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.
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.
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
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.
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.
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.
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
The following questions 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.
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
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
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.
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.
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
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.
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
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
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
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.
Scenario Questions
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.
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.
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.
21
The next questions 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.
% Sequence Homology
Species
Intron I
Exon I
Intron VI
Exon V
A
100%
100%
100%
100%
B
98%
99%
82%
96%
C
98%
99%
89%
96%
D
99%
99%
92%
97%
E
98%
99%
80%
94%
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)
B)
C)
D)
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.
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.
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
End-of-Chapter Questions
The following questions are from the end-of–chapter “Test Your Understanding” section in Chapter 26
of the textbook.
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.
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.
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.
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