ch. 25, 28, 31, (TEST 1) Flashcards Preview

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Flashcards in ch. 25, 28, 31, (TEST 1) Deck (208):
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

D) 1 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.

A) Only early Earth was intensely bombarded by large space debris.

3

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.

C) There were more kinds of amino acids on the chondrites than are found in living organisms today.

4

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

C) II, III, I, IV

5

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

B) a surrounding membrane or membrane-like structure

6

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.

C) auto-catalytic RNA molecules.

7

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.

B) earlier genetic systems than those based on DNA.

8

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?

C) How did RNA sequences come to carry the code for amino acid sequences?

9

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

D) II 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

E) 22,900

11

Which measurement 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) all three of these
E) only A and B

E) only A and B

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

C) 3.5 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.

C) It includes transitional forms with progressively specialized teeth.

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.

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.

D) cause iron in ocean water and terrestrial rocks to rust (oxidize).

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.

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.

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

C) 4, 1, 3, 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

C) II and IV

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.

C) melting that ended the "snowball Earth" period.

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

B) the similarity in size between the cytosolic ribosomes of prokaryotes and the ribosomes within mitochondria and chloroplasts

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

C) Cambrian explosion

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.

A) diversification of animals during the late Proterozoic era.

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

C) 1, 3, and 5

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

A) 2 and 4

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.

A) a net loss of intertidal zone and coastal habitat.

27

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.

C) He would have placed them in more species than modern botanists do.

28

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.

C) The organism has the genetic potential to have a relatively complex anatomy.

29

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.

B) paedomorphosis.

30

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).

D) silencing (loss of expression).

31

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.

D) Two of the responses above are correct.

32

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.

D) Four statements are true.

33

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.

B) Evolution is limited by historical constraints.

34

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.

C) exaptations.

35

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.

B) They are both homologous organs.

36

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.

C) species selection.

37

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

A) species selection

38

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.

D) in particular environments, similar adaptations can be beneficial in more than one species.

39

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.

B) their feathers originally served as insulation, and only later became flight surfaces.

40

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.

D) 250,000 years.

41

Which of the following reasons may explain why the sediment core lacks fossils of dragonflies with 3-feet wingspans?
1. This particular sediment core includes the correct stratum, but the part of the stratum captured by the core lacks such fossils.
2. The sea was not present at this site during the time that 3-feet dragonflies existed.
3. Dragonflies have no hard parts, such as exoskeletons, to fossilize.
4. The sediments containing these fossils at this site may have been eroded away during a time when the sea had receded from this site.
5. Dragonflies are terrestrial; therefore, fossils of terrestrial organisms should not be expected in the sediments of seas.
A) 1 only
B) 3 only
C) 5 only
D) 2 or 4
E) 1, 2, or 4

E) 1, 2, or 4

42

In order to properly interpret sediment cores, it is necessary to apply the principle of
A) catastrophism.
B) superposition.
C) punctuated equilibrium.
D) uniformitarianism.
E) gradualism.

B) superposition.

43

Assuming the existence of fossilized markers for each of the following chemicals, what is the sequence in which they should be found in this sediment core, working from ancient sediments to recent sediments?
1. chitin coupled with protein
2. chlorophyll
3. bone
4. cellulose
A) 2, 4, 3, 1
B) 2, 4, 1, 3
C) 4, 2, 1, 3
D) 4, 2, 3, 1

B) 2, 4, 1, 3

44

In order to assign absolute dates to fossils in this sediment core, it would be most helpful if
A) we knew the order in which the fossils occurred in the core.
B) the sediments had not been affected by underwater currents during their deposition.
C) volcanic ash layers were regularly interspersed between the sedimentary strata.
D) metamorphic rock strata alternated with sedimentary rock strata.
E) fossils throughout the column had equal ratios of a parental radioisotope to its daughter isotope.

C) volcanic ash layers were regularly interspersed between the sedimentary strata.

45

Hawaii is the most southeastern of the seven islands and is also closest to the sea-floor spreading center from which the Pacific plate originates, which lies about 5,600 km further to the southeast. Assuming equal sedimentation rates, what should be the location of the thickest sediment layer and, thus, the area with the greatest diversity of fossils above the oceanic crust?
A) between the island of Hawaii and the sea-floor spreading center
B) around the base of the island of Hawaii
C) around the base of Kauai, the oldest of the Hawaiian islands
D) where the islands are most concentrated (highest number of islands per unit surface area)

C) around the base of Kauai, the oldest of the Hawaiian islands

46

Soon after the island of Hawaii rose above the sea surface (somewhat less than 1 million years ago), the evolution of life on this new island should have been most strongly influenced by
A) genetic bottleneck.
B) sexual selection.
C) habitat differentiation.
D) founder effect.

D) founder effect.

47

Upon being formed, oceanic islands, such as the Hawaiian Islands, should feature what characteristic, leading to which phenomenon?
A) mass extinctions, leading to bottleneck effect
B) major evolutionary innovations, leading to rafting to nearby continents
C) a variety of empty ecological niches, leading to adaptive radiation
D) adaptive radiation, leading to founder effect
E) overcrowding, leading to rafting to nearby lands

C) a variety of empty ecological niches, leading to adaptive radiation

48

Fossilized stromatolites
A) all date from 2.7 billion years ago.
B) formed around deep-sea vents.
C) resemble structures formed by bacterial communities that are found today in some warm, shallow, salty bays.
D) provide evidence that plants moved onto land in the company of fungi around 500 million years ago.
E) contain the first undisputed fossils of eukaryotes and date from 2.1 billion years ago.

C) resemble structures formed by bacterial communities that are found today in some warm, shallow, salty bays.

49

The oxygen revolution changed Earth's environment dramatically. Which of the following took advantage of the presence of free oxygen in the oceans and atmosphere?
A) the evolution of cellular respiration, which used oxygen to help harvest energy from organic molecules
B) the persistence of some animal groups in anaerobic habitats
C) the evolution of photosynthetic pigments that protected early algae from the corrosive effects of oxygen
D) the evolution of chloroplasts after early protists incorporated photosynthetic cyanobacteria
E) the evolution of multicellular eukaryotic colonies from communities of prokaryotes

A) the evolution of cellular respiration, which used oxygen to help harvest energy from organic molecules

50

Which factor most likely caused animals and plants in India to differ greatly from species in nearby southeast Asia?
A) The species have become separated by convergent evolution.
B) The climates of the two regions are similar.
C) India is in the process of separating from the rest of Asia.
D) Life in India was wiped out by ancient volcanic eruptions.
E) India was a separate continent until 45 million years ago.

E) India was a separate continent until 45 million years ago.

51

Adaptive radiations can be a direct consequence of four of the following five factors. Select the exception.
A) vacant ecological niches
B) genetic drift
C) colonization of an isolated region that contains suitable habitat and few competitor species
D) evolutionary innovation
E) an adaptive radiation in a group of organisms (such as plants) that another group uses as food

B) genetic drift

52

Which of the following steps has not yet been accomplished by scientists studying the origin of life?
A) synthesis of small RNA polymers by ribozymes
B) abiotic synthesis of polypeptides
C) formation of molecular aggregates with selectively permeable membranes
D) formation of protocells that use DNA to direct the polymerization of amino acids
E) abiotic synthesis of organic molecules

D) formation of protocells that use DNA to direct the polymerization of amino acids

53

A genetic change that caused a certain Hox gene to be expressed along the tip of a vertebrate limb bud instead of farther back helped make possible the evolution of the tetrapod limb. This type of change is illustrative of
A) the influence of environment on development.
B) paedomorphosis.
C) a change in a developmental gene or its regulation that altered the spatial organization of body parts.
D) heterochrony.
E) gene duplication.

