AP Bio Chapter 26 Practice: Phylogeny and the Tree of Life

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.

C, several instances of the legless condition arising independently of each other

The scientific discipline concerned with naming organisms is called

A) taxonomy.

B) cladistics.

C) binomial nomenclature

D) systematics.

E) phylocode

A, taxonomy

The various taxonomic levels (viz, 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) the body sizes of the organisms assigned to each.

C) their inclusiveness.

D) the relative genome sizes of the organisms assigned to each.

E) morphological characters that are applicable to all organisms.

C, their inclusiveness

Which of these illustrates the correct representation of the binomial scientific name for the African lion?

A) Panthera leo

B) panthera leo

C) Panthera leo

D) Panthera Leo

E) Panthera leo (italics)

E) Panthera leo (italics)

A phylogenetic tree that is ʺrootedʺ is one

A) that extends back to the origin of life on Earth.

B) at whose base is located the common ancestor of all taxa depicted on that tree.

C) that illustrates the rampant gene swapping that occurred early in lifeʹs history.

D) that indicates our uncertainty about the evolutionary relationships of the taxa depicted on the tree.

E) with very few branch points.

B, at whose base is located the common ancestor of all taxa depicted on that tree

The correct sequence, from the most to the least comprehensive, of the taxonomic levels listed here is

A) family, phylum, class, kingdom, order, species, and genus.

B) kingdom, phylum, class, order, family, genus, and species.

C) kingdom, phylum, order, class, family, genus, and species.

D) phylum, kingdom, order, class, species, family, and genus.

E) phylum, family, class, order, kingdom, genus, and species.

B, kingdom, phylum, class, order, family, genus, and species

The common housefly belongs to all of the following taxa. Assuming you had access to textbooks or other scientific literature, knowing which of the following should provide you with the most specific information about the common housefly?

A) order Diptera

B) family Muscidae

C) genus Musca

D) class Hexapoda

E) phylum Arthropoda

C, genus Musca

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

E) D and F

Darwin analogized the effects of evolution as the above-ground portion of a many-branched tree, with extant species being the tips of the twigs. The common ancestor of two species is most analogous to which anatomical tree part?

A) a single twig that gets longer with time

B) a node where two twigs diverge

C) a twig that branches with time

D) the trunk

E) neighboring twigs attached to the same stem

B, a node where two twigs diverge

Dozens of potato varieties exist, differing from each other in potato-tuber size, skin color, flesh color, and shape. One might construct a classification of potatoes based on these morphological traits. Which of these criticisms of such a classification scheme is most likely to come from an adherent of the phylocode method of classification?

A) Flesh color, rather than skin color, is a valid trait to use for classification because it is less susceptible to change with the age of the tuber.

B) Flower color is a better classification criterion, because below-ground tubers can be influenced by minerals in the soil as much as by their genes.

C) A more useful classification would codify potatoes based on the texture and flavor of their flesh, because this is what humans are concerned with.

D) The most accurate phylogenetic code is that of Linnaeus. Classify potatoes based on Linnaean principles; not according to their color.

E) The only biologically valid classification of potato varieties is one that accurately reflects their genetic and evolutionary relatedness.

E, the only biological valid classification of potato varieties is one that accurately reflects their genetic and evolutionary relatedness

The term ʺhomoplasyʺ is most applicable to which of these features?

A) the legless condition found in various types of extant lizards

B) the 5-digit condition of human hands and bat wings

C) the beta-hemoglobin genes of mice and of humans

D) the fur that covers Australian moles and North American moles

E) the basic skeletal features of dog forelimbs and cat forelimbs

A, the legless condition found in various types of extant lizards

If, someday, an archaean cell is discovered whose SSU-rRNA sequence is more similar to that of humans than the sequence of mouse SSU-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) co-evolution of humans and that archaean.

B, homplasy

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) corroborates the classification scheme in use at the time of Charles Darwin.

E) reflects the basic separation of prokaryotes from eukaryotes.

C, reflects evolutionary history

Which of the following pairs are the best examples of homologous structures?

A) bat wing and human hand

B) owl wing and hornet wing

C) porcupine quill and cactus spine

D) bat forelimb and bird wing

E) Australian mole and North American mole

A, bat wing and human hand

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.

