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Chapter 26 & 17

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Traditionally, whales and hippopotamuses have been classified in different orders, the Cetacea and the Artiodactyla, respectively. Recent molecular evidence, however, indicates that the whales' closest living relatives are the hippos. This has caused some zoologists to lump the two orders together into a single clade, the Cetartiodactyla. There is no consensus on whether the Cetartiodactyla should be accorded order status or superorder status. This is because it remains unclear whether the whale lineage diverged from the lineage leading to the hippos before or after the other members of the order Artiodactyla (pigs, camels, etc.) diverged (see Figure 26.2). Figure 26.2 contrasts the "Within the artiodactyls" origin of the whale lineage with the "Without the artiodactyls" origin of the whale lineage 48) What can be properly inferred from Figure 26.2? A) In the "Without" tree, pigs are more distantly related to hippos than is depicted in the "Within" tree. B) In the "Without" tree, pigs are more closely related to hippos than are whales. C) In the "Within" tree, pigs are more closely related to whales than they are to hippos. D) The "Without" tree is more consistent with molecular evidence than is the "Within" tree. E) In the "Within" tree, all artiodactyls, including hippos, are more closely related to each other than any are to the whales.

14) Which of the following is an important source of endotoxin in gram-negative species? A) endospore B) sex pilus C) flagellum D) cell wall E) capsule

40) Which extinct species should be the best candidate to serve as the outgroup for the clade whose common ancestor occurs at position 2 in Figure 26.1? A) A B) B C) C D) D E) E

7) The term homoplasy is most applicable to which of the following features? A) the legless condition found in various lineages of extant lizards B) the five-digit condition of human hands and bat wings C) the β hemoglobin genes of mice and of humans D) the fur that covers Australian moles and North American moles E) the bones of bat forelimbs and the bones of bird forelimbs

78) Plantlike photosynthesis that releases O₂ occurs in A) cyanobacteria. B) chlamydias. C) archaea. D) actinomycetes. E) chemoautotrophic bacteria.

13) Prokaryotes' essential genetic information is located in the A) nucleolus. B) nucleoid. C) nucleosome. D) plasmids. E) exospore.

77) Bacteria perform each of the following ecological roles. Which role typically does not involve a symbiosis? A) skin commensalist B) decomposer C) aggregates with methane-consuming archaea D) gut mutualist E) pathogen

8) If, someday, an archaean cell is discovered whose rRNA sequence is more similar to that of humans than the sequence of mouse rRNA is to that of humans, the best explanation for this apparent discrepancy would be A) homology. B) homoplasy. C) common ancestry. D) retro-evolution by humans. E) coevolution of humans and that archaean.

34) What important criterion was used in the late 1960s to distinguish between the three multicellular eukaryotic kingdoms of the five-kingdom classification system? A) the number of cells present in individual organisms B) the geological stratum in which fossils first appear C) the nutritional modes they employ D) the biogeographic province where each first appears E) the features of their embryos

73) If you were using cladistics to build a phylogenetic tree of cats, which of the following would be the best outgroup? A) lion B) domestic cat C) wolf D) leopard E) tiger

The following table depicts characteristics of five prokaryotic species (A—E). Use the information in the table to answer the following question. 63) Which two species should have much more phospholipid, in the form of bilayers, in their cytoplasms than most other bacteria? A) species A and B B) species A and C C) species B and E D) species C and D E) species C and E

30) Which of the following traits do archaeans and bacteria share? 1. composition of the cell wall 2. presence of plasma membrane 3. lack of a nuclear envelope 4. identical rRNA sequences A) 1 only B) 3 only C) 1 and 3 D) 2 and 3 E) 2 and 4

37) Which eukaryotic kingdom is polyphyletic, and therefore unacceptable, based on cladistics? A) Plantae B) Fungi C) Animalia D) Protista E) Monera

76) Which of the following involves metabolic cooperation among prokaryotic cells? A) binary fission B) endospore formation C) endotoxin release D) biofilms E) photoautotrophy

Figure 26.5. Humans, chimpanzees, gorillas, and orangutans are members of a clade called the great apes, which shared a common ancestor about 18 million years ago (Figure 26.4). Gibbons and siamangs comprise a clade called the lesser apes. Tree-branch lengths indicate elapsed time. 54) The great apes comprise the family Hominidae, whereas the lesser apes comprise the family Hylobatidae. If the extant organisms on the far right side of Figure 26.5 comprise the next-most exclusive (i.e., specific) taxon, then they comprise different A) subspecies. B) species. C) genuses. D) genera. E) orders.

The following table depicts characteristics of five prokaryotic species (A—E). Use the information in the table to answer the following question. 68) Which species might be able to include Hfr cells? A) species A B) species B C) species C D) species D E) species E

10) Which of the following pairs are the best examples of homologous structures? A) bones in the bat wing and bones in the human forelimb B) owl wing and hornet wing C) bat wing and bird wing D) eyelessness in the Australian mole and eyelessness in the North American mole

11) If a bacterium regenerates from an endospore that did not possess any of the plasmids that were contained in its original parent cell, the regenerated bacterium will probably also A) lack antibiotic-resistant genes. B) lack a cell wall. C) lack a chromosome. D) lack water in its cytoplasm. E) be unable to survive in its normal environment.

20) Concerning growth in genome size over evolutionary time, which of these is least associated with the others? A) orthologous genes B) gene duplications C) paralogous genes D) gene families

21) Hershey and Chase performed an elegant experiment that convinced most biologists that DNA, rather than protein, was the genetic material. This experiment subjected bacteria to the same gene transfer mechanism as occurs in A) transduction. B) transformation. C) conjugation. D) binary fission. E) endosymbiosis.

23) Which kind of DNA should provide the best molecular clock for determining the evolutionary relatedness of several species whose common ancestor became extinct billions of years ago? A) that coding for ribosomal RNA B) intronic DNA belonging to a gene whose product performs a crucial function C) paralogous DNA that has lost its function (i.e., no longer codes for functional gene product) D) mitochondrial DNA E) exonic DNA that codes for a noncrucial part of a polypeptide

28) Which statement about the domain Archaea is true? A) Genetic prospecting has recently revealed the existence of many previously unknown archaean species. B) No archaeans can reduce CO₂ to methane. C) The genomes of archaeans are unique, containing no genes that originated within bacteria. D) No archaeans can inhabit solutions that are nearly 30% salt. E) No archaeans are adapted to waters with temperatures above the boiling point.

31) Assuming that each of these possesses a cell wall, which prokaryotes should be expected to be most strongly resistant to plasmolysis in hypertonic environments? A) extreme halophiles B) extreme thermophiles C) methanogens D) cyanobacteria E) nitrogen-fixing bacteria that live in root nodules

33) What kind of evidence has recently made it necessary to assign the prokaryotes to either of two different domains, rather than assigning all prokaryotes to the same kingdom? A) molecular B) behavioral C) nutritional D) anatomical E) ecological

38) Which eukaryotic kingdom includes members that are the result of endosymbioses that included an ancient proteobacterium and an ancient cyanobacterium? A) Plantae B) Fungi C) Animalia D) Protista E) Monera

5) Jams, jellies, preserves, honey, and other foodstuffs with high sugar content hardly ever become contaminated by bacteria, even when the food containers are left open at room temperature. This is because bacteria that encounter such an environment A) undergo death by plasmolysis. B) are unable to metabolize the glucose or fructose, and thus starve to death. C) experience lysis. D) are obligate anaerobes. E) are unable to swim through these thick and viscous materials.