C) a change in a developmental gene or its regulation that altered the spatial organization of body parts.

54

A swim bladder is a gas-filled sac that helps fish maintain buoyancy. The evolution of the swim bladder from lungs of an ancestral fish is an example of
A) an evolutionary trend.
B) exaptation.
C) changes in Hox gene expression.
D) paedomorphosis.
E) adaptive radiation.

B) exaptation.

55

Which gas was least abundant in Earthʹs early atmosphere, prior to 2 billion years ago?
A) O2 B) CO2 C) CH4
D) H2O E) NH3

A) O2

56

In their laboratory simulations of the early Earth, Miller and Urey observed the abiotic synthesis of
A) amino acids.
B) complex organic polymers.
C) DNA.
D) liposomes.
E) genetic systems.

A) amino acids.

57

Which of the following has not yet been synthesized in laboratory experiments studying the origin of life?
A) liposomes
B) liposomes with selectively permeable membranes
C) oligopeptides and other oligomers
D) protobionts that use DNA to program protein synthesis
E) amino acids

D) protobionts that use DNA to program protein synthesis

58

In what way were conditions on the early Earth of more than 3 billion years ago different from those on todayʹs Earth?
A) Only early Earth had water vapor in its atmosphere.
B) Only early Earth was intensely bombarded by large space debris.
C) Only early Earth had an oxidizing atmosphere.
D) Less ultraviolet radiation penetrated Earthʹs early atmosphere.
E) Earthʹs early atmosphere had significant quantities of ozone.

B) Only early Earth was intensely bombarded by large space debris.

59

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) The proportion of the amino acids was similar to those produced in the Miller-Urey
experiment.
C) There were fewer kinds of amino acids on the chondrites than are found in living
organisms today.
D) They were delivered in the form of polypeptides.

B) The proportion of the amino acids was similar to those produced in the Miller-Urey
experiment.

60

Although absolute distinctions between the ʺmost evolvedʺ protobiont and the first living cell are unclear, biologists generally agree that one major difference is that the typical protobiont could not
A) possess a selectively permeable membrane boundary. B) perform osmosis.
C) grow in size.
D) perform controlled, precise reproduction.
E) absorb compounds from the external environment.

D) perform controlled, precise reproduction.

61

RNA molecules can both carry genetic information and be catalytic. This supports the proposal that
A) RNA was the first hereditary information.
B) protobionts had an RNA membrane.
C) RNA could make energy.
D) free nucleotides would not have been necessary ingredients in the synthesis of new
RNA molecules.
E) RNA is a polymer of amino acids.

A) RNA was the first hereditary information.

62

What probably accounts for the switch to DNA-based genetic systems during the evolution of life on Earth?
A) DNA is chemically more stable and replicates with fewer errors (mutations) than RNA.
B) Only DNA can replicate during cell division.
C) RNA is too involved with translation of proteins and cannot provide multiple
functions.
D) DNA forms the rod-shaped chromosomes necessary for cell division.
E) Replication of RNA occurs too slowly.

A) DNA is chemically more stable and replicates with fewer errors (mutations) than RNA.

63

If relatively small carbonaceous chondrites from space were a significant source of Earthʹs original amino acids, then which two of these would have been most important in permitting their organic materials to survive impact with Earth?
I. Carbonaceous chondrites must contain no D-amino acids.
II. Earthʹs early atmosphere must have had little free oxygen.
III. The chondrites must have arrived on Earth before 4.2 billion years ago.
IV. Earthʹs early atmosphere must have been dense enough to dramatically slow the
chondrites before they impacted.
V. The chondrites must have impacted land, rather than a large body of water.
A) I & II B) II & III C) II&IV
D) II & V E) III & IV

C) II&IV

64

How many half-lives should have elapsed if 6.25% of the parent isotope remains in a fossil at the time of analysis?
A) one B) two C) three D) four E) five

D) four

65

Approximately how far back in time does the fossil record extend? A) 6,000 years
B) 3,500,000 years
C) 6,000,000 years
D) 3,500,000,000 years
E) 5,000,000,000,000 years

D) 3,500,000,000 years

66

Arrange these events from earliest to most recent.
1. emission of lava in what is now Siberia at time of Permian extinctions
2. emission of lava that solidified at the same time as iron-bearing terrestrial rocks began to rust
3. emission of lava that solidified at the same time as rusted iron precipitated from seawater
4. emission of lava in what is now India at time of Cretaceous extinctions
A) 3, 1, 2, 4
B) 3, 2, 1, 4
C) 3,1,4,2
D) 1, 3, 2, 4
E) 1, 2, 3, 4

B) 3, 2, 1, 4

67

Which free-living cells were the earliest contributors to the formation of Earthʹs oxidizing atmosphere?
A) cyanobacteria
B) chloroplasts
C) mitochondria
D) seaweeds
E) endosymbionts

A) cyanobacteria

68

Which of these observations fails to support 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 existence of size differences between the cytosolic ribosomes of eukaryotes and the ribosomes within mitochondria and chloroplasts
C) the existence of size differences between some prokaryotic cells and mitochondria
D) the existence of rRNA sequence differences between the cytosolic ribosomes of
eukaryotes and the ribosomes within mitochondria and chloroplasts

A) the existence of structural and molecular differences between the plasma membranes of prokaryotes and the internal membranes of mitochondria and chloroplasts

69

A major evolutionary episode that corresponds in time most closely with the formation of Pangaea was the
A) origin of humans.
B) Cambrian explosion.
C) Permian extinctions.
D) Pleistocene ice ages.
E) Cretaceous extinctions.

C) Permian extinctions.

70

The observation that tusks were limited to males in several species, and were apparently not used in food-gathering, is evidence that the tusks probably
A) were used by males during the sex act.
B) served as heat-dissipation structures.
C) are homologous to claws.
D) were insignificant to the survival and/or reproduction of dicynodonts.
E) were maintained as the result of sexual selection.

E) were maintained as the result of sexual selection.

71

Which of these is the most likely explanation for the existence of dicynodont fossils on modern-day Antarctica?
A) They arrived there aboard ʺraftsʺ of vegetation, and quickly adapted to the bitterly cold climate.
B) Earthʹs polar regions were once so warm (especially immediately after the ʺsnowball Earth periodʺ) that reptiles and mammal-like reptiles flourished there.
C) The landmass that is now the Antarctic continent was formerly located at a more-northerly position, and was also united to other landmasses.
D) Dicynodonts originated on the island continent of Antarctica and went extinct as the continent migrated to its current position at the South Pole.

C) The landmass that is now the Antarctic continent was formerly located at a more-northerly position, and was also united to other landmasses.

72

Dicynodonts survived the Permian extinction and, therefore, existed during both the A) Paleozoic and Mesozoic eras.
B) Proterozoic and Archaean eons. C) Proterozoic and Phanerozoic eons. D) Mesozoic and Cenozoic eras.
E) Carboniferous and Permian periods.

