EXAM I – Study Guide

Which of the following statements about biological evolution is FALSE?

A. Species change over time.
B. Natural selection produces changes in species.
C. Individuals in a population evolve.
D. Different species may share a common ancestor

C. Individuals in a population evolve.

Which of the following descriptions of a gene pool shown below is CORRECT?

A. Population size = 15
B. Number of genes = 2
C. Frequency of X1 = 0.80
D. Size of gene pool = 30
E. Frequency of X1X3 = 0.10

E. Frequency of X1X3=0.10

Mistakes in the replication of DNA

A. often occur.
B. are always repaired.
C. provide genetic variation.
D. are not transmitted to offspring.
E. are always deleterious to an organism

C. Provide genetic variation

Which of the following phenomena is not an evolutionary mechanism?

A) Mutation
B) Gene flow
C) Genetic drift
D) Random mating
E) Natural selection

D. Random mating

Genotype frequencies may be altered by

A) genetic drift.
B) the founder effect.
C) gene flow.
D) nonrandom mating.
E) All of the above

E. All of the above

6. Artificial selection for certain traits in Brassica oleracea (European wild mustard)

A) produced a single new species.
B) generated new populations with identical genetic makeup.
C) gave rise to plants that are quite different in appearance due to the introduction of
foreign DNA.
D) gave rise to plants that are quite different in appearance by virtue of the genetic
variation inherent in the mustard plant.
E) gave rise to plants that are quite different in appearance due to low variability in
the gene pool of the mustard plant.

D. gave rise to plants that are quite different in appearance by virtue of the genetic variation inherent in the mustard plant.

7. Which of the following agents of evolution ADAPTS POPULATIONS to their environments?

A) Mutation
B) Natural selection
C) Nonrandom mating
D) Gene flow
E) Genetic drift

B. Natural Selection

8. Why does genetic drift affect small populations more than large ones?

A) Genetic drift drives the extinction of many species.
B) Random changes in allele frequencies from one generation to the next can produce
large changes in allele frequencies over time, allowing harmful alleles to increase
in frequency.
C) Genetic drift in fact affects larger populations more than smaller ones.
D) Genetic drift drives the movement of many species worldwide causing populations
size to reduce even further.
E) Genetic drift affects all populations equally.

B. Random changes in allele frequencies from one generation to the next can produce

9. The frequency of alleles for a given gene locus with two alleles (A and a) in two
subpopulations of the same species

A) is necessarily the same in both populations.

B) can vary from p + q = 1.

C) is N = NAA + NAa + Naa (where N is the number of individuals in the populations) in
both populations.

D) is always lower for the heterozygote.

E) is always lower for the homozygotes.

C. is N = NAA + NAa + Naa (where N is the number of individuals in the populations) in both populations.

10. The frequency of one allele for a given gene locus with two alleles (A and a) in a
population is known. Assume Hardy-Weinberg conditions hold true. Which of the
following statements is FALSE?

A) The frequency of heterozygotes is given by (p + q)/N, where N is the # of
individuals in the population.

B) There is sufficient information given to calculate the frequency of heterozygotes
(Aa).

C) The frequency of a is given by 1 – p.

D) The frequency of A is given by 1 – q.

E) The frequency of a is dependent on that of A.

A. The frequency of heterzygotes is given by (p+q)/N, where N is the # of individuals in the population.

11. Allele frequencies measure the _______ of a population, whereas _______ show(s) how
it is distributed among its members.

A) genetic structure; genotype frequencies

B) polymorphisms; genotype frequencies

C) genetic variation; genotype frequencies

D) genotype frequencies; genetic structure

E) genotype frequencies; genetic variation

C. Genetic Variation; Genotype Frequencies

12. The Hardy-Weinberg equilibrium is not applicable under which of the following
conditions?

A) Random mating
B) Infinite population size
C) No gene flow
D) Asexual reproduction
E) No mutations

D. Asexual reproduction

13. Which of the following statements about deviations from the Hardy-Weinberg
equilibrium in populations is false?

A) Deviations are very rare.