51) The data were collected from the heterocysts of a nitrogen-fixing cyanobacterium inhabiting equatorial ponds. Study the following graph and choose the most likely explanation for the shape of the curve. A) Enough O₂ enters heterocysts during hours of peak photosynthesis to have a somewhat-inhibitory effect on nitrogen fixation. B) Light-dependent reaction rates must be highest between 1800 hours and 0600 hours. C) Atmospheric N₂ levels increase at night because plants are no longer metabolizing this gas, so they are not absorbing this gas through their stomata. D) Heterocyst walls become less permeable to N₂ influx during darkness. E) The amount of fixed nitrogen that is dissolved in the pond water in which the cyanobacteria are growing peaks at the close of the photosynthetic day (1800 hours).

52) Consider the thermoacidophile, Sulfolobus acidocaldarius. Which of the following graphs most accurately depicts the expected temperature and pH profiles of its enzymes? (Note: The horizontal axes of these graphs are double, with pH above and temperature below.) A. SEE IMAGE B. SEE IMAGE C. SEE IMAGE D. SEE IMAGE

70) In a comparison of birds and mammals, having four limbs is A) a shared ancestral character. B) a shared derived character. C) a character useful for distinguishing birds from mammals. D) an example of analogy rather than homology. E) a character useful for sorting bird species.

74) Photoautotrophs use A) light as an energy source and CO₂ as a carbon source. B) light as an energy source and methane as a carbon source. C) N₂ as an energy source and CO₂ as a carbon source. D) CO₂ as both an energy source and a carbon source. E) H₂S as an energy source and CO₂ as a carbon source.

9) Prokaryotic ribosomes differ from those present in eukaryotic cytosol. Because of this, which of the following is correct? A) Some antibiotics can block protein synthesis in bacteria without effects in the eukaryotic host. B) Eukaryotes did not evolve from prokaryotes. C) Translation can occur at the same time as transcription in eukaryotes but not in prokaryotes. D) Some antibiotics can block the synthesis of peptidoglycan in the walls of bacteria. E) Prokaryotes are able to use a much greater variety of molecules as food sources than can eukaryotes.

Figure 27.2 depicts changes to the amount of DNA present in a recipient cell that is engaged in conjugation with an Hfr cell. Hfr cell DNA begins entering the recipient cell at Time A. Assume that reciprocal crossing over occurs (in other words, a fragment of the recipient's chromosome is exchanged for a homologous fragment from the Hfr cell's DNA). Use Figure 27.2 to answer the following question. Figure 27.2 50) Which question, arising from the results depicted in Figure 27.2, is most interesting from a genetic perspective, and has the greatest potential to increase our knowledge base? A) If reciprocal crossing over could occur even if the piece of donated Hfr DNA is identical to the homologous portion of the recipient's chromosome, what prevents this from occurring? B) What forces are generally responsible for disrupting the sex pilus? C) How is it that a recipient cell does not necessarily become an Hfr cell as the result of conjugation with an Hfr cell? D) What makes a cell an Hfr cell?

The following table depicts characteristics of five prokaryotic species (A—E). Use the information in the table to answer the following question. 66) Gram-variable prokaryotes are, sometimes, those without any peptidoglycan. Which two species are most likely to be archaeans? A) species A and B B) species A and C C) species B and E D) species C and D E) species C and E

The following table depicts characteristics of five prokaryotic species (A—E). Use the information in the table to answer the following question. 70) Which two species might be expected to cooperate metabolically, perhaps forming a biofilm wherein one species surrounds cells of the other species? A) species A and B B) species A and C C) species B and E D) species C and D E) species C and E

Traditionally, whales and hippopotamuses have been classified in different orders, the Cetacea and the Artiodactyla, respectively. Recent molecular evidence, however, indicates that the whales' closest living relatives are the hippos. This has caused some zoologists to lump the two orders together into a single clade, the Cetartiodactyla. There is no consensus on whether the Cetartiodactyla should be accorded order status or superorder status. This is because it remains unclear whether the whale lineage diverged from the lineage leading to the hippos before or after the other members of the order Artiodactyla (pigs, camels, etc.) diverged (see Figure 26.2). Figure 26.2 contrasts the "Within the artiodactyls" origin of the whale lineage with the "Without the artiodactyls" origin of the whale lineage 44) If it turns out that the whale lineage diverged from the lineage leading to hippos after the divergence of the lineage leading to the pigs and other artiodactyls, and if the whales continue to be classified in the order Cetacea, then what becomes true of the taxon Cetartiodactyla? A) It should be considered as one monophyletic order. B) It should be considered a superorder that consists of two monophyletic orders. C) It should be established as a paraphyletic order. D) It should be thrown out or modified by taxonomists if classification is to reflect evolutionary history.

Traditionally, whales and hippopotamuses have been classified in different orders, the Cetacea and the Artiodactyla, respectively. Recent molecular evidence, however, indicates that the whales' closest living relatives are the hippos. This has caused some zoologists to lump the two orders together into a single clade, the Cetartiodactyla. There is no consensus on whether the Cetartiodactyla should be accorded order status or superorder status. This is because it remains unclear whether the whale lineage diverged from the lineage leading to the hippos before or after the other members of the order Artiodactyla (pigs, camels, etc.) diverged (see Figure 26.2). Figure 26.2 contrasts the "Within the artiodactyls" origin of the whale lineage with the "Without the artiodactyls" origin of the whale lineage 46) If cetaceans are determined to have diverged from the lineage leading to the artiodactyls before the divergence of lineages leading to the modern artiodactyls (including hippos), then the cetaceans can be considered 1. a sister order to the order Artiodactyla. 2. an ingroup of the order Artiodactyla. 3. the common ancestor of the order Artiodactyla. A) 1 only B) 3 only C) 1 and 2 D) 1 and 3 E) 2 and 3

Traditionally, zoologists have placed birds in their own class, Aves. More recently, molecular evidence has shown that birds are more closely related to reptiles than their anatomy reveals. Genetically, birds are more closely related to crocodiles than crocodiles are to turtles. Thus, bird anatomy has become highly modified as they have adapted to flight, without their genes having undergone nearly as much change. 64) For a proponent of PhyloCode classification, what is true of the reptile clade if birds are not included in it? A) It becomes paraphyletic and, thus, an invalid reflection of evolutionary history. B) It becomes a subclass, instead of a class. C) It becomes a superclass, whereas the birds remain a class. D) PhyloCode does not concern itself with what is, or is not, a clade.

1) Mycoplasmas are bacteria that lack cell walls. On the basis of this structural feature, which statement concerning mycoplasmas should be true? A) They are gram-negative. B) They are subject to lysis in hypotonic conditions. C) They lack a cell membrane as well. D) They should contain less cellulose than do bacteria that possess cell walls. E) They possess typical prokaryotic flagella.

13) Which mutation should least require realignment of homologous regions of a gene that is common to several related species? A) three-base insertion B) one-base substitution C) four-base insertion D) one-base deletion E) three-base deletion

16) In a hypothetical situation, the genes for sex pilus construction and for tetracycline resistance are located together on the same plasmid within a particular bacterium. If this bacterium readily performs conjugation involving a copy of this plasmid, then the result should be A) a bacterium that has undergone transduction. B) the rapid spread of tetracycline resistance to other bacteria in that habitat. C) the subsequent loss of tetracycline resistance from this bacterium. D) the production of endospores among the bacterium's progeny. E) the temporary possession by this bacterium of a completely diploid genome.