A) Paleozoic and Mesozoic eras.

73

There are at least a dozen known species in the extinct genus Lystrosaurus. If each species was suited to a quite different environment, then this relatively large number of species is likely due to
A) sexual selection.
B) adaptive radiation.
C) heterochrony. D) polyploidy.
E) species selection.

B) adaptive radiation.

74

The dicynodonts survived the mass extinction that was most closely correlated in time, if not in cause, with
A) snowball Earth.
B) a large (10 km) meteor striking the Earth.
C) an intense period of sun-spot formation, with subsequent increase in solar radiation.
D) the formation of Pangaea and lava flows that covered large portions of Pangaea.
E) the pleistocene Ice Age.

D) the formation of Pangaea and lava flows that covered large portions of Pangaea.

75

As rat pups mature, the growth of their snouts and tails outpaces growth of the rest of their bodies, producing the appearance of sexually mature males. It is found that sexually mature female rats prefer to mate with mutant, sexually mature males that possess snouts and tails with juvenile proportions. Which of the following terms is (are) appropriately applied to this situation?
A) sexual selection
B) paedomorphosis
C) allometric growth
D) B and C only
E) A, B, and C

E) A, B, and C

76

A hypothetical mutation in a squirrel population produces organisms with eight legs rather than four. Further, these mutant squirrels survive, successfully invade new habitats, and eventually give rise to a new species. The initial event, giving rise to extra legs, would be a good example of
A) punctuated equilibrium.
B) species selection.
C) habitat selection.
D) changes in homeotic genes.
E) allometry.

D) changes in homeotic genes.

77

Fossilized stromatolites
A) all date from 2.7 billion years ago.
B) formed around deep-sea vents.
C) resemble structures formed by bacterial communities that are found today in some
warm, shallow, salty bays.
D) provide evidence that plants moved onto land in the company of fungi around 500
million years ago.
E) contain the first undisputed fossils of eukaryotes and date from 2.1 billion years ago.

C) resemble structures formed by bacterial communities that are found today in some
warm, shallow, salty bays.

78

Select the factor most likely to have caused the animals and plants of India to differ greatly from species in nearby Southeast Asia.
A) The species have become separated by convergent evolution. B) The climates of the two regions are similar.
C) India is in the process of separating from the rest of Asia. D) Life in India was wiped out by ancient volcanic eruptions.
E) India was a separate continent until 55 million years ago.

E) India was a separate continent until 55 million years ago.

79

A genetic change that caused a certain Hox gene to be expressed along the tip of a vertebrate limb bud instead of farther back helped to make possible the evolution of the tetrapod limb. This type of change is illustrative of
A) the influence of environment on development.
B) paedomorphosis.
C) a change in a developmental gene or in its regulation that altered the spatial organization of body parts.
D) heterochrony.
E) gene duplication.

C) a change in a developmental gene or in its regulation that altered the spatial organization of body parts.

80

Protists are alike in that all are
A) unicellular.
B) eukaryotic.
C) symbionts.
D) monophyletic.
E) autotrophic.

B) eukaryotic.

81

Biologists have long been aware that the defunct kingdom Protista is paraphyletic. Which of these statements is both true and consistent with this conclusion?
A) Many species within this kingdom were once classified as monerans.
B) Animals, plants, and fungi arose from different protist ancestors.
C) The eukaryotic condition has evolved only once among the protists, and all eukaryotes are descendants of that first eukaryotic cell.
D) Chloroplasts among various protists are similar to those found in prokaryotes.
E) Some protists, all animals, and all fungi share a protist common ancestor, but these
protists, animals, and fungi are currently assigned to three different kingdoms.

E) Some protists, all animals, and all fungi share a protist common ancestor, but these
protists, animals, and fungi are currently assigned to three different kingdoms.

82

The strongest evidence for the endosymbiotic origin of eukaryotic organelles is the similarity between extant prokaryotes and which of the following?
A) nuclei and chloroplasts
B) mitochondria and chloroplasts
C) cilia and mitochondria
D) mitochondria and nuclei
E) mitochondria and cilia

B) mitochondria and chloroplasts

83

According to the endosymbiotic theory of the origin of eukaryotic cells, how did mitochondria originate?
A) from infoldings of the plasma membrane, coupled with mutations of genes for proteins in energy-transfer reactions
B) from engulfed, originally free-living prokaryotes
C) by secondary endosymbiosis
D) from the nuclear envelope folding outward and forming mitochondrial membranes
E) when a protoeukaryote engaged in a symbiotic relationship with a protobiont

B) from engulfed, originally free-living prokaryotes

84

Which of these statements is false and therefore does not support the hypothesis that certain eukaryotic organelles originated as bacterial endosymbionts? Such organelles
A) are roughly the same size as bacteria.
B) can be cultured on agar, because they make all their own proteins.
C) contain circular DNA molecules.
D) have ribosomes that are similar to those of bacteria.
E) have internal membranes that contain proteins homologous to those of bacterial plasma membranes.

B) can be cultured on agar, because they make all their own proteins.

85

Which process allowed the nucleomorphs of chlorarachniophytes to be first reduced, and then (in a few species) lost altogether, without the loss of any genetic information?
A) conjugation
B) horizontal gene transfer
C) binary fission
D) phagocytosis
E) meiosis

B) horizontal gene transfer

86

Which organisms represent the common ancestor of all photosynthetic plastids found in eukaryotes?
A) autotrophic euglenids
B) diatoms
C) dinoflagellates
D) red algae
E) cyanobacteria

E) cyanobacteria

87

An individual mixotroph loses its plastids, yet continues to survive. Which of the following most likely accounts for its continued survival?
A) It relies on photosystems that float freely in its cytosol.
B) It must have gained extra mitochondria when it lost its plastids.
C) It engulfs organic material by phagocytosis or by absorption.
D) It has an endospore.
E) It is protected by a siliceous case.

C) It engulfs organic material by phagocytosis or by absorption.

88

Which of these was not derived from an ancestral alpha proteobacterium?
A) chloroplast
B) mitochondrion
C) hydrogenosome
D) mitosome
E) kinetoplast

A) chloroplast

89

A biologist discovers a new unicellullar organism that possesses more than two flagella and two small, but equal-sized, nuclei. The organism has reduced mitochondria (mitosomes), no chloroplasts, and is anaerobic. To which clade does this organism probably belong?
A) monera
B) the diplomonads
C) the ciliates
D) protista
E) the euglenids

B) the diplomonads

90

Which two genera have members that can evade the human immune system by frequently changing their surface proteins?
1. Plasmodium
2. Trichomonas
3. Paramecium
4. Trypanosoma
5. Entamoeba
A) 1 and 2 B) 1 and 4 C) 2and3 D) 2 and 4 E) 4 and 5

B) 1 and 4

91

Which statement regarding resistance is false?
A) Many of the oomycetes that cause potato late blight have become resistant to
pesticides.
B) Many of the mosquitoes that transmit malaria to humans have become resistant to
pesticides.
C) Many of the malarial parasites have become resistant to antimalarial drugs.
D) Many humans have become resistant to antimalarial drugs.
E) Trichomonas vaginalis is resistant to the normal acidity of the human vagina.