B) They suggest that mechanisms exist in nature that can change the frequency of
alleles.

C) They provide evidence for evolution.

D) They can help in the identification of the mechanisms of evolution.

E) All of the above are true; none is false.

A. Deviations are very rare & E. All of the above are TRUE.

14. Which of the following statements about selection is TRUE ?

A) Disruptive selection is the only type of selection to produce a bimodal pattern.

B) Stabilizing selection increases variation.

C) In directional selection, individuals close to the mean have the highest fitness.

D) Disruptive selection favors individuals close to the mean.

E) Stabilizing selection is the only type of selection that acts on quantitative variation.

A. Disruptive selection is the only type of selection to produce a bimodal pattern.

<b>15</b> _______ selection operates if individuals within a population with the smallest and
largest body sizes have fewer offspring than those of average body size.

A) Stabilizing
B) Destabilizing
C) Sexual
D) Directional
E) Disruptive

A. Stabilizing B. Destabilizing

<b>16</b> Which of the following statements about synonymous mutations is true?

A) They change the amino acid composition of the protein.

B) They do not change the phenotype.

C) They will affect the structure of the protein.

D) They will likely change the activity of the protein.

E) They will likely be lethal.

A. They will change the amino acid composition of the protein.

17. Nonsynonymous substitutions in a gene coding for a protein

A) result in the replacement of an amino acid in the protein.

B) may be neutral.

C) may be deleterious.

D) may be beneficial.

E) All of the above

E. All of the above.

18. A NEUTRAL MUTATION

A) becomes fixed in a large populations more rapidly than in large ones.

B) is subject to strong selection.

C) confers a selective advantage to an organism.

D) is fixed in a population at a rate equal to the mutation rate.

E) confers a selective disadvantage to the organism.

D. is fixed in a population at a rate equal to the mutation rate

19. Comparisons of the genes that code for lysozyme and the amino acid sequence of the
enzyme from a number of organisms revealed that

A) the rate of nonsynonymous mutations is higher than that of synonymous mutations.

B) a common recent ancestor is necessary for organisms to develop very similar
adaptations.

C) bovine (cattle) lysozyme was exactly the same as langur lysozyme.

D) the # of changes in lysozyme uniquely shared by cattle, langur, and the
hoatzin was high.

E) none of the changes in lysozyme were adaptive.

D. The # of changes in lysozyme was uniquely shared by cattle, langur, and the hoatzin was high.

20. A eukaryotic organism’s
genome

A) is defined as the genes that code for proteins.

B) is all of the DNA in the nucleus.

C) is all of the genes in the organism.

D) is all of the genes as well as noncoding regions of DNA.

E) excludes DNA in organelles.

C. is all of the genes in the organism.

21. Which of the following
statements about the genomes of organisms is FALSE?

A) Most of the DNA in a bacterium codes for either RNA or protein.

B) The total size of the genome of eukaryotes varies little from organism to organism.

C) There is some correlation between genome size and complexity of the organism.

D) Pseudogenes may play a role in evolution.

E) Noncoding regions of the DNA have higher mutation rates than coding regions.

B. The total size of the genome of eukaryotes varies little from organism to organism

22. SEXUAL RECOMBINATION

A) increases the overall reproductive rate.

B) can result in the elimination of harmful mutations.

C) decreases the variety of genetic combinations.

D) changes the frequency of alleles in a population.

E) has no influence on evolution.

B. can result in the elimination of harmful mutations

23. GENE DUPLICATION can

A) occur by duplication of an entire diploid genome.

B) result in the formation of pseudogenes.

C) result in genes that are lost from the genome.

D) lead to the evolution of genes that code for proteins with new functions.