2) The various taxonomic levels (namely, genera, classes, etc.) of the hierarchical classification system differ from each other on the basis of A) how widely the organisms assigned to each are distributed throughout the environment. B) their inclusiveness. C) the relative genome sizes of the organisms assigned to each. D) morphological characters that are applicable to all organisms.

2) Though plants, fungi, and prokaryotes all have cell walls, we place them in different taxa. Which of these observations comes closest to explaining the basis for placing these organisms in different taxa, well before relevant data from molecular systematics became available? A) Some closely resemble animals, which lack cell walls. B) Their cell walls are composed of very different biochemicals. C) Some have cell walls only for support. D) Some have cell walls only for protection from herbivores. E) Some have cell walls only to control osmotic balance.

24) Match the numbered terms to the description that follows. Choose all appropriate terms. 1. autotroph 2. heterotroph 3. phototroph 4. chemotroph an organism that relies on photons to excite electrons within its membranes A) 1 only B) 3 only C) 1 and 3 D) 2 and 4 E) 1, 3, and 4

25) The lakes of northern Minnesota are home to many similar species of damselflies of the genus Enallagma that have apparently undergone speciation from ancestral stock since the last glacial retreat about 10,000 years ago. Sequencing which of the following would probably be most useful in sorting out evolutionary relationships among these closely related species? A) nuclear DNA B) mitochondrial DNA C) small nuclear RNA D) ribosomal RNA E) amino acids in proteins

35) In general, what is the primary ecological role of prokaryotes? A) parasitizing eukaryotes, thus causing diseases B) breaking down organic matter C) metabolizing materials in extreme environments D) adding methane to the atmosphere E) serving as primary producers in terrestrial environments

35) Members of which kingdom have cell walls and are all heterotrophic? A) Plantae B) Fungi C) Animalia D) Protista E) Monera

38) Foods can be preserved in many ways by slowing or preventing bacterial growth. Which of these methods should be least effective at inhibiting bacterial growth? A) Refrigeration: slows bacterial metabolism and growth. B) Closing previously opened containers: prevents more bacteria from entering, and excludes O₂. C) Pickling: creates a pH at which most bacterial enzymes cannot function. D) Canning in heavy sugar syrup: creates osmotic conditions that remove water from most bacterial cells. E) Irradiation: kills bacteria by mutating their DNA to such an extent that their DNA-repair enzymes are overwhelmed.

39) A large proportion of archaeans are extremophiles, so called because they inhabit extreme environments with high acidity, salinity, and/or temperature. Such environments are thought to have been much more common on the primitive Earth. Thus, modern extremophiles survive only in places that their ancestors became adapted to long ago. Which of the following is, consequently, a valid statement about modern extremophiles, assuming that their habitats have remained relatively unchanged? A) Among themselves, they should share relatively few ancestral traits, especially those that enabled ancestral forms to adapt to extreme conditions. B) On a phylogenetic tree whose branch lengths are proportional to the amount of genetic change, the branches of the extremophiles should be shorter than the non-extremophilic archaeans. C) They should contain genes that originated in eukaryotes that are the hosts for numerous species of bacteria. D) They should currently be undergoing a high level of horizontal gene transfer with non-extremophilic archaeans.

6) Which individual would make the worst systematist? One who is uncomfortable with the A) Linnaean system of classification. B) notion of hypothetical phylogenies. C) PhyloCode method of classification. D) notion of permanent polytomies.

7) Which two structures play direct roles in permitting bacteria to adhere to each other, or to other surfaces? 1. capsules 2. endospores 3. fimbriae 4. plasmids 5. flagella A) 1 and 2 B) 1 and 3 C) 2 and 3 D) 3 and 4 E) 3 and 5

Figure 26.3. Morphologically, species A is very similar to four other species, B—E. Yet the nucleotide sequence deep within an intron in a gene shared by all five of these eukaryotic species is quite different in species A compared to that of the other four species when we study the nucleotides present at each position. 49) If the sequence of species A in Figure 26.3 differs from that of the other four species due to simple misalignment, then what should the computer software find when it compares the sequence of species A to those of the other four species? A) The nucleotide at position 1 should be different in species A, but the same in species BE. B) The nucleotide sequence of species A should have long sequences that are nearly identical to those of the other species, but offset in terms of position number. C) The sequences of species BE, though different from that of species A, should be identical to each other, without exception. D) If the software compares the amino acid sequence of the actual protein product rather than the nucleotide sequence, then the amino acid sequences of species BE should be similar to each other, but very different from that of species A. E) Computer software is useless in determining sequences of introns; it can only be used with exons.

Figure 26.5. Humans, chimpanzees, gorillas, and orangutans are members of a clade called the great apes, which shared a common ancestor about 18 million years ago (Figure 26.4). Gibbons and siamangs comprise a clade called the lesser apes. Tree-branch lengths indicate elapsed time. 57) Assuming chimps and gorillas are humans' closest relatives, removing humans from the great ape clade and placing them in a different clade has the effect of making the phylogenetic tree of the great apes A) polyphyletic. B) paraphyletic. C) monophyletic. D) conform with Linnaeus' view of great ape phylogeny.

Figure 26.5. Humans, chimpanzees, gorillas, and orangutans are members of a clade called the great apes, which shared a common ancestor about 18 million years ago (Figure 26.4). Gibbons and siamangs comprise a clade called the lesser apes. Tree-branch lengths indicate elapsed time. 59) From Figure 26.5, what is true of Dryopithecus and Ouranopithecus? 1. They were great apes. 2. They shared a common ancestor more recently with the orangutans than with the other great apes. 3. They appear to be part of a polytomy. 4. Their closest common ancestor with all of the extant great apes is the one they share with the orangutans. 5. They were about as different from each other genetically as humans are different from chimps. A) 1, 2, and 4 B) 1, 3, and 4 C) 2, 4, and 5 D) 1, 2, 3, and 4 E) 2, 3, 4, and 5

Nitrogenase, the enzyme that catalyzes nitrogen fixation, is inhibited whenever free O₂ reaches a critical concentration. Consequently, nitrogen fixation cannot occur in cells wherein photosynthesis produces free O₂. Consider the colonial aquatic cyanobacterium, Anabaena, whose heterocytes are described as having "...a thickened cell wall that restricts entry of O₂ produced by neighboring cells. Intracellular connections allow heterocysts to transport fixed nitrogen to neighboring cells in exchange for carbohydrates." 62) Which two questions below arise from a careful reading of this quotation, and are most important for understanding how N₂ enters heterocysts, and how O₂ is kept out of heterocysts? 1. If carbohydrates can enter the heterocysts from neighboring cells via the "intracellular connections," how is it that O₂ doesn't also enter via this route? 2. If the cell walls of Anabaena's photosynthetic cells are permeable to O₂ and CO₂, are they also permeable to N₂? 3. If the nuclei of the photosynthetic cells contain the genes that code for nitrogen fixation, how can these cells fail to perform nitrogen fixation? 4. If the nuclei of the heterocysts contain the genes that code for photosynthesis, how can these cells fail to perform photosynthesis? 5. If the cell walls of Anabaena's heterocysts are permeable to N₂, how is it that N₂ doesn't diffuse out of the heterocysts before it can be fixed? 6. If the thick cell walls of the heterocysts exclude entry of oxygen gas, how is it that they don't also exclude the entry of nitrogen gas? A) 1 and 3 B) 1 and 6 C) 2 and 5 D) 3 and 4 E) 4 and 6

The following question refer to Figure 27.1. In this eight-year experiment, 12 populations of E. coli, each begun from a single cell, were grown in low-glucose conditions for 20,000 generations. Each culture was introduced to fresh growth medium every 24 hours. Occasionally, samples were removed from the populations, and their fitness in low-glucose conditions was tested against that of members sampled from the ancestral (common ancestor) E. coli population. Figure 27.1 43) If new genetic variation in the experimental populations arose solely by spontaneous mutations, then the most effective process for subsequently increasing the prevalence of the beneficial mutations in the population over the course of generations is A) transduction. B) binary fission. C) conjugation. D) transformation. E) meiosis.

