cause paedomorphosis
Correct Answer:
provide positional information in animal embryos
No. The products of these genes prompt cells in animal embryos to develop into structures appropriate for a particular location.
29. If the wings of extant flying birds originally arose as thermoregulatory devices in ancestral reptiles, then the
bird wings could be accurately described as _____. ( Concept 25.6)
Your Answer: degenerate structures
Correct Answer:
exaptations
No. In fact, wings are very complicated structures and not at all degenerate.
30. In the species selection model, _______ is to macroevolution what _______ is to microevolution. ( Concept 25.6)
No. Exaptation and adaptation both refer to the generation of novel attributes that increase an organism's fitness.
1. Why is the four-stage hypothesis for the abiotic origin of life useful? ( Concept 25.1)
Your Answer: It proves that RNA was the first genetic molecule.
Correct Answer:
It leads to predictions that can be tested.
No. While there is some interesting evidence to support that assertion, the hypothesis is not proof.
2. The early atmosphere on Earth is thought to have lacked which one of the following gases? ( Concept 25.1)
Your Answer: nitrogen
Correct Answer:
oxygen
No. Nitrogen is likely to have been abundant in the primitive atmosphere.
3. Currently scientists think the early atmosphere probably consisted of _____. ( Concept 25.1)
Your Answer:
N2, H2O, CO2, NH3, CH4, H2, and H2S
Correct. These are the gases currently thought to have made up the early atmosphere, which may not have been either reducing or oxidizing.
4. The Miller and Urey abiotic synthesis experiment (and subsequent, similar experiments) showed that _____.
( Concept 25.1)
Your Answer: the earliest life forms introduced large amounts of oxygen into the atmosphere
Correct Answer:
simple organic molecules can form spontaneously under conditions like those thought to prevail early in Earth's history
No. The primitive atmosphere did not contain large amounts of O2.
5. The early atmosphere may not have been as reducing as originally postulated by Haldane, Oparin, Miller, and Urey. In light of current thinking about the composition of the early atmosphere, what is regarded as a likely
place for the abiotic synthesis of organic molecules to have occurred? ( Concept 25.1)
Your Answer: banded iron formations
Correct Answer:
deep sea hydrothermal vents
No. Banded iron formations show evidence of strong oxidation. A strongly oxidizing environment would not have favored the abiotic synthesis of organic molecules.
6. Protobionts, such as liposomes, display which of the following rudimentary qualities necessary for life? (
Concept 25.1)
Your Answer:
the ability to perform simple reproduction and metabolism
Correct. Protobionts are capable of dividing and performing simple metabolic reactions.
7. Cech and Altman suggested that the first self-replicating molecules were _____. ( Concept 25.1)
Your Answer: true proteins
Correct Answer:
RNA
No. Proteins are not self-replicating.
8. A radioactive isotope has a half-life of 1.2 billion years. As measured by the presence of the isotope and its stable decay product, a rock originally contained 10 grams of the radioactive isotope, and now contains 1.25
grams. Approximately how many years old is the rock? ( Concept 25.2)
Your Answer: 0.3 billion years
Correct Answer:
3.6 billion years
No. Three half-lives have elapsed since the sample was alive (10 grams to 5 grams, 5 grams to 2.5 grams, and 2.5 grams to 1.25 grams). Because half the isotope would be expected to decay by the end of each half-life, the sample is 3 x 1.2 billion years old.
9. Fossils that can be used to establish relative dates are most likely to be found in _____. ( Concept 25.2)
Your Answer: glacial till (i.e., rubble)
Correct Answer:
sedimentary rock
No. Glacial rubble may contain fossils, but is jumbled and no longer presents a usable sequence from deepest (oldest) to most shallow (youngest).
10. You are watching a movie in which one of the characters excitedly claims to have found human remains
dated at 10 million years old. The date was obtained by carbon-14 dating. What is your reaction? ( Concept 25.2)
Your Answer: This would be a surprising finding because so far there is no evidence that humans existed that long ago.
Correct Answer:
This can't possibly be true because carbon-14 dating can only be used back to about 75,000 years.
No. It would be a surprising finding if it could be taken seriously. Remember that carbon-14 dating is only accurate to around 75,000 years ago, so claims of carbon-14 dates in the 10-million-year range are clearly bogus.