E) All of the above

E. All of the above.

24. Gene families are groups of _______ genes that arose by _______ and _______.

A) homologous; speciation; sequence evolution

B) heterologous; gene duplication; sequence evolution

C) homologous; gene duplication; genetic drift

D) heterologous; speciation; genetic drift

E) homologous; gene duplication; sequence evolution

E. Homologous; Gene Duplication; Sequence Evolution

25. IN VITRO evolution

A) refers to the use of bacteria to study evolution.

B) refers to the effects of genes manipulated in vitro on evolution.

C) is the synthesis of macromolecules with particular properties based on principles of
molecular evolution.

D) uses natural selection.

E) only works for proteins.

C. is the synthesis of macromolecules with particular properties based on principles of molecular evolution.

26. The _______ of a
phylogenetic tree represents the common ancestor, the _______
represent places where lineages diverge, and the _______ axis represents time. Assume
that the tree is oriented as described in the textbook.

A) Node; Roots; Horizontal

B) Root; Nodes; Horizontal

C) Root; Nodes; Vertical

D) Node; Branches; Vertical

E) Root; Branches; Vertical

B. Roots, Nodes, Horizontal

~27~. Which of the following phylogenies are equivalent?

A) A and B

B) A and C

C) B and C

D) They are all the same.

E) They are all different.

A. A and B

28. A _______ is any group of organisms we name, whereas a _______ is any _______ that
consists of all the evolutionary descendents of a common ancestor.

A) Taxon; Clade; Taxon

B) Clade; Taxon; Sister clade

C) Taxon; Sister clade; Clade

D) Taxon; Clade; Sister clade

E) Clade; Sister Clade; Taxon

A. Taxon, Clade, Taxon

~29~. All clades are subsets of larger clades. The most inclusive clade on the following
diagram is _______; the least inclusive clade includes the _______.

A) mammals; mouse

B) tetrapods; salamander

C) amniotes; lizard

D) vertebrates; chimpanzee

E) mammals; lamprey

D. vertebrates; chimpanzee

30. Which of the following statements about traits is FALSE?

A) A trait may be considered ancestral or derived, depending on the point of reference.

B) Synapomorphies are shared ancestral traits.

C) Derived traits differ from their ancestral forms.

D) Homoplastic traits can arise by convergent evolution.

E) Traits may be lost by evolutionary reversal.

B. Synapomorphies are shared ancestral traits.

32. Phylogenetic trees

A) are rarely modified once constructed.

B) maximize the number of homoplasies.

C) are constructed from just one source of data.

D) are generally easy to construct.

E) are constructed using the parsimony principle.

E. are constructed using the parsimony principle.

33. Refer to the phylogenetic tree shown in below. Which of the following statements is
true?

A) The tree is polyphyletic.

B) The tree is based on homoplastic traits.

C) The mouse is the sister species to the chimpanzee.

D) The lizard is more closely related to the salamander than to the crocodile.

E) The lamprey is the outgroup because it is not a vertebrate.

C. The mouse is the sister species to the chimpanzee.

34. Which of the following traits is likely to be unsuitable for phylogenetic analysis?

A) Learned behavior
B) Morphology
C) DNA sequences
D) Protein sequences
E) Development

A. Learned behavior

35. A sea squirt is thought to be more closely related to vertebrates than once thought
because

A) both the adult and larval forms of the sea squirt have a notochord.

B) adult sea squirts have notochords.

C) sea squirt larvae have a vertebral column.

D) both vertebrate embryos and sea squirt larvae have notochords.

E) adult frogs have notochords.

D. both vertebrate embryos and sea squirt larvae have notochords.

~36~. The phylogenetic tree shown in below is based on

A) amino acid sequences of viral proteins.

B) DNA sequences of the host.

C) DNA sequences of the ancestral virus.

D) DNA sequences of viruses at the nodes.

E) DNA sequences of just the viruses at the tips of the tree.

E. DNA sequences of just the viruses at the tips of the tree.

37. Phylogenetic analysis of a section of the plant genus Leptosiphon

A) was based on the sequences of mitochondrial DNA.

B) revealed that L. "bicolor" is actually three distinct lineages.

C) showed that the Leptosiphon group is synapomorphic.