The following table depicts characteristics of five prokaryotic species (A—E). Use the information in the table to answer the following question. 71) Which species is most likely to be found both in sewage treatment plants and in the guts of cattle? A) species A B) species B C) species C D) species D E) species E

Traditionally, whales and hippopotamuses have been classified in different orders, the Cetacea and the Artiodactyla, respectively. Recent molecular evidence, however, indicates that the whales' closest living relatives are the hippos. This has caused some zoologists to lump the two orders together into a single clade, the Cetartiodactyla. There is no consensus on whether the Cetartiodactyla should be accorded order status or superorder status. This is because it remains unclear whether the whale lineage diverged from the lineage leading to the hippos before or after the other members of the order Artiodactyla (pigs, camels, etc.) diverged (see Figure 26.2). Figure 26.2 contrasts the "Within the artiodactyls" origin of the whale lineage with the "Without the artiodactyls" origin of the whale lineage 43) If it turns out that the whale lineage diverged from the lineage leading to hippos after the divergence of the lineage leading to the pigs and other artiodactyls, and if the whales continue to be classified in the order Cetacea, then what becomes true of the order Artiodactyla? A) It becomes monophyletic. B) It becomes paraphyletic. C) It becomes polyphyletic. D) It is incorporated into the order Cetacea.

1) The legless condition that is observed in several groups of extant reptiles is the result of A) their common ancestor having been legless. B) a shared adaptation to an arboreal (living in trees) lifestyle. C) several instances of the legless condition arising independently of each other. D) individual lizards adapting to a fossorial (living in burrows) lifestyle during their lifetimes.

14) The common ancestors of birds and mammals were very early (stem) reptiles, which almost certainly possessed three-chambered hearts (two atria, one ventricle). Birds and mammals, however, are alike in having four-chambered hearts (two atria, two ventricles). The four-chambered hearts of birds and mammals are best described as A) structural homologies. B) vestiges. C) homoplasies. D) the result of shared ancestry. E) molecular homologies.

15) Chloramphenicol is an antibiotic that targets prokaryotic (70S) ribosomes, but not eukaryotic (80S) ribosomes. Which of these questions stems from this observation, plus an understanding of eukaryotic origins? A) Can chloramphenicol also be used to control human diseases that are caused by archaeans? B) Can chloramphenicol pass through the capsules possessed by many cyanobacteria? C) If chloramphenicol inhibits prokaryotic ribosomes, should it not also inhibit mitochondrial ribosomes? D) Why aren't prokaryotic ribosomes identical to eukaryotic ribosomes? E) How is translation affected in ribosomes that are targeted by chloramphenicol?

16) When using a cladistic approach to systematics, which of the following is considered most important for classification? A) shared primitive characters B) analogous primitive characters C) shared derived characters D) the number of homoplasies E) overall phenotypic similarity

18) Which of these statements about prokaryotes is correct? A) Bacterial cells conjugate to mutually exchange genetic material. B) Their genetic material is confined within vesicles known as plasmids. C) They divide by binary fission, without mitosis or meiosis. D) The persistence of bacteria throughout evolutionary time is due to their genetic homogeneity (in other words, sameness). E) Genetic variation in bacteria is not known to occur, because of their asexual mode of reproduction.

21) Nucleic acid sequences that undergo few changes over the course of evolutionary time are said to be conserved. Conserved sequences of nucleic acids A) are found in the most crucial portions of proteins. B) include all mitochondrial DNA. C) are abundant in ribosomes. D) are proportionately more common in eukaryotic introns than in eukaryotic exons. E) comprise a larger proportion of pre-mRNA (immature mRNA) than of mature mRNA.

24) A phylogenetic tree constructed using sequence differences in mitochondrial DNA would be most valid for discerning the evolutionary relatedness of A) archaeans and bacteria. B) fungi and animals. C) chimpanzees and humans. D) sharks and dolphins. E) mosses and ferns.

25) Which of the following obtain energy by oxidizing inorganic substancesenergy that is used, in part, to fix CO₂? A) photoautotrophs B) photoheterotrophs C) chemoautotrophs D) chemoheterotrophs that perform decomposition E) parasitic chemoheterotrophs

29) The most important feature that permits a gene to act as a molecular clock is A) having a large number of base pairs. B) having a larger proportion of exonic DNA than of intronic DNA. C) having a reliable average rate of mutation. D) its recent origin by a gene-duplication event. E) its being acted upon by natural selection.

3) Which statement about bacterial cell walls is false? A) Bacterial cell walls differ in molecular composition from plant cell walls. B) Cell walls prevent cells from bursting in hypotonic environments. C) Cell walls prevent cells from dying in hypertonic conditions. D) Bacterial cell walls are similar in function to the cell walls of many protists, fungi, and plants. E) Cell walls provide the cell with a degree of physical protection from the environment.

31) When it acts upon a gene, which of the following processes consequently makes that gene an accurate molecular clock? A) transcription B) directional natural selection C) mutation D) proofreading E) reverse transcription

32) The thermoacidophile, Sulfolobus acidocaldarius, lacks peptidoglycan, but still possesses a cell wall. What is likely to be true of this species? 1. It is a bacterium. 2. It is an archaean. 3. The optimal pH of its enzymes will lie above pH 7. 4. The optimal pH of its enzymes will lie below pH 7. 5. It could inhabit certain hydrothermal springs. 6. It could inhabit alkaline hot springs. A) 1, 3, and 6 B) 2, 4, and 6 C) 2, 4, and 5 D) 1, 3, and 5 E) 1, 4, and 5

37) In a hypothetical situation, a bacterium lives on the surface of a leaf, where it obtains nutrition from the leaf's nonliving, waxy covering while inhibiting the growth of other microbes that are plant pathogens. If this bacterium gains access to the inside of a leaf, however, it causes a fatal disease in the plant. Once the plant dies, the bacterium and its offspring decompose the plant. What is the correct sequence of ecological roles played by the bacterium in the situation described here? Use only those that apply. 1. nutrient recycler 2. mutualist 3. commensal 4.parasite 5. primary producer A) 1, 3, 4 B) 2, 3, 4 C) 2, 4, 1 D) 1, 2, 5 E) 1, 2, 3

4) Linnaeus was a "fixist" who believed that species remained fixed in the form in which they had been created. Linnaeus would have been uncomfortable with A) classifying organisms using the morphospecies concept. B) the scientific discipline known as taxonomy. C) phylogenies. D) nested, ever-more inclusive categories of organisms. E) a hierarchical classification scheme.

8) The typical prokaryotic flagellum features A) an internal 9 + 2 pattern of microtubules. B) an external covering provided by the plasma membrane. C) a complex "motor" embedded in the cell wall and plasma membrane. D) a basal body that is similar in structure to the cell's centrioles. E) a membrane-enclosed organelle with motor proteins.

