Campbell’s Biology, 9e (Reece et al.)
Chapter 25 The History of Life on Earth
Earth is a stage upon which the drama of evolution unfolds. Alas, the stage is moving! Several of the
sets of scenario questions in this chapter focus on the effect continental drift has had on the history of
life on Earth, including a new set of scenario questions pertaining to the evolution of life on the
Hawaiian Islands.
Multiple-Choice Questions
1) Which of the following factors weaken(s) the hypothesis of abiotic synthesis of organic monomers in
early Earth’s atmosphere?
1. the relatively short time between intense meteor bombardment and the appearance of the first life-
forms
2. the lack of experimental evidence that organic monomers can form by abiotic synthesis
3. uncertainty about which gases comprised early Earth’s atmosphere
A) 1 only
B) 2 only
C) 1 and 2
D) 1 and 3
E) 2 and 3
2) How were conditions on the early Earth of more than 3 billion years ago different from those on
today’s Earth?
A) Only early Earth was intensely bombarded by large space debris.
B) Only early Earth had an oxidizing atmosphere.
C) Less ultraviolet radiation penetrated early Earth’s atmosphere.
D) Early Earth’s atmosphere had significant quantities of ozone.
3) What is true of the amino acids that might have been delivered to Earth within carbonaceous
chondrites?
A) They had the same proportion of L and D isomers as Earth does today.
B) Their abundance would have been dramatically reduced upon passage through early Earth’s oxidizing
atmosphere.
C) There were more kinds of amino acids on the chondrites than are found in living organisms today.
D) They were delivered in the form of polypeptides.
4) Which of the following is the correct sequence of events in the origin of life?
I. formation of protobionts
II. synthesis of organic monomers
III. synthesis of organic polymers
IV. formation of DNA-based genetic systems
A) I, II, III, IV
B) I, III, II, IV
C) II, III, I, IV
D) II, III, IV, I
5) Which of the following is a defining characteristic that all protobionts had in common?
A) the ability to synthesize enzymes
B) a surrounding membrane or membrane-like structure
C) RNA genes
D) the ability to replicate RNA
6) The first genes on Earth were probably
A) DNA produced by reverse transcriptase from abiotically produced RNA.
B) DNA molecules whose information was transcribed to RNA and later translated in polypeptides.
C) auto-catalytic RNA molecules.
D) oligopeptides located within protobionts.
7) The synthesis of new DNA requires the prior existence of oligonucleotides to serve as primers. On
Earth, these primers are small RNA molecules. This latter observation is evidence in support of the
hypothesized existence of
A) a snowball Earth.
B) earlier genetic systems than those based on DNA.
C) the abiotic synthesis of organic monomers.
D) the delivery of organic matter to Earth by meteors and comets.
E) the endosymbiotic origin of mitochondria and chloroplasts.
8) Several scientific laboratories across the globe are involved in research concerning the origin of life
on Earth. Which of these questions is currently the most problematic and would have the greatest impact
on our understanding if we were able to answer it?
A) How can amino acids, simple sugars, and nucleotides be synthesized abiotically?
B) How can RNA molecules catalyze reactions?
C) How did RNA sequences come to carry the code for amino acid sequences?
D) How could polymers involving lipids and/or proteins form membranes in aqueous environments?
E) How can RNA molecules act as templates for the synthesis of complementary RNA molecules?
9) If natural selection in a particular environment favored genetic systems that permitted the production
of daughter “cells” that were genetically dissimilar from the mother “cells,” then one should expect
selection for which of the following?
I. polynucleotide polymerase with low mismatch error rates
II. polynucleotide polymerases without proofreading capability
III. batteries of efficient polynucleotide repair enzymes
IV. polynucleotide polymerases with proofreading capability
V. polynucleotide polymerases with high mismatch error rates
A) I only
B) I and IV
C) I, III, and IV
D) II and V
E) II, III and V
10) If the half-life of carbon-14 is about 5,730 years, then a fossil that has one-sixteenth the normal
proportion of carbon-14 to carbon-12 should be about how many years old?
A) 1,400
B) 2,800
C) 11,200
D) 16,800
E) 22,900
11) Which measurement(s) would help determine absolute dates by radiometric means?