11. Single-celled prokaryotes had the Earth to themselves for approximately _____. ( Concept 25.3)
Your Answer: 1.5 million years
Correct Answer:
1.5 billion years
No. Prokaryotes, which are all single-celled, were the only organisms on earth from sometime before 3.5 billion years ago until around 2 billion years ago. That's about 1.5 billion years.
12. The correct order of the geologic eras, from most ancient to most recent, is _____. ( Concept 25.3)
Your Answer: Paleozoic, Cenozoic, Mesozoic
Correct Answer:
Paleozoic, Mesozoic, Cenozoic
No. The Cenozoic is the current era.
13. Ancient cyanobacteria were very important in the history of life because they _____. ( Concept 25.3)
Your Answer: were the first truly multicellular organisms
Correct Answer:
produced atmospheric oxygen
No. They were not truly multicellular.
14. What prokaryotic adaptation occurred during the oxygen revolution and opened up the possibility for energy-
No. Forms of photosynthesis existed before the oxygen revolution. In fact, the actions of photosynthetic prokaryotes were the cause of the oxygen revolution.
15. What evidence supports the hypothesis that mitochondria and plastids evolved from prokaryotic
endosymbionts? ( Concept 25.3)
Your Answer: Their ribosomes are more like prokaryotic ribosomes than eukaryotic ribosomes.
Correct Answer:
both a and c
No. This statement is true, but there is a better answer.
16. Prior to the Cambrian explosion, most animals were small and soft-bodied. What development appears to
have spurred adaptations such as sharp spines, claws, and body armor (shells)? ( Concept 25.3)
Your Answer: aerobic respiration
Correct Answer:
predation
No. Aerobic respiration may have made it possible for animals to grow bigger, but it did not directly select for spines, claws, and body armor.
17. What were the two major "problems" that had to be solved before plants, animals, and fungi could move into
terrestrial habitats? ( Concept 25.3)
Your Answer:
reproduction and prevention of dehydration
Correct. Life originally evolved in water and depends on aqueous solutions for many processes. Gametes generally have to swim to each other for fertilization. Until adaptations to address these two issues evolved, vast amounts of terrestrial habitat were unusable.
18. What does the snowball Earth hypothesis propose? ( Concept 25.3)
Your Answer: Once the first multicellular eukaryotes appeared, their sizes and populations grew exponentially, like a snowball rolling down a hill.
Correct Answer:
Larger multicellular eukaryotes are scarce in the fossil record until the late Proterozoic because an ice age limited life to deep-sea vents and hot springs.
No. Some believe that the evolution of multicellular eukaryotes was limited by a 180-million-year-long ice age.
19. Plants colonized land in the company of _____; their symbiotic relationships still exist today. ( Concept 25.3)
Your Answer: animals
Correct Answer:
fungi
No. The question is referring to fungi. Even today, the roots of most plants are associated with fungi that aid in the absorption of water and minerals from the soil.
20. What evidence most strongly suggests that an impact by an asteroid or meteorite may have caused the
extinction of the dinosaurs? ( Concept 25.4)
Your Answer: There have been several near misses in recent years.
Correct Answer:
Sedimentary rocks contain a layer of iridium, a mineral uncommon on Earth.
No. A layer of iridium, probably from the collision of an asteroid with Earth, is found at the Mesozoic-Cenozoic boundary. Iridium is uncommon on Earth.
21. Which one of the following best describes how the breakup of Pangaea affected evolution? ( Concept 25.4)
Your Answer: Mammals had an opportunity to become dominant.
Correct Answer:
The geographic isolation of populations that had previously coexisted led to speciation.
No. Pangaea broke up during the Mesozoic era—the age of reptiles. Mammalian dominance came later.
22. The fauna and flora of Australia are very different from those of the rest of the world. Why might this be
true? ( Concept 25.4)
Your Answer:
Australia has been isolated for about 50 million years.
Correct. Such a long period of isolation has allowed for the evolution of unique forms of life.