9) The best classification system is that which most closely A) unites organisms that possess similar morphologies. B) conforms to traditional, Linnaean taxonomic practices. C) reflects evolutionary history. D) reflects the basic separation of prokaryotes from eukaryotes.

A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan. 54) Adherence to the intestinal lining by this bacterium is due to its possession of A) fimbriae. B) pili. C) a capsule. D) a flagellum. E) a cell wall with an outer lipopolysaccharide membrane.

A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan. 55) What should be true of the cell wall of this bacterium? A) Its innermost layer is composed of a phospholipid bilayer. B) After it has been subjected to Gram staining, the cell should remain purple. C) It has an outer membrane of lipopolysaccharide. D) It is mostly composed of a complex, cross-linked polysaccharide. E) Two of the responses above are correct.

A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan. 58) The cell also lacks F factors and F plasmids. Upon its death, this bacterium should be able to participate in A) conjugation. B) transduction. C) transformation. D) Three of the responses above are correct. E) Two of the responses above are correct.

A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan. 59) This bacterium derives nutrition by digesting human intestinal contents (in other words, food). Thus, this bacterium should be an A) aerobic chemoheterotroph. B) aerobic chemoautotroph. C) anaerobic chemoheterotroph. D) anaerobic chemoautotroph.

A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan. 60) This bacterium derives nutrition by digesting human intestinal contents (in other words, food). Humans lacking this bacterium have no measurable reproductive advantage or disadvantage relative to humans who harbor this bacterium. Consequently, the bacterium can be properly described as which of the following? 1. symbiont 2. endosymbiont 3. mutualist 4. commensal A) 4 only B) 1 and 2 C) 1 and 4 D) 2 and 3 E) 2 and 4

The following question refer to Figure 27.1. In this eight-year experiment, 12 populations of E. coli, each begun from a single cell, were grown in low-glucose conditions for 20,000 generations. Each culture was introduced to fresh growth medium every 24 hours. Occasionally, samples were removed from the populations, and their fitness in low-glucose conditions was tested against that of members sampled from the ancestral (common ancestor) E. coli population. Figure 27.1 44) E. coli cells typically make most of their ATP by metabolizing glucose. Under the conditions of this experiment, what should be true of E. coli's generation time (especially early in the course of the experiment, but less so later on)? A) Generation time should be the same as in the typical environment. B) Generation time should be faster than in the typical environment. C) Generation time should be slower than in the typical environment. D) It is theoretically impossible to make any predictions about generation time under these conditions.

The following table depicts characteristics of five prokaryotic species (A—E). Use the information in the table to answer the following question. 64) Which species should be able to respond most readily to taxes (plural of taxis)? A) species A B) species B C) species C D) species D E) species E

The following table depicts characteristics of five prokaryotic species (A—E). Use the information in the table to answer the following question. 65) How many of these species probably have a cell wall that partly consists of an outer membrane of lipopolysaccharide? A) only one species B) two species C) three species D) four species E) all five species

The following table depicts characteristics of five prokaryotic species (A—E). Use the information in the table to answer the following question. 67) Species D is pathogenic if it gains access to the human intestine. Which other species, if it coinhabited a human intestine along with species D, is most likely to result in a recombinant species that is both pathogenic and resistant to some antibiotics? A) species A B) species B C) species C D) species D E) species E

The next question refer to the following table, which compares the % sequence homology of four different parts (two introns and two exons) of a gene that is found in five different eukaryotic species. Each part is numbered to indicate its distance from the promoter (e.g., Intron I is the one closest to the promoter). The data reported for species A were obtained by comparing DNA from one member of species A to another member of species A. 66) Which of the following is the best explanation for the high degree of sequence homology observed in Exon I among these five species? A) It is the most-upstream exon of this gene. B) Due to alternative gene splicing, this exon is often treated as an intron. C) It codes for a polypeptide domain that has a crucial function. D) These five species must actually constitute a single species. E) This exon is rich in G-C base pairs; thus, it is more stable

The next question refer to the following table, which compares the % sequence homology of four different parts (two introns and two exons) of a gene that is found in five different eukaryotic species. Each part is numbered to indicate its distance from the promoter (e.g., Intron I is the one closest to the promoter). The data reported for species A were obtained by comparing DNA from one member of species A to another member of species A. 68) Which of these four gene parts should allow the construction of the most accurate phylogenetic tree, assuming that this is the only part of the gene that has acted as a reliable molecular clock? A) Intron I B) Exon I C) Intron VI D) Exon V

Traditionally, whales and hippopotamuses have been classified in different orders, the Cetacea and the Artiodactyla, respectively. Recent molecular evidence, however, indicates that the whales' closest living relatives are the hippos. This has caused some zoologists to lump the two orders together into a single clade, the Cetartiodactyla. There is no consensus on whether the Cetartiodactyla should be accorded order status or superorder status. This is because it remains unclear whether the whale lineage diverged from the lineage leading to the hippos before or after the other members of the order Artiodactyla (pigs, camels, etc.) diverged (see Figure 26.2). Figure 26.2 contrasts the "Within the artiodactyls" origin of the whale lineage with the "Without the artiodactyls" origin of the whale lineage 42) Placing whales and hippos in the same clade means A) that these organisms are phenotypically more similar to each other than to any others shown on the trees in Figure 26.2. B) that their morphological similarities are probably homoplasies. C) that they had a common ancestor. D) that all three of the responses are correct. E) that two of the responses are correct.

11) Some molecular data place the giant panda in the bear family (Ursidae) but place the lesser panda in the raccoon family (Procyonidae). Consequently, the morphological similarities of these two species are probably due to A) inheritance of acquired characteristics. B) sexual selection. C) inheritance of shared derived characters. D) possession of analogous structures. E) possession of shared primitive characters.

12) Although not present in all bacteria, this cell covering often enables cells that possess it to resist the defenses of host organisms, especially their phagocytic cells. A) endospore B) sex pilus C) cell wall D) capsule

15) Which of the following is true of all horizontally oriented phylogenetic trees, where time advances to the right? A) Each branch point represents a point in absolute time. B) Organisms represented at the base of such trees are descendants of those represented at higher levels. C) The fewer branch points that occur between two taxa, the more divergent their DNA sequences should be. D) The common ancestor represented by the rightmost branch point existed more recently in time than the common ancestors represented at branch points located to the left. E) The more branch points there are, the fewer taxa are likely to be represented.

17) Regarding prokaryotic genetics, which statement is correct? A) Crossing over during prophase I introduces some genetic variation. B) Prokaryotes feature the union of haploid gametes, as do eukaryotes. C) Prokaryotes exchange some of their genes by conjugation, the union of haploid gametes, and transduction. D) Mutation is a primary source of variation in prokaryote populations. E) Prokaryotes skip sexual life cycles because their life cycle is too short.

18) There is some evidence that reptiles called cynodonts may have had whisker-like hairs around their mouths. If true, then what can be properly said of hair? A) It is a shared derived character of mammals, even if cynodonts continue to be classified as reptiles. B) It is a shared derived character of the amniote clade, and not of the mammal clade. C) It is a shared ancestral character of the amniote clade, but only if cynodonts are reclassified as mammals. D) It is a shared derived character of the mammals, but only if cynodonts are reclassified as mammals.