D) possession of analogous structures

In angiosperm plants, flower morphology can be very intricate. If a tree, such as a New Mexico locust, has flowers that share many morphological intricacies with flowers of the sweet pea vine, then the most likely explanation for these floral similarities is the same general explanation for the similarities between the

A) dorsal fins of sharks and of dolphins.

B) reduced eyes of Australian moles and North American moles.

C) scales on moth wings and the scales of fish skin.

D) cranial bones of humans and those of chimpanzees.

E) adaptations for flight in birds and adaptations for flight in bats.

D, cranial bones of humans and those of chimpanzees

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.

E, molecular genetics

Which mutation should least require realignment of homologous regions of a gene that is common to several related species?

A) 3-base insertion

B) 1-base substitution

C) 4-base insertion

D) 1-base deletion

E) 3-base deletion

B, 1-base substitution

The common ancestors of birds and mammals were very early (stem) reptiles, which almost certainly possessed 3-chambered hearts (2 atria, 1 ventricle). Birds and mammals, however, are alike in having 4-chambered hearts (2 atria, 2 ventricles). The 4-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.

C, homplasies

Generally, within a lineage, the largest number of shared derived characters should be found among two organisms that are members of the same

A) kingdom.

B) class.

C) domain.

D) family.

E) order.

D, family

If this evolutionary tree 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) 2 and 5

B) 1 and 3

C) 3and4

D) 2, 3, and 4

E) 1, 2, and 3

E, 1, 2, and 3

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

A) A

Which of the following is not 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 ancestral to those represented at higher levels.

C) The more 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 more taxa are likely to be represented.

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.

Ultimately, which of these serves as the basis for both the principle of maximum parsimony and the principle that shared complexity indicates homology rather than analogy?

A) the laws of thermodynamics

B) Boyleʹs law

C) the laws of probability

D) chaos theory

E) Hutchinsonʹs law

C, the laws of probability

Shared derived characters are most likely to be found in taxa that are

A) paraphyletic.

B) polyphyletic.

C) monophyletic.

C, monophyletic

A taxon, all of whose members have the same common ancestor, is

A) paraphyletic.

B) polyphyletic.

C) monophyletic.

C, monophyletic

The term that is most appropriately associated with clade is

A) paraphyletic.

B) polyphyletic.

C) monophyletic.

C, monophyletic

If birds are excluded from the class Reptilia, the term that consequently describes the class Reptilia is

A) paraphyletic.

B) polyphyletic.

C) monophyletic.

A, paraphyletic

If the eukaryotic condition arose, independently, several different times during evolutionary history, and if ancestors of these different lineages are extant and are classified in the domain Eukarya, then the domain Eukarya would be

A) paraphyletic.

B) polyphyletic.

C) monophyletic.

B, polyphyletic

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

C, shared derived characters

The four-chambered hearts of birds and the four-chambered hearts of mammals evolved independently of each other. If one were unaware of this independence, then one might logically conclude that

A) the birds were the first to evolve a 4-chambered heart.

B) birds and mammals are more distantly related than is actually the case.

C) early mammals possessed feathers.

D) the common ancestor of birds and mammals had a four-chambered heart.

E) birds and mammals should be placed in the same family.

D, the common ancestor of birds and mammals had a four-chambered heart

Phylogenetic hypotheses (such as those represented by phylogenetic trees) are strongest when

A) they are based on amino acid sequences from homologous proteins, as long as the genes that code for such proteins contain no introns.

B) each clade is defined by a single derived character.

C) they are supported by more than one kind of evidence, such as when fossil evidence corroborates molecular evidence.

D) they are accepted by the foremost authorities in the field, especially if they have won Nobel Prizes.

E) they are based on a single DNA sequence that seems to be a shared derived sequence.

C, they are supported by more than one kind of evidence, such as when fossil evidence corroborates molecular evidence

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.

E, mutations to homologous genes

A researcher wants to determine the genetic relatedness of several breeds of dog (Canis familiaris). The researcher should compare homologous sequences of __________ that are known to be __________.