23. Lake Malawi, in the African Rift Valley, is home to more than a hundred species of cichlid fishes, each with slightly different diets and habits. All these species probably evolved from a common ancestor, making them
an example of _____. ( Concept 25.4)
Your Answer: convergence
Correct Answer:
adaptive radiation
No. Convergence occurs when unrelated organisms come to resemble each other by adapting under the same selective pressures. What has occurred among the cichlids of Lake Malawai is, rather, divergence.
24. Adaptive radiations are often seen after ______. ( Concept 25.4)
Your Answer: mass extinctions
Correct Answer:
both b and c
No. Adaptive radiations do usually occur after mass extinctions, but there is a better answer.
25. Although they originated around 180 million years ago, mammals underwent an adaptive radiation starting
approximately 65 million years ago. Why? ( Concept 25.4)
Your Answer: Mammals were mostly nocturnal until 65 million years ago.
Correct Answer:
Between 180 and 65 million years ago, mammals were out-competed by the well-established dinosaurs.
No. Many mammals that existed before 65 million years ago do appear to have been nocturnal, but that is not sufficient to explain their relative unimportance.
26. How does continental drift affect speciation? ( Concept 25.4)
Your Answer:
all of the above
Correct. These are all ways in which continental drift can affect speciation.
27. Mutations in what class of genes have probably been responsible for many of the changes leading to the great
diversity of life existing today? ( Concept 25.5)
Your Answer:
developmental genes
Correct. Small changes in developmental genes such as Hox genes can produce large morphologic changes.
28. The products of Hox genes _____. ( Concept 25.5)
Your Answer: can cause paedomorphosis
Correct Answer:
provide positional information in animal embryos
No. The products of these genes prompt cells in animal embryos to develop into structures appropriate for a particular location.
29. If the wings of extant flying birds originally arose as thermoregulatory devices in ancestral reptiles, then the
bird wings could be accurately described as _____. ( Concept 25.6)
Your Answer: degenerate structures
Correct Answer:
exaptations
No. In fact, wings are very complicated structures and not at all degenerate.
30. In the species selection model, _______ is to macroevolution what _______ is to microevolution. ( Concept 25.6)
No. Exaptation and adaptation both refer to the generation of novel attributes that increase an organism's fitness.
1. The analytical approach to understanding the diversity and relatedness of both extant and extinct
organisms is called _____. ( Overview)
Your Answer:
(blank)
2. What is the focus of the branch of biology called taxonomy? ( Concept 26.1)
Your Answer: the environment
Correct Answer:
the classification of life-forms by their similarities and differences
No. The study of environmental biology is referred to as ecology.
3. The binomial system assigns to each organism a unique name that describes its _____. ( Concept 26.1)
Your Answer:
genus and species
Correct. Each species is assigned a two-part Latin name, or binomial. The first word is the genus and the second word is the species. Species that are very similar are grouped into the same genus.
4. The two-part format of the scientific name, referred to as binomial, ensures that _____. ( Concept 26.1)
Your Answer: systematists can easily specify the closest relatives of any species
Correct Answer:
all of the above
No. This is true, but there is a better response.
5. All the members of which one of the following groups have the greatest number of characteristics in
common? ( Concept 26.1)
Your Answer: genus
Correct Answer:
species
No. Of the choices, this is not the least inclusive level of classification.
6. A taxon _____. ( Concept 26.1)
Your Answer: is a species
Correct Answer:
is a formal grouping at any given level
No. A taxon is a formal grouping at any given level.
7. Two worms in the same class must also be grouped in the same _____. ( Concept 26.1)
Your Answer: genus
Correct Answer:
phylum
No. Genus is less inclusive than class; thus, they could be in the same class and different genera.
8. Species A and species B are in the same phylum. Species A and species C, but not species B, are in the same
order. From this information you can conclude that _____. ( Concept 26.1)
Your Answer:
species C could be in the same class as species A and B
Correct. If species A and species C are in the same order, then they must also be in the same class. Since you know that species A and species B are in the same phylum, it is possible that they are in the same class, but different orders.
9. What does a branch point in a phylogenetic tree represent? ( Concept 26.1)
Your Answer: A branch point represents the absolute time at which two evolutionary lineages split from a common ancestor.
Correct Answer:
A branch point represents a point at which two evolutionary lineages split from a common ancestor.
No. Without evidence from the fossil record and radiometric dating, it is not possible to put an absolute date on branch points.