22) Match the numbered terms to the description that follows. Choose all appropriate terms. 1. autotroph 2. heterotroph 3. phototroph 4. chemotroph a prokaryote that obtains both energy and carbon as it decomposes dead organisms A) 1 only B) 4 only C) 1 and 3 D) 2 and 4 E) 1, 3, and 4

22) Species that are not closely related and that do not share many anatomical similarities can still be placed together on the same phylogenetic tree by comparing their A) plasmids. B) mitochondrial genomes. C) homologous genes that are poorly conserved. D) homologous genes that are highly conserved.

23) Match the numbered terms to the description that follows. Choose all appropriate terms. 1. autotroph 2. heterotroph 3. phototroph 4. chemotroph an organism that obtains both carbon and energy by ingesting prey A) 1 only B) 4 only C) 1 and 3 D) 2 and 4 E) 1, 3, and 4

26) Which statement represents the best explanation for the observation that the nuclear DNA of wolves and domestic dogs has a very high degree of sequence homology? A) Dogs and wolves have very similar morphologies. B) Dogs and wolves belong to the same order. C) Dogs and wolves are both members of the order Carnivora. D) Dogs and wolves shared a common ancestor very recently.

27) Carl Woese and collaborators identified two major branches of prokaryotic evolution. What was the basis for dividing prokaryotes into two domains? A) microscopic examination of staining characteristics of the cell wall B) metabolic characteristics such as the production of methane gas C) metabolic characteristics such as chemoautotrophy and photosynthesis D) genetic characteristics such as ribosomal RNA sequences E) ecological characteristics such as the ability to survive in extreme environments

27) The reason that paralogous genes can diverge from each other within the same gene pool, whereas orthologous genes diverge only after gene pools are isolated from each other, is that A) having multiple copies of genes is essential for the occurrence of sympatric speciation in the wild. B) paralogous genes can occur only in diploid species; thus, they are absent from most prokaryotes. C) polyploidy is a necessary precondition for the occurrence of sympatric speciation in the wild. D) having an extra copy of a gene permits modifications to the copy without loss of the original gene product.

29) If archaeans are more closely related to eukaryotes than to bacteria, then which of the following is a reasonable prediction? A) Archaean DNA should have no introns. B) Archaean chromosomes should have no protein bonded to them. C) Archaean DNA should be single-stranded. D) Archaean ribosomes should be larger than typical prokaryotic ribosomes. E) Archaeans should lack cell walls.

32) Which of these would, if it had acted upon a gene, prevent this gene from acting as a reliable molecular clock? A) neutral mutations B) genetic drift C) mutations within introns D) natural selection E) most substitution mutations involving an exonic codon's third position

34) The termite gut protist, Mixotricha paradoxa, has at least two kinds of bacteria attached to its outer surface. One kind is a spirochete that propels its host through the termite gut. A second type of bacteria synthesizes ATP, some of which is used by the spirochetes. The locomotion provided by the spirochetes introduces the ATP-producing bacteria to new food sources. Which term(s) is (are) applicable to the relationship between the two kinds of bacteria? 1. mutualism 2. parasitism 3. symbiosis 4. metabolic cooperation A) 1 only B) 1 and 2 C) 2 and 3 D) 1, 3, and 4 E) 2, 3, and 4

36) If all prokaryotes on Earth suddenly vanished, which of the following would be the most likely and most direct result? A) The number of organisms on Earth would decrease by 1020%. B) Human populations would thrive in the absence of disease. C) Bacteriophage numbers would dramatically increase. D) The recycling of nutrients would be greatly reduced, at least initially. E) There would be no more pathogens on Earth.

4) The predatory bacterium, Bdellovibrio bacteriophorus, drills into a prey bacterium and, once inside, digests it. In an attack upon a gram-negative bacterium that has a slimy cell covering, what is the correct sequence of structures penetrated by B. bacteriophorus on its way to the prey's cytoplasm? 1. membrane composed mostly of lipopolysaccharide 2. membrane composed mostly of phospholipids 3. peptidoglycan 4. capsule A) 2, 4, 3, 1 B) 1, 3, 4, 2 C) 1, 4, 3, 2 D) 4, 1, 3, 2 E) 4, 3, 1, 2

41) If Figure 26.1 is an accurate depiction of relatedness, then which of the following should be correct? 1. The entire tree is based on maximum parsimony. 2. If all species depicted here make up a taxon, this taxon is monophyletic. 3. The last common ancestor of species B and C occurred more recently than the last common ancestor of species D and E. 4. Species A is the direct ancestor of both species B and species C. 5. The species present at position 3 is ancestral to C, D, and E. A) 1 and 3 B) 3 and 4 C) 2, 3, and 4 D) 1, 2, and 3

5) Which of the following is (are) problematic when the goal is to construct phylogenies that accurately reflect evolutionary history? A) polyphyletic taxa B) paraphyletic taxa C) monophyletic taxa D) Two of the responses are correct.

69) Three living species X, Y, and Z share a common ancestor T, as do extinct species U and V. A grouping that consists of species T, X, Y, and Z (but not U or V) makes up A) a valid taxon. B) a monophyletic clade. C) an ingroup, with species U as the outgroup. D) a paraphyletic group. E) a polyphyletic group.

71) To apply parsimony to constructing a phylogenetic tree, A) choose the tree that assumes all evolutionary changes are equally probable. B) choose the tree in which the branch points are based on as many shared derived characters as possible. C) base phylogenetic trees only on the fossil record, as this provides the simplest explanation for evolution. D) choose the tree that represents the fewest evolutionary changes, either in DNA sequences or morphology. E) choose the tree with the fewest branch points.

72) Based on this tree, which statement is not correct? A) The salamander lineage is a basal taxon. B) Salamanders are a sister group to the group containing lizards, goats, and humans. C) Salamanders are as closely related to goats as to humans. D) Lizards are more closely related to salamanders than to humans.

75) Which of the following statements is not true? A) Archaea and bacteria have different membrane lipids. B) Both archaea and bacteria generally lack membrane-enclosed organelles. C) The cell walls of archaea lack peptidoglycan. D) Only bacteria have histones associated with DNA. E) Only some archaea use CO₂ to oxidize H₂, releasing methane

A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan. 53) This bacterium's ability to survive in a human who is taking penicillin pills may be due to the presence of 1. penicillin-resistance genes 2. a secretory system that removes penicillin from the cell 3. a gram-positive cell wall 4. a gram-negative cell wall 5. an endospore A) 1 or 5 B) 2 or 3 C) 4 or 5 D) 2, 3, or 5 E) 2, 4, or 5

A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan. 56) Some of the proteins that allow this bacterium to swim are related (in an evolutionary sense) to proteins that A) attach to the single chromosome. B) act as restriction enzymes. C) synthesize peptidoglycan for the cell wall. D) move penicillin out of the cell. E) comprise its ribosomes.