D) Many humans have become resistant to antimalarial drugs.

92

Which of these taxa contains species that produce potent toxins that can cause extensive fish kills, contaminate shellfish, and poison humans?
A) red algae
B) dinoflagellates
C) diplomonads
D) euglenids
E) golden algae

B) dinoflagellates

93

Which of the following pairs of protists and their characteristics is mismatched?
A) apicomplexans : internal parasites
B) golden algae : planktonic producers
C) euglenozoans : unicellular flagellates
D) ciliates : red tide organisms
E) entamoebas : ingestive heterotrophs

D) ciliates : red tide organisms

94

Which of these statements about dinoflagellates is false?
A) They possess two flagella.
B) Some cause red tides.
C) Their walls are composed of cellulose plates.
D) Many types contain chlorophyll.
E) Their dead cells accumulate on the seafloor, and are mined to serve as a filtering material.

E) Their dead cells accumulate on the seafloor, and are mined to serve as a filtering material.

95

Which group includes members that are important primary producers in ocean food webs, causes red tides that kill many fish, and may even be carnivorous?
A) ciliates
B) apicomplexans
C) dinoflagellates
D) brown algae
E) golden algae

C) dinoflagellates

96

You are given an unknown organism to identify. It is unicellular and heterotrophic. It is motile, using many short extensions of the cytoplasm, each featuring the 9+2 filament pattern. It has well-developed organelles and three nuclei, one large and two small. This organism is most likely to be a member of which group?
A) foraminiferans
B) radiolarians
C) ciliates
D) kinetoplastids
E) slime molds

C) ciliates

97

Which of the following is not characteristic of ciliates?
A) They use cilia as locomotory structures or as feeding structures.
B) They are relatively complex cells.
C) They can exchange genetic material with other ciliates by the process of mitosis.
D) Most live as solitary cells in fresh water.
E) They have two or more nuclei.

C) They can exchange genetic material with other ciliates by the process of mitosis.

98

Which process results in genetic recombination, but is separate from the process wherein the population size of Paramecium increases?
A) budding
B) meiotic division
C) mitotic division
D) conjugation
E) binary fission

D) conjugation

99

Why is the filamentous morphology of the water molds considered a case of convergent evolution with the hyphae (threads) of fungi?
A) Fungi are closely related to the water molds.
B) Body shape reflects ancestor-descendant relationships among organisms.
C) In both cases, filamentous shape is an adaptation for the absorptive nutritional mode of a decomposer.
D) Filamentous body shape is evolutionarily ancestral for all eukaryotes.
E) Both A and B are correct.

C) In both cases, filamentous shape is an adaptation for the absorptive nutritional mode of a decomposer.

100

The Irish potato famine was caused by an organism that belongs to which group?
A) ciliates
B) oomycetes
C) diatoms
D) apicomplexans
E) dinoflagellates

B) oomycetes

101

If one were to apply the most recent technique used to fight potato late blight to the fight against the malarial infection of humans, then one would
A) increase the dosage of the least-expensive antimalarial drug administered to humans.
B) increase the dosage of the most common pesticide used to kill Anopheles mosquitoes.
C) introduce a predator of the malarial parasite into infected humans.
D) use a ʺcocktailʺ of at least three different pesticides against Anopheles mosquitoes.
E) insert genes from a Plasmodium-resistant strain of mosquito into Anopheles mosquitoes.

E) insert genes from a Plasmodium-resistant strain of mosquito into Anopheles mosquitoes.

102

Diatoms are mostly asexual members of the phytoplankton. Diatoms lack any organelles that might have the 9+2 pattern. They obtain their nutrition from functional chloroplasts, and each diatom is encased within two porous, glasslike valves. Which question would be
most important for one interested in the day-to-day survival of individual diatoms?
A) How does carbon dioxide get into these protists with their glasslike valves?
B) How do diatoms get transported from one location on the waterʹs surface layers to
another location on the surface?
C) How do diatoms with their glasslike valves keep from sinking into poorly lit waters?
D) How do diatoms with their glasslike valves avoid being shattered by the action of
waves?
E) How do diatom sperm cells locate diatom egg cells?

C) How do diatoms with their glasslike valves keep from sinking into poorly lit waters?

103

A large seaweed that floats freely on the surface of deep bodies of water would be expected to lack which of the following?
A) thalli
B) bladders
C) blades
D) holdfasts
E) gel-forming polysaccharides

D) holdfasts

104

The following are all characteristic of the water molds (oomycetes) except
A) the presence of filamentous feeding structures.
B) flagellated zoospores.
C) a nutritional mode that can result in the decomposition of dead organic matter.
D) a morphological similarity to fungi that is the result of evolutionary convergence.
E) a feeding plasmodium.

E) a feeding plasmodium.

105

Using dead diatoms to ʺpumpʺ CO2 to the seafloor is feasible only if dead diatoms sink
quickly. Consequently, application of mineral fertilizers, such as iron, should be most effective at times when diatom
A) valves are thickest, and laminarin is being produced rather than oil.
B) valves are thickest, and oil is being produced rather than laminarin.
C) valves are thinnest, and laminarin is being produced rather than oil.
D) valves are thinnest, and oil is being produced rather than laminarin.

A) valves are thickest, and laminarin is being produced rather than oil.

106

Theoretically, which two of the following present the richest potential sources of silica?
1. marine sediments consisting of foram tests
2. marine sediments consisting of diatom cases (valves)
3. marine sediments consisting of radiolarian shells
4. marine sediments consisting of dinoflagellate plates
A) 1 and 2
B) 1 and 4
C) 2and3
D) 2 and 4
E) 3 and 4

C) 2and3

107

Thread-like pseudopods that can perform phagocytosis are generally characteristic of which group?
A) radiolarians and forams
B) gymnamoebas
C) entamoebas
D) amoeboid stage of cellular slime molds
E) oomycetes

A) radiolarians and forams

108

Which of the following produce the dense glassy ooze found in certain areas of the deep-ocean floor?
A) forams
B) dinoflagellates
C) radiolarians
D) ciliates
E) apicomplexans

C) radiolarians

109

A snail-like, coiled, porous test (shell) of calcium carbonate is characteristic of which group?
A) diatoms
B) foraminiferans
C) radiolarians
D) gymnamoebas
E) ciliates

B) foraminiferans

110

Typically as cells grow, their increase in volume outpaces their increase in surface area, and continued survival requires undergoing asexual reproduction to reestablish a healthy surface area to volume ratio. Thus, which of these is least likely to contribute to the ability of a single-celled foraminiferan to grow to a diameter of several centimeters?
A) Its threadlike pseudopods dramatically increase its surface area to volume ratio. B) Its symbiotic algae provide oxygen to the cytoplasm.
C) Its symbiotic algae absorb metabolic waste products from the cytoplasm. D) Its symbiotic algae provide glucose to the cytoplasm.
E) Its calcium carbonate test contributes extra mass.

E) Its calcium carbonate test contributes extra mass.

111

What makes certain red algae appear red?
A) They live in warm coastal waters.
B) They possess pigments that reflect and transmit red light. C) They use red light for photosynthesis.
D) They lack chlorophyll.
E) They contain the pigment bacteriorhodopsin.

B) They possess pigments that reflect and transmit red light.