10. Which one of the following methods to establish phylogenetic relationships among organisms has been
developed most recently? ( Concept 26.2)
Your Answer: comparing behavioral patterns
Correct Answer:
comparing the component sequences of proteins and nucleic acids
No. This is a method of observation and could be performed to some extent without the technology we have available today.
11. The wings of a hummingbird and a bee are _____. ( Concept 26.2)
Your Answer: binomial
Correct Answer:
analogous
No. An organism's scientific name is a binomial consisting of the genus and the specific epithet.
12. Which of the following would be the least useful in determining the relationships among various species? (
Concept 26.2)
Your Answer: fossils
Correct Answer:
analogous structures
No. Ancestral-descendant sequences can be traced through the fossil record.
13. Researchers can use molecular homologies to _____. ( Concept 26.2)
Your Answer: all of the above
Correct Answer:
reveal the amount of mutations in a particular sequence that have occurred between the species since they diverged from a common ancestor
No. Only one of the other choices is correct.
14. A phylogenetic tree of bird families constructed by cladistic analysis would be a hypothesis about which of
the following? ( Concept 26.3)
Your Answer: families that look most alike
Correct Answer:
evolutionary relationships among bird families
No. Phylogeny does not necessarily match similarity of appearance.
15. Looking at the table and phylogenetic tree in Figure 26.11, which of the following is a true statement? (
Concept 26.3)
Your Answer: Four walking legs is a shared derived character in leopards.
Correct Answer:
Four walking legs is a shared derived character in salamanders and a shared ancestral character in turtles.
No. Since four legs appear in salamanders and turtles, they constitute a shared ancestral character.
16. Many researchers who study the kingdom Protista argue that all of these organisms should not be placed in the same kingdom, because these organisms could not have evolved from a common ancestor. In other
words, they argue that the kingdom Protista is _____. ( Concept 26.3)
Your Answer: monophyletic
Correct Answer:
polyphyletic
No. The members of a monophyletic clade share a common ancestor. However, unlike a paraphyletic group, all of the individuals derived from the most recent common ancestor are included.
17. Using cladistic analysis, a taxonomist wishes to construct a phylogenetic tree showing the relationships among various species of mammals. Which of the following would be the least useful for this purpose? (
Concept 26.3)
Your Answer: the fact that teeth vary among types of mammals
Correct Answer:
the fact that all mammals have hair
No. Variation among the teeth of different types of mammals may be used to distinguish among shared primitive and shared derived characteristics.
18. Which statement below is true about an outgroup? ( Concept 26.3)
Your Answer: none of the above
Correct Answer:
The outgroup should be less closely related to any members of the ingroup than they are to each other.
No. One of the statements is true.
19. Phylogenetic trees with branch lengths proportional to time can be used to _____. ( Concept 26.3)
Your Answer: reflect the number of evolutionary changes that have taken place in a lineage
Correct Answer:
represent the chronological time that has passed since two groups diverged from a common ancestor
No. This is true of regular phylogenetic trees.
20. Which statement below is true of parsimonious trees? ( Concept 26.3)
Your Answer: Given the rules of how morphological traits change over time, a tree can be found that reflects the most likely sequence of evolutionary events.
Correct Answer:
The best tree requires the fewest evolutionary events to have occurred in the form of shared derived characters.
No. There are no true rules about how morphological traits change over time. There are certain rules regarding how DNA changes; however, this statement is more related to the principle of maximum likelihood.
21. Birds and mammals have a four-chambered heart, but reptiles have a three-chambered heart. How does this
fact affect the construction of phylogenetic trees for these groups? ( Concept 26.3)
Your Answer: This represents a problem with the principle of parsimony, rather than a problem with the analogy-homology issue.
Correct Answer:
The most likely tree is not always the most parsimonious.
No. Just the opposite is true. A four-chambered heart must have developed independently in birds and mammals. To be the most accurate, a phylogenetic tree should represent several different characters to overcome problems with analogy and homology.
22. If you wanted to determine the lineage of plants that have evolved on a relatively young archipelago—
approximately 15,000 years old—what type of nucleic acid should you compare? ( Concept 26.4)
Your Answer: mRNA
Correct Answer:
mtDNA
No. Messenger RNA would not be the most likely choice.