A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan. 57) In which feature(s) should one be able to locate a complete chromosome of this bacterium? 1. nucleolus 2. prophage 3. endospore 4. nucleoid A) 4 only B) 1 and 3 C) 2 and 3 D) 3 and 4 E) 2, 3, and 4

Figure 26.5. Humans, chimpanzees, gorillas, and orangutans are members of a clade called the great apes, which shared a common ancestor about 18 million years ago (Figure 26.4). Gibbons and siamangs comprise a clade called the lesser apes. Tree-branch lengths indicate elapsed time. 58) What is true of the phylogeny in Figure 26.5? 1.It is rooted. 2. The gibbons and siamangs represent an outgroup of the great apes. 3. Chimps and humans are the closest extant sister taxa depicted here. 4. It is absolute, meaning free of error. 5. The last common ancestor of the great apes lived about 14 million years ago. A) 1, 2, and 3 B) 1, 2, and 5 C) 1, 2, 3, and 4 D) 1, 2, 3, and 5 E) 2, 3, 4, and 5

The following question refer to Figure 27.1. In this eight-year experiment, 12 populations of E. coli, each begun from a single cell, were grown in low-glucose conditions for 20,000 generations. Each culture was introduced to fresh growth medium every 24 hours. Occasionally, samples were removed from the populations, and their fitness in low-glucose conditions was tested against that of members sampled from the ancestral (common ancestor) E. coli population. Figure 27.1 41) Which of the following, if it occurs in the absence of any other type of adaptation listed here, is least reasonable in terms of promoting bacterial survival over evolutionary time in a low-glucose environment? A) increased efficiency at transporting glucose into the cell from the environment B) increased ability to survive on simple sugars, other than glucose C) increased ability to synthesize glucose from amino acid precursors D) increased reliance on glycolytic enzymes E) increased sensitivity to, and ability to move toward, whatever glucose is present in its habitat

The following question refer to Figure 27.1. In this eight-year experiment, 12 populations of E. coli, each begun from a single cell, were grown in low-glucose conditions for 20,000 generations. Each culture was introduced to fresh growth medium every 24 hours. Occasionally, samples were removed from the populations, and their fitness in low-glucose conditions was tested against that of members sampled from the ancestral (common ancestor) E. coli population. Figure 27.1 45) If the experimental population of E. coli lacks an F factor or F plasmid, and if bacteriophages are excluded from the bacterial cultures, then which of these is (are) means by which beneficial mutations might be transmitted horizontally to other E. coli cells? A) via sex pili B) via transduction C) via conjugation D) via transformation E) Two of the responses above are correct.

The following question refer to this phylogenetic tree, depicting the origins of life and of the three domains. Horizontal lines indicate instances of gene or genome transfer. Figure 26.4. A possible phylogenetic tree for the three domains of life. 51) If the early history of life on Earth is accurately depicted by Figure 26.4, then which statement is least in agreement with the hypothesis proposed by this tree? A) The last universal common ancestor of all extant species is better described as a community of organisms, rather than an individual species. B) The origin of the three domains appears as a polytomy. C) Archaean genomes should contain genes that originated in bacteria, and vice versa. D) Eukaryotes are more closely related to archaeans than to bacteria.

The next question refer to the following table, which compares the % sequence homology of four different parts (two introns and two exons) of a gene that is found in five different eukaryotic species. Each part is numbered to indicate its distance from the promoter (e.g., Intron I is the one closest to the promoter). The data reported for species A were obtained by comparing DNA from one member of species A to another member of species A. 65) Based on the tabular data, and assuming that time advances vertically, which cladogram (a type of phylogenetic tree) is the most likely depiction of the evolutionary relationships among these five species? A. SEE IMAGE B. SEE IMAGE C. SEE IMAGE D. SEE IMAGE

The next question refer to the following table, which compares the % sequence homology of four different parts (two introns and two exons) of a gene that is found in five different eukaryotic species. Each part is numbered to indicate its distance from the promoter (e.g., Intron I is the one closest to the promoter). The data reported for species A were obtained by comparing DNA from one member of species A to another member of species A. 67) Regarding these sequence homology data, the principle of maximum parsimony would be applicable in A) distinguishing introns from exons. B) determining degree of sequence homology. C) selecting appropriate genes for comparison among species. D) inferring evolutionary relatedness from the number of sequence differences.

Traditionally, whales and hippopotamuses have been classified in different orders, the Cetacea and the Artiodactyla, respectively. Recent molecular evidence, however, indicates that the whales' closest living relatives are the hippos. This has caused some zoologists to lump the two orders together into a single clade, the Cetartiodactyla. There is no consensus on whether the Cetartiodactyla should be accorded order status or superorder status. This is because it remains unclear whether the whale lineage diverged from the lineage leading to the hippos before or after the other members of the order Artiodactyla (pigs, camels, etc.) diverged (see Figure 26.2). Figure 26.2 contrasts the "Within the artiodactyls" origin of the whale lineage with the "Without the artiodactyls" origin of the whale lineage 45) One morphological feature of modern cetaceans is a vestigial pelvic girdle. If it is determined that cetacean lineage diverged from the artiodactyls' lineage after the divergence of pigs and other artiodactyla, then what should be true of the vestigial pelvic girdle of cetaceans? A) It should be considered a shared ancestral character of the cetartiodactyls. B) It should be considered a shared derived character of the cetartiodactyls. C) It should be considered a shared ancestral character of the cetaceans. D) It should be considered a shared derived character of the cetaceans.

Traditionally, whales and hippopotamuses have been classified in different orders, the Cetacea and the Artiodactyla, respectively. Recent molecular evidence, however, indicates that the whales' closest living relatives are the hippos. This has caused some zoologists to lump the two orders together into a single clade, the Cetartiodactyla. There is no consensus on whether the Cetartiodactyla should be accorded order status or superorder status. This is because it remains unclear whether the whale lineage diverged from the lineage leading to the hippos before or after the other members of the order Artiodactyla (pigs, camels, etc.) diverged (see Figure 26.2). Figure 26.2 contrasts the "Within the artiodactyls" origin of the whale lineage with the "Without the artiodactyls" origin of the whale lineage 47) It was once thought that cetaceans had evolved from an extinct group of mammals called the mesonychids. If, in the future, it is determined that some organisms currently classified as cetaceans did actually evolve from mesonychids, whereas other cetaceans evolved from artiodactyl stock, then what will be true of the order Cetacea? A) It will be paraphyletic. B) It will be polyphyletic. C) It will need to be thrown out or modified if classification is to reflect evolutionary history. D) Two of the responses are correct.

Traditionally, zoologists have placed birds in their own class, Aves. More recently, molecular evidence has shown that birds are more closely related to reptiles than their anatomy reveals. Genetically, birds are more closely related to crocodiles than crocodiles are to turtles. Thus, bird anatomy has become highly modified as they have adapted to flight, without their genes having undergone nearly as much change. 62) Taxonomically, what should be done with the birds? A) The traditional stance is correct. Such dramatic morphological change as undergone by birds merits that the birds be placed in their own order, separate from the reptiles. B) The birds should be reclassified, and their new taxon should be the subclass Aves. Genetic similarity trumps morphological dissimilarity. C) The rest of the reptiles should be reclassified as a subclass within the class Aves. D) Science is consensual. Taxonomy is a science. Variant classification schemes involving the birds should be tolerated until consensus is reached.

Traditionally, zoologists have placed birds in their own class, Aves. More recently, molecular evidence has shown that birds are more closely related to reptiles than their anatomy reveals. Genetically, birds are more closely related to crocodiles than crocodiles are to turtles. Thus, bird anatomy has become highly modified as they have adapted to flight, without their genes having undergone nearly as much change. 63) Traditional zoologists have long agreed that birds evolved from dinosaurs. What keeps such zoologists from agreeing that birds, like dinosaurs, should be considered reptiles? A) There is not yet enough evidence to be sure. B) Stubbornness, insofar as they are unwilling to change their thinking when new data warrants it. C) They deny the validity of genetic molecular data. D) They differ in what they consider to be important traits for assigning organisms to the class Reptilia.