112

The largest seaweeds belong to which group?
A) red algae
B) green algae
C) brown algae
D) golden algae

C) brown algae

113

The chloroplasts of land plants are thought to have been derived according to which evolutionary sequence?
A) cyanobacteria → green algae → land plants
B) cyanobacteria → green algae → fungi → land plants
C) red algae → brown algae → green algae → land plants D) red algae → cyanobacteria → land plants
E) cyanobacteria → red algae → green algae → land plants

A) cyanobacteria → green algae → land plants

114

The chloroplasts of all of the following are derived from ancestral red algae, except those of
A) golden algae.
B) diatoms.
C) dinoflagellates.
D) green algae.
E) brown algae.

D) green algae.

115

A biologist discovers an alga that is marine, multicellular, and lives at a depth reached only by blue light. This alga probably belongs to which group?
A) red algae
B) brown algae
C) green algae
D) dinoflagellates
E) golden algae

A) red algae

116

Green algae often differ from land plants in that some green algae
A) are heterotrophs.
B) are unicellular.
C) have plastids.
D) have alternation of generations.
E) have cell walls containing cellulose.

B) are unicellular.

117

Which taxon of eukaryotic organisms is thought to be directly ancestral to the plant kingdom?
A) golden algae
B) radiolarians
C) foraminiferans
D) apicomplexans
E) green algae

E) green algae

118

If the Archaeplastidae are eventually designated a kingdom, and if the land plants are excluded from this kingdom, then what will be true of this new kingdom?
A) It will be monophyletic.
B) It will more accurately depict evolutionary relationships than does the current
taxonomy.
C) It will be paraphyletic.
D) It will be a true clade.
E) It will be polyphyletic.

C) It will be paraphyletic.

119

The best evidence for not classifying the slime molds as fungi comes from slime moldsʹ A) DNA sequences.
B) nutritional modes.
C) choice of habitats.
D) physical appearance.
E) reproductive methods.

A) DNA sequences.

120

Which pair of alternatives is highlighted by the life cycle of the cellular slime molds, such as Dictyostelium?
A) prokaryotic or eukaryotic
B) plant or animal
C) unicellular or multicellular D) diploid or haploid
E) autotroph or heterotroph

C) unicellular or multicellular

121

Which of the following correctly pairs a protist with one of its characteristics?
A) diplomonads : micronuclei involved in conjugation
B) ciliates : pseudopods
C) apicomplexans : parasitic
D) gymnamoebas : calcium carbonate test
E) foraminiferans : abundant in soils

C) apicomplexans : parasitic

122

Which of the following statements concerning protists is false?
A) All protists are eukaryotic organisms; many are unicellular or colonial.
B) The primary organism that transmits malaria to humans by its bite is the tsetse fly.
C) All apicomplexans are parasitic.
D) Cellular slime molds have an amoeboid stage that may be followed by a stage during
which spores are produced.
E) Euglenozoans that are mixotrophic contain chloroplasts.

B) The primary organism that transmits malaria to humans by its bite is the tsetse fly.

123

Which of the following is correctly described as a primary producer?
A) oomycete
B) kinetoplastid
C) apicomplexan
D) diatom
E) radiolarian

D) diatom

124

A certain unicellular eukaryote has a siliceous (glasslike) shell and autotrophic nutrition. To which group does it belong?
A) dinoflagellates
B) diatoms
C) brown algae
D) radiolarians
E) oomycetes

B) diatoms

125

You are given the task of designing an aerobic, mixotrophic protist that can perform photosynthesis in fairly deep water (e.g., 250 m deep), and can also crawl about and engulf small particles. With which two of these structures would you provide your protist?
1. hydrogenosome
2. apicoplast
3. pseudopods
4. chloroplast from red alga
5. chloroplast from green alga
A) 1 and 2
B) 2 and 3
C) 2and4
D) 3 and 4
E) 4 and 5

D) 3 and 4

126

You are given the task of designing an aquatic protist that is a primary producer. It cannot swim on its own, yet must stay in well-lit surface waters. It must be resistant to physical damage from wave action. It should be most similar to a(n)
A) diatom.
B) dinoflagellate.
C) apicomplexan.
D) red alga.
E) radiolarian.

A) diatom.

127

Some protists, formerly united as the ʺamitochondriateʺ clade, have recently been shown to be rather diverse. Some of them possess neither mitochondria nor mitochondrial genes (and have been classified as fungi). Others possess no mitochondria, but do have mitochondrial genes in their nuclear genome. Still others have modified mitochondria (viz. mitosomes or hydrogenosomes). Which statement(s) represent(s) consequences of these recent findings? 1. The amitochondriates do not comprise a true clade.
2. The ʺamitochondriate hypothesisʺ concerning the root of the eukaryotic tree has been strengthened.
3. Just as there is a diversity of cyanobacterial descendants among eukaryotes, so too is there a diversity of alpha-proteobacterial descendants among the eukaryotes.
4. If the amitochondriate organisms continued to be recognized as a taxon, this taxon would be polyphyletic.
5. Horizontal gene transfer involving mitochondrial genes has occurred in some amitochondriate organisms.
A) 1 only
B) 1 and 4
C) 2and3
D) 1, 3, and 5
E) all except 2

E) all except 2

128

Similar to most amoebozoans, the forams and the radiolarians also have pseudopods, as do the white blood cells of animals. If one were to erect a taxon that included all organisms that have cells with pseudpods, what would be true of such a taxon?
A) It would be polyphyletic.
B) It would be paraphyletic.
C) It would be monophyletic.
D) It would include all eukaryotes.

A) It would be polyphyletic.

129

You are designing an artificial drug-delivery ʺcellʺ that can penetrate animal cells. Which of these protist structures should provide the most likely avenue for research along these lines?
A) pseudopods
B) apical complex
C) excavated feeding grooves D) nucleomorphs
E) mitosomes

B) apical complex

130

A gelatinous seaweed that grows in shallow, cold water and undergoes heteromorphic alternation of generations is most probably what type of alga?
A) red
B) green
C) brown
D) yellow

C) brown

131

Plastids that are surrounded by more than two membranes are evidence of
A) evolution from mitochondria.
B) fusion of plastids.
C) origin of the plastids from archaea.
D) secondary endosymbiosis.
E) budding of the plastids from the nuclear envelope.

D) secondary endosymbiosis.

132

Biologists suspect that endosymbiosis gave rise to mitochondria before plastids partly because
A) the products of photosynthesis could not be metabolized without mitochondrial enzymes.
B) all eukaryotes have mitochondria (or their remnants), whereas many eukaryotes do not have plastids.
C) mitochondrial DNA is less similar to prokaryotic DNA than is plastid DNA.
D) without mitochondrial CO2 production, photosynthesis could not occur.
E) mitochondrial proteins are synthesized on cytosolic ribosomes, whereas plastids utilize their own ribosomes.

B) all eukaryotes have mitochondria (or their remnants), whereas many eukaryotes do not have plastids.