23. Paralogous genes _____. ( Concept 26.4)
Your Answer: are responsible for the differences in beta hemoglobin in humans and mice
Correct Answer:
result from gene duplication
No. Beta hemoglobin genes are orthologous.
24. What is the evolutionary significance of paralogous genes? ( Concept 26.4)
Your Answer: They give the absolute time that two species diverged.
Correct Answer:
They increase the size of the genome and provide more opportunity for the evolution of novel characteristics.
No. Because paralogous genes result from gene duplication, the duplicated genes can diverge from each other without speciation occurring. Paralogous genes are not very useful in looking at when species diverge.
25. What is the evolutionary significance of orthologous genes? ( Concept 26.4)
Your Answer: They always provide the evolutionary explanation with the maximum parsimony.
Correct Answer:
The high percentage of orthologous genes found in vastly different organisms emphasizes the many biochemical and developmental pathways shared by all organisms.
No. It is not always the case that straight line inheritance provides the most parsimonious explanation for observed phylogenetic trends.
26. Which is an assumption of the neutral theory? ( Concept 26.5)
Your Answer: Differences in the rate of the clock in different genes are a function of how important each gene is.
Correct Answer:
Much evolutionary change in genes and proteins has no effect on fitness and therefore is not influenced by Darwinian selection.
No. This is an assumption of the neutral theory, but there is a better answer.
27. The idea of using molecules as clocks to time evolutionary events is very attractive, but there are many
problems in actually applying the technique. What seems to be the best way to get reliable results? ( Concept 26.5)
Your Answer: It is important to use one gene in which the changes are clearly neutral.
Correct Answer:
It is important to use as many genes as possible. With this approach, fluctuations in evolutionary rate will tend to average out.
No. It is difficult to determine whether all the changes in a gene are neutral; therefore, it is better to use several genes so that directional changes may average out.
28. By applying a molecular clock, researchers at Los Alamos National Laboratory have proposed that the first
HIV-1 M invasion into humans occurred in the _____. ( Concept 26.5)
Your Answer:
1930s
Correct. This is the point in time when some scientists estimate that HIV jumped from simians to humans.
29. To which domain is the domain Eukarya (the domain to which humans belong) most closely related? (
Concept 26.6)
Your Answer: Archaea
Correct Answer:
It is not clear whether eukaryotes are more closely related to bacteria or archaea.
No. Although rRNA genes indicate that eukaryotes and archaea are more closely related, genes that influence
metabolism indicate a closer relationship between eukaryotes and bacteria.
30. Universal phylogenetic trees built from different genes sometimes give inconsistent results. What basic assumption on which phylogenetic trees are based has probably been violated during the history of life? (
Concept 26.6)
Your Answer:
Genes are passed vertically from one generation to the next.
Correct. Phylogenetic trees assume vertical gene transfer, but many organisms also use horizontal gene transfer. Many scientists postulate that horizontal gene transfer was far more prevalent during the early history of life.
![[XLS] · Web view1 1 1 2 3 1 1 2 2 1 1 1 1 1 1 2 1 1 1 1 1 1 2 1 1 1 1 2 2 3 5 1 1 1 1 34 1 1 1 1 1 1 1 1 1 1 240 2 1 1 1 1 1 2 1 3 1 1 2 1 2 5 1 1 1 1 8 1 1 2 1 1 1 1 2 2 1 1 1 1](https://static.documents.pub/doc/80x56/5ad1d2817f8b9a05208bfb6d/xls-view1-1-1-2-3-1-1-2-2-1-1-1-1-1-1-2-1-1-1-1-1-1-2-1-1-1-1-2-2-3-5-1-1-1-1.jpg)
![1 $SU VW (G +LWDFKL +HDOWKFDUH %XVLQHVV 8QLW 1 X ñ 1 … · 2020. 5. 26. · 1 1 1 1 1 x 1 1 , x _ y ] 1 1 1 1 1 1 ¢ 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1](https://static.documents.pub/doc/80x56/5fbfc0fcc822f24c4706936b/1-su-vw-g-lwdfkl-hdowkfduh-xvlqhvv-8qlw-1-x-1-2020-5-26-1-1-1-1-1-x.jpg)