A) the accumulation of the daughter isotope
B) the loss of parent isotopes
C) the loss of daughter isotopes
D) Three of the responses above are correct.
E) Two of the responses above are correct.
12) Approximately how far back in time does the fossil record extend?
A) 3.5 million years
B) 5.0 million years
C) 3.5 billion years
D) 5.0 billion years
13) What is true of the fossil record of mammalian origins?
A) It is a good example of punctuated equilibrium.
B) It shows that mammals and birds evolved from the same kind of dinosaur.
C) It includes transitional forms with progressively specialized teeth.
D) It indicates that mammals and dinosaurs did not overlap in geologic time.
E) It includes a series that shows the gradual change of scales into fur.
14) If a fossil is encased in a stratum of sedimentary rock without any strata of igneous rock (for
example, lava, volcanic ash) nearby, then it should be
A) easy to determine the absolute age of the fossil, because the radioisotopes in the sediments will not
have been “reset” by the heat of the igneous rocks.
B) easy to determine the absolute age of the fossil, because the igneous rocks will not have physically
obstructed the deposition of sediment of a single age next to the fossil.
C) easy to determine, as long as there is enough metamorphic rock nearby.
D) difficult to determine the absolute age of the fossil, because the “marker fossils” common to igneous
rock will be absent.
E) difficult to determine the absolute age of the fossil, because radiometric dating of sedimentary rock is
less accurate than that of igneous rock.
15) An early consequence of the release of oxygen gas by plant and bacterial photosynthesis was to
A) generate intense lightning storms.
B) change the atmosphere from oxidizing to reducing.
C) make it easier to maintain reduced molecules.
D) cause iron in ocean water and terrestrial rocks to rust (oxidize).
E) prevent the formation of an ozone layer.
16) Which of the following statements provides the strongest evidence that prokaryotes evolved before
eukaryotes?
A) Prokaryotic cells lack nuclei.
B) The meteorites that have struck Earth contain fossils only of prokaryotes.
C) Laboratory experiments have produced liposomes abiotically.
D) Liposomes closely resemble prokaryotic cells.
E) The oldest fossilized cells resemble prokaryotes.
17) What is true of the Cambrian explosion?
A) There are no fossils in geological strata that are older than the Cambrian explosion.
B) Only the fossils of microorganisms are found in geological strata older than the Cambrian explosion.
C) The Cambrian explosion is evidence for the instantaneous creation of life on Earth.
D) The Cambrian explosion marks the appearance of filter-feeding animals in the fossil record.
E) Recent evidence supports the contention that the Cambrian explosion may not have been as
“explosive” as was once thought.
18) What is thought to be the correct sequence of these events, from earliest to most recent, in the
evolution of life on Earth?
1. origin of mitochondria
2. origin of multicellular eukaryotes
3. origin of chloroplasts
4. origin of cyanobacteria
5. origin of fungal-plant symbioses
A) 4, 3, 2, 1, 5
B) 4, 1, 2, 3, 5
C) 4, 1, 3, 2, 5
D) 4, 3, 1, 5, 2
E) 4, 3, 1, 2, 5
19) If it were possible to conduct sophisticated microscopic and chemical analyses of microfossils found
in 3.2-billion-year-old stromatolites, then one should be surprised to observe evidence of which of the
following within such microfossils?
I. double-stranded DNA
II. a nuclear envelope
III. a nucleoid
IV. a nucleolus
V. ribosomes
A) II only
B) III only
C) II and IV
D) II, III, and IV
E) all five of these
20) Recent evidence indicates that the first major diversification of multicellular eukaryotes may have
coincided in time with the
A) origin of prokaryotes.
B) switch to an oxidizing atmosphere.
C) melting that ended the “snowball Earth” period.
D) origin of multicellular organisms.
E) massive eruptions of deep-sea vents.
21) Which of these observations gives the most support to the endosymbiotic theory for the origin of
eukaryotic cells?