133

Which group is incorrectly paired with its description?
A) rhizarians–morphologically diverse group defined by DNA similarities
B) diatoms–important producers in aquatic communities
C) red algae–acquired plastids by secondary endosymbiosis D) apicomplexans–parasites with intricate life cycles
E) diplomonads–protists with modified mitochondria

C) red algae–acquired plastids by secondary endosymbiosis

134

Which protists are in the same eukaryotic ʺsupergroupʺ as land plants?
A) green algae
B) dinoflagellates
C) red algae
D) brown algae
E) A and C are both correct

E) A and C are both correct

135

In life cycles with an alternation of generations, multicellular haploid forms alternate with
A) unicellular haploid forms.
B) unicellular diploid forms.
C) multicellular haploid forms. D) multicellular diploid forms.
E) multicellular polyploid forms.

D) multicellular diploid forms.

136

Which of the following do all fungi have in common?
A) meiosis in basidia
B) coenocytic hyphae
C) sexual life cycle
D) absorption of nutrients
E) symbioses with algae

D) absorption of nutrients

137

The hydrolytic digestion of which of the following should produce monomers that are aminated (i.e., have an amine group attached) molecules of beta-glucose?
A) insect exoskeleton
B) plant cell walls
C) fungal cell walls
D) A and C only
E) A, B and C

D) A and C only

138

If all fungi in an environment that perform decomposition were to suddenly die, then which group of organisms should benefit most, due to the fact that their fungal competitors have been removed?
A) plants
B) protists
C) prokaryotes
D) animals
E) mutualistic fungi

C) prokaryotes

139

When a mycelium infiltrates an unexploited source of dead organic matter, what are most likely to appear within the food source soon thereafter?
A) fungal haustoria
B) soredia
C) fungal enzymes
D) increased oxygen levels
E) larger bacterial populations

C) fungal enzymes

140

Which of the following is a characteristic of hyphate fungi (fungi featuring hyphae)? A) They acquire their nutrients by phagocytosis.
B) Their body plan is a unicellular sphere.
C) Their cell walls consist mainly of cellulose microfibrils.
D) They are adapted for rapid directional growth to new food sources.
E) They reproduce asexually by a process known as budding.

D) They are adapted for rapid directional growth to new food sources.

141

The functional significance of porous septa in certain fungal hyphae is most similar to that represented by which pair of structures in animal cells and plant cells, respectively?
A) desmosomes : tonoplasts
B) gap junctions : plasmodesmata
C) tight junctions : plastids
D) centrioles : plastids
E) flagella : central vacuoles

B) gap junctions : plasmodesmata

142

What is the primary role of a mushroomʹs underground mycelium?
A) absorbing nutrients
B) anchoring
C) sexual reproduction
D) asexual reproduction
E) protection

A) absorbing nutrients

143

What do fungi and arthropods have in common?
A) Both groups are commonly coenocytic.
B) The haploid state is dominant in both groups.
C) Both groups are predominantly heterotrophs that ingest their food.
D) The protective coats of both groups are made of chitin.
E) Both groups have cell walls.

D) The protective coats of both groups are made of chitin.

144

In septate fungi, what structures allow cytoplasmic streaming to distribute needed nutrients, synthesized compounds, and organelles throughout the hyphae?
A) multiple chitinous layers in cross walls
B) pores in cross walls
C) complex micro tubular cytoskeletons
D) two nuclei
E) tight junctions that form in cross walls between cells

B) pores in cross walls

145

What accounts most directly for the extremely fast growth of a fungal mycelium?
A) rapid distribution of synthesized proteins by cytoplasmic streaming
B) a long tubular body shape
C) the readily available nutrients from their ingestive mode of nutrition
D) a dikaryotic condition that supplies greater amounts of proteins and nutrients

A) rapid distribution of synthesized proteins by cytoplasmic streaming

146

The vegetative (nutritionally active) bodies of most fungi are
A) composed of hyphae.
B) referred to as a mycelium. C) usually underground.
D) A and B only
E) A, B, and C

E) A, B, and C

147

Both fungus-farming ants and their fungi can synthesize the same structural polysaccharide from the beta-glucose. What is this polysaccharide?
A) amylopectin
B) chitin
C) cellulose
D) lignin
E) glycogen

B) chitin

148

Consider two hyphae having equal dimensions: one from a septate species and the other from a coenocytic species. Compared with the septate species, the coenocytic species should have
A) fewer nuclei.
B) more pores.
C) less chitin.
D) less cytoplasm.
E) reduced cytoplasmic streaming.

C) less chitin.

149

Which of the following terms is correctly associated with fungi in general?
A) sporophytes
B) make only sexually produced spores
C) ecologically important
D) polyphyletic
E) ingestive nutrition

C) ecologically important

150

Which of the following vary tremendously from each other in morphology and belong to several fungal phyla?
A) lichens
B) ascomycetes
C) club fungi
D) arbuscular mycorrhizae
E) ergot fungi

A) lichens

151

In most fungi, karyogamy does not immediately follow plasmogamy, which consequently
A) means that sexual reproduction can occur in specialized structures.
B) results in multiple diploid nuclei per cell.
C) allows fungi to reproduce asexually most of the time.
D) results in heterokaryotic or dikaryotic cells.
E) is strong support for the claim that fungi are not truly eukaryotic.

D) results in heterokaryotic or dikaryotic cells.

152

Which process occurs in fungi and has the opposite effect on a cellʹs chromosome number than does meiosis I?
A) mitosis
B) plasmogamy
C) crossing-over
D) binary fission
E) karyogamy

E) karyogamy

153

Fungal cells can reproduce asexually by undergoing mitosis followed by cytokinesis. Many fungi can also prepare to reproduce sexually by undergoing
A) cytokinesis followed by karyokinesis.
B) binary fission followed by cytokinesis.
C) plasmolysis followed by karyotyping.
D) plasmogamy followed by karyogamy.
E) sporogenesis followed by gametogenesis.

D) plasmogamy followed by karyogamy.

154

Which of the following statements is true of deuteromycetes?
A) They are the second of five fungal phyla to have evolved.
B) They represent the phylum in which all the fungal components of lichens are classified.
C) They are the group of fungi that have, at present, no known sexual stage.
D) They are the group that includes molds, yeasts, and lichens.
E) They include the imperfect fungi that lack hyphae.

C) They are the group of fungi that have, at present, no known sexual stage.

155

For mycelia described as heterokaryons or as being dikaryotic, which process has already occurred, and which process has not yet occurred?
A) germination, plasmogamy B) karyogamy, germination
C) meiosis, mitosis
D) germination, mitosis
E) plasmogamy, genetic recombination

E) plasmogamy, genetic recombination

156

A chemical secreted by a female Bombyx moth helps the male of the species locate her, at which time sexual reproduction may occur. This chemical is most similar in function to which chemicals used by sexually reproducing fungi?
A) chitin
B) enzymes
C) lysergic acids
D) aflatoxins
E) pheromones

E) pheromones

157

Which of the following is characterized by the lack of an observed sexual phase in its membersʹ life cycle?
A) Glomeromycota
B) Basidiomycota
C) Chytridiomycota
D) Deuteromycota
E) Zygomycota

D) Deuteromycota

158

A biologist is trying to classify a newly discovered fungus on the basis of the following characteristics: filamentous appearance, reproduction by asexual spores, no apparent sexual phase, and parasitism of woody plants. If asked for advice, to which group would you assign this new species?
A) Deuteromycota
B) Zygomycota
C) Ascomycota
D) Basidiomycota
E) Glomeromycota