A) carbohydrates; poorly conserved

B) fatty acids; highly conserved

C) lipids; poorly conserved

D) nucleic acids; poorly conserved

E) amino acids; highly conserved

D, nucleic acids; poorly conserved

Concerning growth in genome size over evolutionary time, which of these does not belong with the others?

A) orthologous genes

B) gene duplications

C) paralogous genes

D) gene families

A, orthologous genes

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.

C, are abundant in ribosomes

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) chloroplast genomes.

C) mitochondrial genomes.

D) homologous genes that are poorly conserved.

E) homologous genes that are highly conserved.

E, homologous genes that are highly conserved

Which kind of DNA should provide the best molecular clock for gauging 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 non-crucial part of a polypeptide

A, that coding for ribosomal RNA

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) Hawaiian silverswords or chimpanzees and humans

D) sharks and dolphins

E) mosses and ferns.

C, Hawaiian silverswords or chimpanzees and humans

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

B, mitochondrial DNA

Which statement represents the best explanation for the observation that the nuclear DNA of wolves and domestic dogs has a very high degree of 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.

E) Convergent evolution has occurred.

D, Dogs and wolves shared a common ancestor very recently.

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.

D, having an extra copy of gene permits modifications to the copy without loss of original gene product

If the genes of yeast are 50% orthologous to those of humans, and if the genes of mice are 99% orthologous to those of humans, then what percentage of the genes of fish might one validly predict to be orthologous to the genes of humans?

A) 10%

B) 30%

C) 40%

D) 50%

E) 80%

E, 80%

What is true of gene duplication (NOTE: gene duplication is a process that is distinct from DNA replication)?

A) It is a type of point mutation.

B) Its occurrence is limited to diploid species.

C) Its occurrence is limited to organisms without functional DNA-repair enzymes.

D) It is most similar in its effects to a deletion mutation.

E) It can increase the size of a genome over evolutionary time.

E, it can increase the size of a genome over evolutionary time

Paralogous genes that have lost the function of coding for a functional gene product are known as ʺpseudogenes.ʺ 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.

E, they will have relatively high mutation rates

Theoretically, molecular clocks are to molecular phylogenies as radiometric dating is to phylogenies that are based on the

A) fossil record.

B) geographic distribution of extant species.

C) morphological similarities among extant species.

D) amino acid sequences of homologous polypeptides.

A, fossil record

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.

C, having a reliable average rate of mutation

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 is not acted upon by natural selection.

E, a significant proportion of mutations is not acted upon by natural selection

When it acts upon a gene, which of these processes consequently makes that gene an accurate molecular clock?

A) transcription

B) directional natural selection

C) mutation

D) proofreading

E) reverse transcription

C, mutation

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 codonʹs 3rd position

D) natural selection

The HIV genomeʹs reliably high rate of change permits it to serve as a molecular clock. Which of these features is most responsible for this genomeʹs high rate of change?

A) the relatively low number of nucleotides in the genome

B) the relatively small number of genes in the genome

C) the genomeʹs ability to insert itself into the genome of the host

D) the lack of proofreading by the enzyme that converts HIVʹs RNA genome into a DNA

genome

D, the lack of proofreading by the enzyme that converts HIV's RNA genome into a DNA genome

Which of these 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, is more stable.

C, it codes for a polypeptide domain that has a crucial fucntion

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.

D, inferring evolutionary relatedness from the number of sequence differences

Which of these is the best explanation for the relatively low level of sequence homology observed in Intron VI?

A) Mutations that occur here are neutral; thus, are neither selected for nor against, and thereby accumulate over time.

B) Its higher mutation rate has resulted in its highly conserved nature.

C) The occurrence of molecular homoplasy explains it.

D) This intron is not actually homologous, having resulted from separate bacteriophage-induced transduction events in these five species.

A, mutations that occur here are neutral; thus, are neither selected for nor against, and thereby accumulate over time

Which of these is the best explanation for Intron Iʹs relatively high sequence homology among these five species?

A) It is the most-upstream of this geneʹs introns.

B) It was once an exon, but became intronic in the common ancestor of these five species.

C) Due to alternative gene splicing, it is often treated as an exon in these five species; as an exon, it codes for an important part of a polypeptide.