10) Which statement about the genomes of prokaryotes is correct? A) Prokaryotic genomes are diploid throughout most of the cell cycle. B) Prokaryotic chromosomes are sometimes called plasmids. C) Prokaryotic cells have multiple chromosomes, "packed" with a relatively large amount of protein. D) The prokaryotic chromosome is not contained within a nucleus but, rather, is found at the nucleolus. E) Prokaryotic genomes are composed of circular DNA.

12) The importance of computers and of computer software to modern cladistics is most closely linked to advances in A) light microscopy. B) radiometric dating. C) fossil discovery techniques. D) Linnaean classification. E) molecular genetics.

17) Cladograms (a type of phylogenetic tree) constructed from evidence from molecular systematics are based on similarities in A) morphology. B) the pattern of embryological development. C) biochemical pathways. D) habitat and lifestyle choices. E) mutations to homologous genes.

19) A researcher wants to determine the genetic relatedness of several breeds of dog (Canis lupus familiaris). The researcher should compare homologous sequences of this type of biochemical________which can be described as ________. A) fatty acids; highly conserved B) lipids; poorly conserved C) proteins; highly conserved D) amino acids; highly conserved E) nucleic acids, poorly conserved

19) Which of the following is least associated with the others? A) horizontal gene transfer B) genetic recombination C) conjugation D) transformation E) binary fission

20) In Fred Griffith's experiments, harmless R strain pneumococcus became lethal S strain pneumococcus as the result of which of the following? 1. horizontal gene transfer 2. transduction 3. conjugation 4. transformation 5. genetic recombination A) 2 only B) 4 only C) 2 and 5 D) 1, 3, and 5 E) 1, 4, and 5

26) Mitochondria are thought to be the descendants of certain alpha proteobacteria. They are, however, no longer able to lead independent lives because most genes originally present on their chromosome have moved to the nuclear genome. Which phenomenon accounts for the movement of these genes? A) plasmolysis B) conjugation C) translation D) endocytosis E) horizontal gene transfer

28) Paralogous genes that have lost the function of coding for any functional gene product are known as "pseudogenes." Which of these is a valid prediction regarding the fate of pseudogenes over evolutionary time? A) They will be preserved by natural selection. B) They will be highly conserved. C) They will ultimately regain their original function. D) They will be transformed into orthologous genes. E) They will have relatively high mutation rates.

3) If organisms A, B, and C belong to the same class but to different orders and if organisms D, E, and F belong to the same order but to different families, which of the following pairs of organisms would be expected to show the greatest degree of structural homology? A) A and B B) A and C C) B and D D) C and F E) D and F

30) Neutral theory proposes that A) molecular clocks are more reliable when the surrounding pH is close to 7.0. B) most mutations of highly conserved DNA sequences should have no functional effect. C) DNA is less susceptible to mutation when it codes for amino acid sequences whose side groups (or R groups) have a neutral pH. D) DNA is less susceptible to mutation when it codes for amino acid sequences whose side groups (or R groups) have a neutral electrical charge. E) a significant proportion of mutations are not acted upon by natural selection.

33) A fish that has been salt-cured subsequently develops a reddish color. You suspect that the fish has been contaminated by the extreme halophile, Halobacterium. Which of these features of cells removed from the surface of the fish, if confirmed, would support your suspicion? 1. the presence of the same photosynthetic pigments found in cyanobacteria 2. cell walls that lack peptidoglycan 3. cells that are isotonic to conditions on the surface of the fish 4. cells containing bacteriorhodopsin 5. the presence of very large numbers of ion pumps in its plasma membrane A) 2 and 5 B) 3 and 4 C) 1, 4, and 5 D) 3, 4, and 5 E) 2, 3, 4, and 5

36) Which kingdom has been replaced with two domains? A) Plantae B) Fungi C) Animalia D) Protista E) Monera

39) Broad-spectrum antibiotics inhibit the growth of most intestinal bacteria. Consequently, assuming that nothing is done to counter the reduction of intestinal bacteria, a hospital patient who is receiving broad-spectrum antibiotics is most likely to become A) unable to fix carbon dioxide. B) antibiotic resistant. C) unable to fix nitrogen. D) unable to synthesize peptidoglycan. E) deficient in certain vitamins and nutrients.

50) Which of the following items does not necessarily exist in a simple linear relationship with the number of gene-duplication events when placed as the label on the vertical axis of the following graph? A) number of genes B) number of DNA base pairs C) genome size D) mass (in picograms) of DNA E) phenotypic complexity

6) In a bacterium that possesses antibiotic resistance and the potential to persist through very adverse conditions, such as freezing, drying, or high temperatures, DNA should be located within, or be part of, which structures? 1. nucleoid region 2. endospore 3. fimbriae 4. plasmids A) 1 only B) 1 and 2 only C) 1 and 4 only D) 2 and 4 only E) 1, 2, and 4

73) Genetic variation in bacterial populations cannot result from A) transduction. B) transformation C) conjugation D) mutation. E) meiosis.

Figure 26.5. Humans, chimpanzees, gorillas, and orangutans are members of a clade called the great apes, which shared a common ancestor about 18 million years ago (Figure 26.4). Gibbons and siamangs comprise a clade called the lesser apes. Tree-branch lengths indicate elapsed time. 60) From Figure 26.5, which other event occurred closest in time to the divergence of gorillas from the lineage that led to humans and chimps? A) the divergence of chimps and humans B) the divergence of Dryopithecus and Ouranopithecus C) the divergence of gibbons and siamangs D) could be either the divergence of chimps and humans OR of Dryopithecus and Ouranopithecus E) could be either the divergence of chimps and humans OR of gibbons and siamangs

Figure 26.5. Humans, chimpanzees, gorillas, and orangutans are members of a clade called the great apes, which shared a common ancestor about 18 million years ago (Figure 26.4). Gibbons and siamangs comprise a clade called the lesser apes. Tree-branch lengths indicate elapsed time. 61) Which of these can be properly inferred from the phylogeny in Figure 26.5? A) Chimps and humans evolved from gorillas. B) The lesser apes are genetically more distinct from each other than the members of the great apes are from each other. C) Orangutans have existed for about 14 million years. D) Chimps and humans should share more homoplasies than should chimps and gorillas. E) Together, the lesser apes and great apes form a clade.

The following question refer to Figure 27.1. In this eight-year experiment, 12 populations of E. coli, each begun from a single cell, were grown in low-glucose conditions for 20,000 generations. Each culture was introduced to fresh growth medium every 24 hours. Occasionally, samples were removed from the populations, and their fitness in low-glucose conditions was tested against that of members sampled from the ancestral (common ancestor) E. coli population. Figure 27.1 42) If the vertical axis of Figure 27.1 refers to "Darwinian fitness," then which of the following is the most valid and accurate measure of fitness? A) number of daughter cells produced per mother cell per generation B) amount of ATP generated per cell per unit time C) average swimming speed of cells through the growth medium D) amount of glucose synthesized per unit time E) number of generations per unit time

The following table depicts characteristics of five prokaryotic species (A—E). Use the information in the table to answer the following question. 69) Which species is most self-sustaining in terms of obtaining nutrition in environments containing little fixed nitrogen or carbon? A) species A B) species B C) species C D) species D E) species E

The following table depicts characteristics of five prokaryotic species (A—E). Use the information in the table to answer the following question. 72) Which species is probably an important contributor to the base of aquatic food chains as a primary producer? A) species A B) species B C) species C D) species D E) species E

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