A) Deuteromycota

159

Which of these structures are most likely to be a component of both chytrid zoospores and motile animal cells?
A) cilia
B) flagella
C) pseudopods
D) heterokaryons
E) haustoria

B) flagella

160

Fossil fungi date back to the origin and early evolution of plants. What combination of environmental and morphological change is similar in the evolution of both fungi and plants?
A) presence of ʺcoal forestsʺ and change in mode of nutrition
B) periods of drought and presence of filamentous body shape
C) predominance in swamps and presence of cellulose in cell walls
D) colonization of land and loss of flagellated cells
E) continental drift and mode of spore dispersal

D) colonization of land and loss of flagellated cells

161

Which of the following characteristics is shared by both chytrids and other kinds of fungi?
A) presence of flagella
B) zoospores
C) autotrophic mode of nutrition
D) cell walls of cellulose
E) nucleotide sequences of several genes

E) nucleotide sequences of several genes

162

The multicellular condition of animals and fungi seems to have arisen
A) due to common ancestry.
B) by convergent evolution.
C) by inheritance of acquired traits.
D) by natural means, and is a homology.
E) by serial endosymbioses.

B) by convergent evolution.

163

Asexual reproduction in yeasts occurs by budding. Due to unequal cytokinesis, the ʺbudʺ cell receives less cytoplasm than the parent cell. Which of the following should be true of the smaller cell until it reaches the size of the larger cell?
A) It should produce fewer fermentation products per unit time.
B) It should produce ribosomal RNA at a slower rate.
C) It should be transcriptionally less active.
D) It should have reduced motility.
E) It should have a smaller nucleus.

A) It should produce fewer fermentation products per unit time.

164

This phylum contains organisms that most closely resemble the common ancestor of fungi and animals:
A) Zygomycota
B) Ascomycota
C) Basidiomycota
D) Glomeromycota
E) Chytridiomycota

E) Chytridiomycota

165

This phylum formerly included the members of the new phylum Glomeromycota:
A) Zygomycota
B) Ascomycota
C) Basidiomycota
D) Glomeromycota
E) Chytridiomycota

A) Zygomycota

166

Members of this phylum produce two kinds of haploid spores, one kind being asexually produced conidia:
A) Zygomycota
B) Ascomycota
C) Basidiomycota
D) Glomeromycota
E) Chytridiomycota

B) Ascomycota

167

This phylum contains the mushrooms, shelf fungi, and puffballs: A) Zygomycota
B) Ascomycota
C) Basidiomycota
D) Glomeromycota
E) Chytridiomycota

C) Basidiomycota

168

Members of this phylum form arbuscular mycorrhizae:
A) Zygomycota
B) Ascomycota
C) Basidiomycota
D) Glomeromycota
E) Chytridiomycota

D) Glomeromycota

169

You have been given the assignment of locating living members of the phylum Glomeromycota. Where is the best place to look for these fungi?
A) between the toes of a person with ʺathleteʹs footʺ
B) in stagnant freshwater ponds
C) the roots of vascular plants
D) growing on rocks and tree bark
E) the kidneys of mammals

C) the roots of vascular plants

170

Zygosporangia are to zygomycetes as basidia are to A) basal fungi.
B) chytrids.
C) sac fungi.
D) basidiospores.
E) club fungi.

E) club fungi.

171

What are the sporangia of the bread mold Rhizopus?
A) asexual structures that produce haploid spores
B) asexual structures that produce diploid spores
C) sexual structures that produce haploid spores
D) sexual structures that produce diploid spores
E) vegetative structures with no role in reproduction

A) asexual structures that produce haploid spores

172

The gray-black, filamentous, haploid mycelium growing on bread is most likely what kind of organism?
A) chytrid
B) ascomycete
C) basidiomycete
D) deuteromycete
E) zygomycete

E) zygomycete

173

The ascomycetes get their name from which aspect of their life cycle?
A) vegetative growth form
B) asexual spore production C) sexual structures
D) shape of the spore
E) type of vegetative mycelium

C) sexual structures

174

Which of these paired fungal structures are structurally and functionally most alike?
A) conidia and basidiocarps
B) sporangia and hyphae
C) soredia and gills
D) haustoria and arbuscules
E) zoospores and mycelia

D) haustoria and arbuscules

175

You are given an organism to identify. It has a fruiting body that contains many structures with eight haploid spores lined up in a row. What kind of a fungus is this?
A) zygomycete
B) ascomycete
C) deuteromycete
D) chytrid
E) basidiomycete

B) ascomycete

176

Which has the least affiliation with all of the others?
A) Glomeromycota
B) mycorrhizae
C) lichens
D) arbuscules
E) mutualistic fungi

C) lichens

177

Which of these is a fungal structure that is usually associated with asexual reproduction?
A) zygosporangium
B) basidium
C) conidiophore
D) ascus
E) antheridium

C) conidiophore

178

Arrange the following from largest to smallest: 1. ascospore
2. ascocarp
3. ascomycete 4. ascus
A) 3 → 4 → 2 → 1
B) 3 → 2 → 4 → 1
C) 3 → 4 → 1 → 2
D) 2 → 3 → 4 → 1
E) 2 → 4 → 1 → 3

B) 3 → 2 → 4 → 1

179

In which phylum are mushrooms and toadstools classified?
A) Basidiomycota
B) Ascomycota
C) Deuteromycota
D) Zygomycota
E) Chytridiomycota

A) Basidiomycota

180

Arrange the following from largest to smallest, assuming that they all come from the same fungus.
1. basidiocarp 2. basidium
3. basidiospore 4. mycelium
5. gill
A) 4, 5, 1, 2, 3
B) 5, 1, 4, 2, 3
C) 5,1,4,3,2
D) 5, 1, 3, 2, 4
E) 4, 1, 5, 2, 3

E) 4, 1, 5, 2, 3

181

Mushrooms with gills have meiotically produced spores located in or on
A) asci.
B) conidiophores.
C) basidia.
D) soredia.
E) zygosporangia.

C) basidia.

182

Among sac fungi, which of these correctly distinguishes ascospores from conidia?
A) ascospores are diploid, conidia are haploid
B) ascospores are produced only by meiosis, conidia are produced only by mitosis
C) ascospores have undergone genetic recombination during their production, conidia
have not
D) ascospores are larger, conidia are smaller
E) ascospores will germinate into haploid hyphae, conidia will germinate into diploid hyphae

C) ascospores have undergone genetic recombination during their production, conidia
have not

183

A fungal spore germinates, giving rise to a mycelium that grows outward into the soil surrounding the site where the spore originally landed. Which of these accounts for the fungal movement, as described here?
A) karyogamy
B) mycelial flagella
C) alternation of generations D) breezes distributing spores
E) cytoplasmic streaming in hyphae

E) cytoplasmic streaming in hyphae

184

In what structures do both Penicillium and Aspergillus produce asexual spores?
A) asci
B) zygosporangia
C) rhizoids
D) gametangia
E) conidiophores

E) conidiophores

185

Chemicals, secreted by soil fungi, that inhibit the growth of bacteria, are known as
A) antibodies.
B) aflatoxins.
C) hallucinogens.
D) antigens.
E) antibiotics.

E) antibiotics.