D) It has a relatively high average rate of mutation.

C, due to alternative gene splicing, it is often treated as an exon in these five species; as an exon, it codes for an important part of a polypeptide

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

C, Intron VI

Which process hinders clarification of the deepest branchings in a phylogenetic tree that depicts the origins of the three domains?

A) binary fission

B) mitosis

C) meiosis

D) horizontal gene transfer

E) gene duplication

D, horizontal gene transfer

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

A, molecular

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

C, the nutritional modes they employ

Which is an obsolete kingdom that includes prokaryotic organisms?

A) Plantae

B) Fungi

C) Animalia

D) Protista

E) Monera

E, monera

Members of which kingdom have cell walls and are all heterotrophic?

A) Plantae

B) Fungi

C) Animalia

D) Protista

E) Monera

B, fungi

Which kingdom has been replaced with two domains?

A) Plantae

B) Fungi

C) Animalia

D) Protista

E) Monera

E, Monera

Which eukaryotic kingdom is polyphyletic and therefore not acceptable, based on cladistics?

A) Plantae

B) Fungi

C) Animalia

D) Protista

E) Monera

D, Protista

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

A, plantae

The human nuclear genome includes hundreds of genes that are orthologs of bacterial genes, and hundreds of other genes that are orthologs of archaean genes. This finding can be explained by proposing that

A) neither archaea nor bacteria contain paralogous genes.

B) the eukaryotic lineage leading to humans involved at least one fusion of an ancient bacterium with an ancient archaean.

C) the infection of humans by bacteriophage introduced prokaryotic genes into the human genome.

D) horizontal gene transfer did not occur to any significant extent among the prokaryotic ancestors of humans.

B, the eukaryotic lineage leading to humans involved at least one fusion of an ancient bacterium with an ancient archaean

A large proportion of archaeans are ʺextremophiles,ʺ so called because they inhabit extreme environments with high acidity and/or high 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 these 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 amount of genetic change, the branches of the extremophiles should be shorter, relative to branches of 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.

B, on a phylogenetic tree whose branch lengths are proportional to amount of genetic change, the branches of the extremophiles should be shorter, relative to branches of the non-extremophilic archaeans

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.

C) phylogenies.

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.

D) Two of the responses are correct.

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.

B) notion of hypothetical phylogenies.

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.

D) It is a shared derived character of the mammals, but only if cynodonts are reclassified as mammals.

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.

C) that they had a common ancestor.

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.

B) It becomes paraphyletic.

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.

A) It should be considered as one monophyletic order.

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.

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

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

A) 1 only

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.

D) Two of the responses are correct.

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.

B) In the "Without" tree, pigs are more closely related to hippos than are whales.

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 BE.
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 BE, 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 BE 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.

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.

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

E) phenotypic complexity

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.

D) Eukaryotes are more closely related to archaeans than to bacteria.

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.

52) Which of these processes can be included among those responsible for the horizontal components of Figure 26.4?
A) endosymbiosis
B) mitosis
C) binary fission
D) point mutations
E) S phase of the cell cycle

A) endosymbiosis

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.

53) Which portion of Figure 26.4 may ultimately be better depicted as a "ring"?
A) the bacterial lineage
B) the archaean lineage
C) the eukaryotic lineage
D) the trunk of the tree
E) the part corresponding to the first living cell on Earth

D) the trunk of the tree

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.

D) genera.

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.

55) Together, the lesser apes and great apes shared a common ancestor most recently with other members of their
A) order.
B) class.
C) subclass.
D) subfamily.
E) family.

A) order.

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.

56) From Figure 26.5, to which of the extant apes are orangutans most closely related?
A) gibbons and siamangs
B) Dryopithecus and Ouranopithecus
C) gorillas
D) chimps
E) chimps, gorillas, and humans

E) chimps, gorillas, and humans

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.

B) paraphyletic.

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

D) 1, 2, 3, and 5

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

B) 1, 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.

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

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.

E) Together, the lesser apes and great apes form a clade.

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.

D) Science is consensual. Taxonomy is a science. Variant classification schemes involving the birds should be tolerated until consensus is reached.