A) the existence of structural and molecular differences between the plasma membranes of prokaryotes
and the internal membranes of mitochondria and chloroplasts
B) the similarity in size between the cytosolic ribosomes of prokaryotes and the ribosomes within
mitochondria and chloroplasts
C) the size disparity between most prokaryotic cells and most eukaryotic cells
D) the observation that some eukaryotic cells lack mitochondria
22) Which event is nearest in time to the end of the period known as snowball Earth?
A) oxygenation of Earth’s seas and atmosphere
B) evolution of mitochondria
C) Cambrian explosion
D) evolution of true multicellularity
E) Permian extinction
23) The snowball Earth hypothesis provides a possible explanation for the
A) diversification of animals during the late Proterozoic era.
B) oxygenation of Earth’s seas and atmosphere.
C) colonization of land by plants and fungi.
D) origin of oxygen-releasing photosynthesis.
E) existence of prokaryotes around hydrothermal vents on the ocean floor.
24) Which of the following characteristics should have been possessed by the first animals to colonize
land?
1. were probably herbivores (ate photosynthesizers)
2. had four appendages
3. had the ability to resist dehydration
4. had lobe-finned fishes as ancestors
5. were invertebrates
A) 3 only
B) 3 and 5
C) 1, 3, and 5
D) 2, 3, and 4
E) 1, 2, 3, and 4
25) The first terrestrial organisms probably were considered which of the following?
1. burrowers
2. photosynthetic
3. multicellular
4. prokaryotes
5. eukaryotes
6. plants and their associated fungi
A) 2 and 4
B) 3 and 5
C) 1, 3, and 5
D) 2, 3, and 6
E) 2, 3, 5, and 6
26) If two continents converge and are united, then the collision should cause
A) a net loss of intertidal zone and coastal habitat.
B) the extinction of any species adapted to intertidal and coastal habitats.
C) an overall decrease in the surface area located in the continental interior.
D) a decrease in climatic extremes in the interior of the new supercontinent.
E) the maintenance of the previously existing ocean currents and wind patterns.
27) The major evolutionary episode corresponding most closely in time with the formation of Pangaea
was the
A) Cambrian explosion.
B) Permian extinctions.
C) Pleistocene ice ages.
D) Cretaceous extinctions.
28) On the basis of their morphologies, how might Linnaeus have classified the Hawaiian silverswords?
A) He would have placed them all in the same species.
B) He would have classified them the same way that modern botanists do.
C) He would have placed them in more species than modern botanists do.
D) He would have used evolutionary relatedness as the primary criterion for their classification.
29) An organism has a relatively large number of Hox genes in its genome. Which of the following is
true of this organism?
A) These genes are fundamental, and are expressed in all cells of the organism.
B) The organism must have multiple paired appendages along the length of its body.
C) The organism has the genetic potential to have a relatively complex anatomy.
D) Most of its Hox genes owe their existence to gene fusion events.
E) Its Hox genes cooperate to bring about sexual maturity at the proper stage of development.
30) Bagworm moth caterpillars feed on evergreens and carry a silken case or bag around with them in
which they eventually pupate. Adult female bagworm moths are larval in appearance; they lack the
wings and other structures of the adult male and instead retain the appearance of a caterpillar even
though they are sexually mature and can lay eggs within the bag. This is a good example of
A) allometric growth.
B) paedomorphosis.
C) sympatric speciation.
D) adaptive radiation.
E) changes in homeotic genes.
31) The loss of ventral spines by modern freshwater sticklebacks is due to natural selection operating on
the phenotypic effects of Pitx1 gene
A) duplication (gain in number).
B) elimination (loss).
C) mutation (change).
D) silencing (loss of expression).
32) Larval flies (maggots) express the Ubx gene in all of their segments, and thereby lack appendages. If
this same gene continued to be expressed throughout subsequent developmental stages, except in the
head region, and if the result was a fit, sexually mature organism that still strongly resembled a maggot,
this would be an example of
A) paedomorphosis.
B) homochrony.
C) heterochrony.
D) Two of the responses above are correct.
33) How many of the following statements concerning the loss of hind limbs during whale evolution are
true?