186

Lichens are symbiotic associations of fungi and
A) mosses.
B) cyanobacteria.
C) green algae.
D) either A or B
E) either B or C

E) either B or C

187

Lichens sometimes reproduce asexually using
A) coenocytic fungal hyphae located within photosynthetic cells.
B) the fruiting bodies of fungi.
C) flagellated, conjoined spores of both the fungus and alga.
D) specialized conidiophores.
E) small clusters of fungal hyphae surrounding photosynthetic cells.

E) small clusters of fungal hyphae surrounding photosynthetic cells.

188

In both lichens and mycorrhizae, what does the fungal partner provide to its photosynthetic partner?
A) carbohydrates
B) fixed nitrogen
C) antibiotics
D) water and minerals
E) protection from harmful UV

D) water and minerals

189

The symbiotic associations involving roots and soil fungi are considered
A) parasitic.
B) mutualistic.
C) commensal.
D) harmful to the plant partner.
E) the beginning stages of the formation of soil.

B) mutualistic.

190

If all mycorrhizae were somehow disrupted, then which of the following would be true?
A) There would be fewer infectious diseases.
B) We wouldnʹt have any antibiotics.
C) There would be no mushrooms for pizza.
D) Most vascular plants would be stunted in their growth.
E) Cheeses like blue cheese or Roquefort would not exist.

D) Most vascular plants would be stunted in their growth.

191

Which of the following best describes the physical relationship of the partners involved in lichens?
A) Fungal cells are enclosed within algal cells.
B) Lichen cells are enclosed within fungal cells.
C) Photosynthetic cells are surrounded by fungal hyphae.
D) The fungi grow on rocks and trees and are covered by algae.
E) Algal cells and fungal cells mix together without any apparent structure.

C) Photosynthetic cells are surrounded by fungal hyphae.

192

If haustoria from the fungal partner were to appear within the photosynthetic partner of a lichen, and if the growth rate of the photosynthetic partner consequently slowed substantially, then this would support the claim that
A) algae and cyanobacteria are autotrophic.
B) lichens are not purely mutualistic relationships.
C) algae require maximal contact with the fungal partner in order to grow at optimal rates.
D) fungi get all of the nutrition they need via the ʺleakinessʺ of photosynthetic partners.
E) soredia are asexual reproductive structures combining both the fungal and
photosynthetic partners.

B) lichens are not purely mutualistic relationships.

193

How are the vascular plants that are involved in mycorrhizae and the photosynthetic cells that are involved in lichens alike?
A) They provide organic nutrients to fungal partners.
B) They secrete acids that keep the fungal partner from growing too quickly.
C) They are in intimate associations with chytrids.
D) They are digested by fungal enzymes while still alive.
E) They contain endosymbiotic fungi.

A) They provide organic nutrients to fungal partners.

194

When pathogenic fungi are found growing on the roots of grape vines, grape farmers sometimes respond by covering the ground around their vines with plastic sheeting and pumping a gaseous fungicide into the soil. The most important concern of grape farmers who engage in this practice should be that the
A) fungicide might also kill the native yeasts residing on the surfaces of the grapes.
B) fungicide isnʹt also harmful to insect pests.
C) lichens growing on the vinesʹ branches are not harmed.
D) fungicide might also kill mycorrhizae.
E) sheeting is transparent so that photosynthesis can continue.

D) fungicide might also kill mycorrhizae.

195

Which term below refers to symbiotic relationships that involve fungi living between the cells in plant leaves?
A) pathogens
B) endosymbioses
C) endophytes
D) lichens
E) mycorrhizae

C) endophytes

196

If Penicillium typically secretes penicillin without disturbing the lichen relationship in which it is engaged, then what must have been true about its partner?
A) It should have lacked peptidoglycan in its cell wall. B) It was probably a red alga.
C) It was probably a member of the domain Bacteria.
D) It was probably a heterotrophic prokaryote.
E) It was probably infected by bacteriophage.

A) It should have lacked peptidoglycan in its cell wall.

197

Sexual reproduction has never been observed among the fungi that produce the blue-green marbling of blue cheeses. What is true of these fungi and others that do not have a sexual stage?
A) They are currently classified among the deuteromycetes.
B) They do not form heterokaryons.
C) Their spores are produced by mitosis.
D) Only A and B are correct.
E) A, B, and C are correct.

E) A, B, and C are correct.

198

Both fungus-derived antibiotics and hallucinogens used by humans probably evolved in fungi as a means to
A) reduce competition for nutrients.
B) help humanity survive.
C) promote their ingestion of foodstuffs.
D) eliminate other fungi.
E) discourage animal predators.

A) reduce competition for nutrients.

199

A billionaire buys a sterile volcanic island that recently emerged from the sea. To speed the arrival of conditions necessary for plant growth, the billionaire might be advised to aerially sow what over the island?
A) basiodiospores
B) spores of ectomycorrhizae
C) soredia
D) yeasts
E) leaves (as food for fungus-farming ants)

C) soredia

200

Mycorrhizae are to the roots of vascular plants as endophytes are to vascular plantsʹ
A) leaf mesophyll.
B) stem apical meristems.
C) root apical merisems
D) xylem.
E) waxy cuticle.

A) leaf mesophyll.

201

Which of the following conditions is caused by a fungus that is accidentally consumed along with rye flour?
A) ergotism
B) athleteʹs foot
C) ringworm
D) candidiasis (Candida yeast infection)
E) coccidioidomycosis

A) ergotism

202

Orchid seeds are tiny, with virtually no endosperm and with miniscule cotyledons. If such seeds are deposited in a dark, moist environment then which of these represents the most likely means by which fungi might assist in seed germination, given what the seeds lack?
A) by transferring some chloroplasts to the embryo in each seed
B) by providing the seeds with water and minerals
C) by providing the embryos with some of the organic nutrients they have absorbed D) by strengthening the seed coat that surrounds each seed

C) by providing the embryos with some of the organic

203

All fungi share which of the following characteristics?
A) symbiotic
B) heterotrophic
C) flagellated
D) pathogenic
E) act as decomposers

B) heterotrophic

204

Which feature seen in chytrids supports the hypothesis that they diverged earliest in fungal evolution?
A) the absence of chitin within the cell wall
B) coenocytic hyphae
C) flagellated spores
D) formation of resistant zygosporangia
E) parasitic lifestyle

C) flagellated spores

205

Which of the following cells or structures are associated with asexual reproduction in fungi?
A) ascospores
B) basidiospores
C) zygosporangia
D) conidiophores
E) ascocarps

D) conidiophores

206

The adaptive advantage associated with the filamentous nature of fungal mycelia is primarily related to
A) the ability to form haustoria and parasitize other organisms.
B) avoiding sexual reproduction until the environment changes.
C) the potential to inhabit almost all terrestrial habitats.
D) the increased probability of contact between different mating types.
E) an extensive surface area well suited for invasive growth and absorptive nutrition.

E) an extensive surface area well suited for invasive growth and absorptive nutrition.

207

The photosynthetic symbiont of a lichen is often a(n)
A) moss.
B) green alga.
C) brown alga.
D) ascomycete.
E) small vascular plant.

B) green alga.

208

Among the organisms listed here, which are thought to be the closest relatives of fungi? A) animals
B) vascular plants
C) mosses
D) brown algae
E) slime molds

A) animals