Question 1

The question refers to the following table, which compares the percent 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 (for example, 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
$$\begin{array} { | l | l | l | l | l |} 
\hline \text { Species } & \text { Intron I } & \text { Exon I } & \text { Intron VI } & \text { Exon V } \
\hline  A  & 100 \% & 100 \% & 100 \% & 100 \% \
\hline B & 98 \% & 99 \% & 82 \% & 96 \% \
\hline  C& 98 \% & 99 \% & 89 \% & 96 \% \
\hline   D  & 99 \% & 99 \% & 92 \% & 97 \% \
\hline   E  & 98 \% & 99 \% & 80 \% & 94 \% \
\hline
\end{array}$$
-Based on the tabular data, and assuming that time advances vertically, which phylogenetic tree is the most likely depiction of the evolutionary relationships among these five species?

Accepted Answer

A) 
 
B) 
 
C) 
 
D)

Question 2

Humans, chimpanzees, gorillas, and orangutans are members of a clade called the "great apes", which shared a common ancestor about 15 million years ago. Gibbons and siamangs comprise a clade called the "lesser apes". Tree-branch lengths indicate elapsed time.
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 ________.

Accepted Answer

A)  polyphyletic 
B)  paraphyletic 
C)  monophyletic 
D)  into a new order

Question 3

Imagine that you discovered the following information:
Feature Bacteria Archaea Eukaryotes
RNA polymerase small, simple complex complex
Introns absent present present
Antibiotic sensitivity sensitive insensitive insensitive
Membrane Lipids C chains unbranched C chains branched C chains branched
These data would support which of the following conclusions?

Accepted Answer

A)  Eukaryotes share a more recent common ancestor with bacteria than with archaea. 
B)  Bacteria are the only one of the three groups that lacks a nucleus. 
C)  Archaea are more similar to bacteria than to eukaryotes. 
D)  Eukaryotes are more similar to archaea than to bacteria.

Question 4

Concerning growth in genome size over evolutionary time, which of these is least associated with the others?

Accepted Answer

A)  orthologous genes 
B)  gene duplications 
C)  paralogous genes 
D)  gene families

Question 5

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 ________.

Accepted Answer

A)  homology 
B)  convergent evolution 
C)  common ancestry 
D)  retro-evolution by humans

Question 6

Which of the following would be most useful in creating a phylogenetic tree of a taxon?

Accepted Answer

A)  morphological data from fossil and living species 
B)  a knowledge of colour patterns in fossil and living species 
C)  a knowledge of mutation rates in modern species 
D)  morphological data from fossil species

Question 7

The phylogenetic tree shown ________.

Accepted Answer

A)  depicts uncertainty about whether the bryophytes or the vascular plants evolved first 
B)  depicts an evolutionary hypothesis 
C)  includes evolution of convergent characteristics 
D)  indicates that seeds are a shared ancestral character of all vascular plants

Question 8

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 ________.

Accepted Answer

A)  structural homologies 
B)  vestiges 
C)  structural analogies 
D)  the result of shared ancestry

Question 9

Based on the tree below, which statement is not correct?

Accepted Answer

A)  Goats and humans form a sister group. 
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.

Question 10

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?

Accepted Answer

A)  mtDNA 
B)  rRNA genes 
C)  morphological 
D)  ecological

Question 11

-Which tree depicts the microsporidians as a sister group of the ascomycetes?

Accepted Answer

A)  I 
B)  II 
C)  III 
D)  IV

Question 12

Which of the following items is most likely to form a simple linear relationship with the number of gene-duplication events, when placed as the label on the vertical axis of the following graph?

Accepted Answer

A)  number of mitochondria 
B)  number of cells/organism 
C)  genome size 
D)  phenotypic complexity

Question 13

Your professor wants you to construct a phylogenetic tree of orchids. She gives you tissue from seven orchid species and one lily. What is the most likely reason she gave you the lily?

Accepted Answer

A)  to serve as an outgroup 
B)  to see if the lily is a cryptic orchid species 
C)  to see if the lily and the orchids show all the same shared derived characters 
D)  to demonstrate likely homoplasies

Question 14

There is some evidence that reptiles called cynodonts may have had whisker-like hairs around their mouths. If true, then hair is a shared ________.

Accepted Answer

A)  derived character of mammals, even if cynodonts continue to be classified as reptiles 
B)  derived character of all vertebrates and not of the mammal clade 
C)  ancestral character of the all vertebrates, but only if cynodonts are reclassified as mammals 
D)  derived character of mammals, but only if cynodonts are reclassified as mammals

Question 15

Giardia intestinalis can cause disease in several different mammalian species, including humans. Giardia organisms (G. intestinalis) that infect humans are similar morphologically to those that infect other mammals, thus they have been considered a single species. However, G. intestinalis has been divided into different subgroups based on their host and a few other characteristics.
In 1999, a DNA sequence comparison study tested the hypothesis that these subgroups actually constitute different species. The following phylogenetic tree was constructed from the sequence comparison of rRNA from several subgroups of G. intestinalis and a few other morphologically distinct species of Giardia. The researchers concluded that the subgroups of Giardia are sufficiently different from one another genetically that they could be considered different species. (T. Monis, et al. 1999. Molecular systematics of the parasitic protozoan Giardia intestinalis. Mol. Biol. Evol. 16[9]:1135-44.) 
-
According to the phylogenetic tree in the figure above, G. intestinalis constitutes a ________ group.

Accepted Answer

A)  analytic 
B)  monophyletic 
C)  polyphyletic 
D)  paraphyletic

Question 16

- If the figure is an accurate depiction of relatedness, then which of the following should be an accurate statement?

Accepted Answer

A)  If all species depicted here make up a taxon, this taxon is monophyletic. 
B)  The species present at position 4 is ancestral to species E, but not species D. 
C)  Species C is more closely related to species B than D is to B 
D)  The species present at position 3 is ancestral to C, D, and E.

Question 17

In a comparison of birds and mammals, the condition of having four limbs is

Accepted Answer

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.

Question 18

Eukaryotes 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 ________.

Accepted Answer

A)  plasmids 
B)  mitochondrial genomes 
C)  homologous genes that are poorly conserved 
D)  homologous genes that are highly conserved

Question 19

Applying the principle of parsimony to the trait "ability to fly", which of the two phylogenetic trees is better?

Accepted Answer

A)  Tree 1 
B)  Tree 2 
C)  Both trees are equally parsimonious. 
D)  Since the trees show different evolutionary relationships, you cannot determine which is more parsimonious.

Question 20

A phylogenetic tree constructed using sequence differences in mitochondrial DNA would be most valid for discerning the evolutionary relatedness of ________.

Accepted Answer

A)  archaeans and bacteria 
B)  fungi and animals 
C)  chimpanzees and humans 
D)  sharks and dolphins

Exam 26: Phylogeny and the Tree of Life