Phylogenetics, Molecular Evolution, and Bioinformatics Chapter 26 Exam Questions with Verified
Solutions Latest Update ( Graded A+)
The legless condition that is observed in several groups of living reptiles is the result of _____.
Select one:
a. their common ancestor having been legless
b. a shared adaptation to living in trees
c. several instances of the legless condition arising independently of each other
d. individual lizards adapting to a burrowing lifestyle during their lifetimes
e. all other reptiles having independently evolved legs; the legless condition is ancestral - Answers c.
several instances of the legless condition arising independently of each other
Concerning growth in genome size over evolutionary time, which of these is LEAST associated with the
others?
Select one:
a. orthologous genes
b. gene duplications
c. paralogous genes
d. gene families - Answers a. orthologous genes
gene family: A gene family is a set of several similar genes, formed by duplication of a single original
gene, and generally with similar biochemical functions
paralogous genes: homologous genes that occur within one species and have diverged after a
duplication event. Unlike orthologous genes, a paralogous gene is a new gene that holds a new function.
These genes arise during gene duplication where one copy of the gene receives a mutation that gives
rise to a new gene with a new function, though the function is often related to the role of the ancestral
gene.
orthologous genes: homologous genes that diverged after a speciation event. The genes generally
maintain a similar function to that of the ancestral gene in which they evolved from
, In a comparison of birds and mammals, having four limbs is _____.
Select one:
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 synapomorphy of mammals - Answers a. a shared ancestral character
Which of the following statements best describes the rationale for applying the principle of parsimony in
constructing phylogenetic trees?
Select one:
a. Parsimony allows the researcher to "root" the tree.
b. Similarity due to common ancestry should be more common than similarity due to convergent
evolution.
c. The molecular clock validates the principle of parsimony.
d. The outgroup roots the tree, allowing the principle of parsimony to be applied. - Answers b. Similarity
due to common ancestry should be more common than similarity due to convergent evolution.
Which of the following items is LEAST 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?
Select one:
a. number of genes
b. number of DNA base pairs
c. genome size
d. phenotypic complexity - Answers d. phenotypic complexity
The common ancestors of birds, crocodiles, and mammals were very early (stem) reptiles, which almost
certainly possessed three-chambered hearts (two atria, one ventricle). Modern lizards, snakes, and
turtles also have three-chambered hearts. Crocodiles, 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 _____.
Solutions Latest Update ( Graded A+)
The legless condition that is observed in several groups of living reptiles is the result of _____.
Select one:
a. their common ancestor having been legless
b. a shared adaptation to living in trees
c. several instances of the legless condition arising independently of each other
d. individual lizards adapting to a burrowing lifestyle during their lifetimes
e. all other reptiles having independently evolved legs; the legless condition is ancestral - Answers c.
several instances of the legless condition arising independently of each other
Concerning growth in genome size over evolutionary time, which of these is LEAST associated with the
others?
Select one:
a. orthologous genes
b. gene duplications
c. paralogous genes
d. gene families - Answers a. orthologous genes
gene family: A gene family is a set of several similar genes, formed by duplication of a single original
gene, and generally with similar biochemical functions
paralogous genes: homologous genes that occur within one species and have diverged after a
duplication event. Unlike orthologous genes, a paralogous gene is a new gene that holds a new function.
These genes arise during gene duplication where one copy of the gene receives a mutation that gives
rise to a new gene with a new function, though the function is often related to the role of the ancestral
gene.
orthologous genes: homologous genes that diverged after a speciation event. The genes generally
maintain a similar function to that of the ancestral gene in which they evolved from
, In a comparison of birds and mammals, having four limbs is _____.
Select one:
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 synapomorphy of mammals - Answers a. a shared ancestral character
Which of the following statements best describes the rationale for applying the principle of parsimony in
constructing phylogenetic trees?
Select one:
a. Parsimony allows the researcher to "root" the tree.
b. Similarity due to common ancestry should be more common than similarity due to convergent
evolution.
c. The molecular clock validates the principle of parsimony.
d. The outgroup roots the tree, allowing the principle of parsimony to be applied. - Answers b. Similarity
due to common ancestry should be more common than similarity due to convergent evolution.
Which of the following items is LEAST 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?
Select one:
a. number of genes
b. number of DNA base pairs
c. genome size
d. phenotypic complexity - Answers d. phenotypic complexity
The common ancestors of birds, crocodiles, and mammals were very early (stem) reptiles, which almost
certainly possessed three-chambered hearts (two atria, one ventricle). Modern lizards, snakes, and
turtles also have three-chambered hearts. Crocodiles, 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 _____.