1. It is well documented by a series of transitional fossils.
2. It explains why modern whales have vestigial pelvic girdles.
3. It involved changes in the sequence or expression of Hox genes.
4. It is an example of macroevolution.
5. It, and the loss of limbs by snakes, are an example of similar adaptations to a similar environment.
A) Only one statement is true.
B) Two statements are true.
C) Three statements are true.
D) Four statements are true.
E) All five statements are true.
34) The existence of the phenomenon of exaptation is most closely associated with which of the
following observations that natural selection cannot fashion perfect organisms?
A) Natural selection and sexual selection can work at cross-purposes to each other.
B) Evolution is limited by historical constraints.
C) Adaptations are often compromises.
D) Chance events affect the evolutionary history of populations in environments that can change
unpredictably.
35) One explanation for the evolution of insect wings suggests that wings began as lateral extensions of
the body that were used as heat dissipaters for thermoregulation. When they had become sufficiently
large, these extensions became useful for gliding through the air, and selection later refined them as
flight-producing wings. If this hypothesis is correct, modern insect wings could best be described as
A) adaptations.
B) mutations.
C) exaptations.
D) isolating mechanisms.
E) examples of natural selection’s predictive ability.
36) If one organ is an exaptation of another organ, then what must be true of these two organs?
A) They are both vestigial organs.
B) They are both homologous organs.
C) They are undergoing convergent evolution.
D) They are found together in the same hybrid species.
E) They have the same function.
37) Many species of snakes lay eggs. However, in the forests of northern Minnesota where growing
seasons are short, only live-bearing snake species are present. This trend toward species that perform
live birth in a particular environment is an example of
A) natural selection.
B) sexual selection.
C) species selection.
D) goal direction in evolution.
E) directed selection.
38) In the 5–7 million years that the hominid lineage has been diverging from its common ancestor with
the great apes, dozens of hominid species have arisen, often with several species coexisting in time and
space. As recently as 30,000 years ago, Homo sapiens coexisted with Homo neanderthalensis. Both
species had large brains and advanced intellects. The fact that these traits were common to both species
is most easily explained by which of the following?
A) species selection
B) uniformitarianism
C) sexual selection
D) convergent evolution
39) The existence of evolutionary trends, such as increasing body sizes among horse species, is evidence
that
A) a larger volume-to-surface area ratio is beneficial to all mammals.
B) an unseen guiding force is at work.
C) evolution always tends toward increased complexity or increased size.
D) in particular environments, similar adaptations can be beneficial in more than one species.
E) evolution generally progresses toward some predetermined goal.
40) Fossil evidence indicates that several kinds of flightless dinosaurs possessed feathers. If some of
these feather-bearing dinosaurs incubated clutches of eggs in carefully constructed nests, this might be
evidence supporting the claim that
A) dinosaurs were as fully endothermal (warm-blooded) as modern birds and mammals.
B) their feathers originally served as insulation, and only later became flight surfaces.
C) the earliest reptiles could fly, and the feathers of flightless dinosaurs were vestigial flight surfaces.
D) the feathers were plucked from the bodies of other adults to provide nest-building materials.
E) all fossils with feathers are actually some kind of bird.
12
Art Questions
41) Several scientific laboratories across the globe are involved in research concerning the origin of life
on Earth. Which graph below, if the results were produced abiotically, would have the greatest promise
for revealing important information about the origin of Earth’s first genetic system?
A)
B)
C)
D)
The following questions refer to the description and figure below.
The figure represents a cross section of the sea floor through a mid-ocean rift valley, with alternating
patches of black and white indicating sea floor with reversed magnetic polarities. At the arrow labeled
“I” (the rift valley), the igneous rock of the sea floor is so young that it can be accurately dated using
carbon-14 dating. At the arrow labeled “III,” however, the igneous rock is about 1 million years old, and
potassium-40 dating is typically used to date such rocks. Note: The horizontal arrows indicate the
direction of sea-floor spreading, away from the rift valley.
Figure 25.1
42) Assuming that the rate of sea-floor spreading was constant during the 1-million-year period depicted
above, Earth’s magnetic field has undergone reversal at an average rate of once every
A) 10,000 years.
B) 25,000 years.
C) 100,000 years.
D) 250,000 years.
E) 1,000,000 years.