D) showed that the Leptosiphon group has a homoplastic trait.

E) revealed that an ancestral species of the Leptosiphon group was likely to be
self-compatible.

B. revealed that L. "bicolor" is actually three distinct lineages.

~38~. Refer to the diagram below showing a polygenetic tree of immunodeficiency viruses.
Which of the following statements is FALSE?

A) HIV viruses evolved from simian immunodeficiency virus (SIV).

B) HIV-1 and HIV-2 are more closely related to each other than to any of the simian
immunodeficiency viruses.

C) There are two different HIV strains.

D) SIVcpz could be considered an outgroup for the clade of SIV that is found in
sun-tailed and African green monkeys.

E) SIVsm and HIV-2 are sister clades.

B. HIV-1 and HIV-2 are more closely related to each other than to any of the simian immunodeficiency viruses.

39. Phylogenetic analyses of opsin pigments have allowed scientists to infer that ancestral
archosaurs

A) could be brought back to life.
B) had a pre-existing sensory bias.
C) had yellow eyes.
D) may have been nocturnal.
E) could not see blue.

D. may have been nocturnal

40. MOLECULAR CLOCKS

A) would not keep the same time for all genes.

B) must be calibrated.

C) work best for a gene in closely related species.

D) assume that the rate of change of a gene is relatively constant.

E) All of the above

E. All of the above.

41. In the classification system devised by Linnaeus, the names of _______ of plants end
with the suffix _______, whereas those of animals end with _______.

A) classes; -idae; -aceae

B) families; -aceae; -idae

C) orders; -idae; -aceae

D) families; -idae; -aceae

E) classes; -aceae; -idae

B. families; -aceae; -idae

42. Which of the following statements about biological classification is FALSE?

A) Taxonomists use biological classification to show evolutionary relationships
among organisms.

B) Separate rules for classification were established by botanists and zoologists.

C) The same binomial name may be given to two different organisms as long as they
are in different phyla.

D) Classifications should be monophyletic.

E) A monophyletic group may be removed from a phylogenetic tree with a single
"cut."

C. The same binomial name may be given to two different organisms as long as they are in different phyla.

43. A taxon that contains organisms that do not share a common ancestor is called

A) a clade.
B) monophyletic.
C) polyphyletic.
D) homologous.
E) homoplastic

C. polyphyletic.

<b>31</b>. The bones in the wings of birds and bats are _______ because they derived from a
_______ ancestor, while the wings are _______ traits.

A) Homologs; Common; Nonhomologous

B) Homologous; Common; Homoplastic

C) Homoplasies; Different; Homologous

D) Homologous; Different; Homoplastic

E) Homologs; Common; Homologous

B or A

~44~. Based on the figure below, which of the following taxa are Monophyletic?

A) Blue
B) Green
C) Red
D) Yellow
E) Both a and c

E. Both a and c

45. A group that consists of all the evolutionary descendants of a common ancestor is called
a(n)

A) grade.
B) taxon.
C) homology.
D) ingroup.
E) clade.

E. clade.

46. Which of the following sources of molecular data would be most helpful for a study of
the evolutionary relationships of closely related animal species?

A) Chloroplast DNA

B) Mitochondrial DNA

C) The amino acid sequences of
a protein found in all animals, such as cytochrome c

D) Ribosomal RNA sequences

E) Both b and d

B. Mitochondrial DNA

47. The most important attribute of a biological classification scheme is that it

A) avoids the ambiguity created by the use of common names.

B) reflects the evolutionary relationships among organisms.

C) helps us organize our knowledge about organisms and their traits.

D) improves our ability to make predictions about the morphology and behavior of
organisms.

E) groups together organisms with similar traits.

B. reflects the evolutionary relationships among organisms

48. Which of the following lists of taxonomic categories represents the correct ordering,
from most inclusive to least inclusive?

A) Phylum, order, family, genus

B) Class, phylum, order, species

C) Order, class, family, genus

D) Family, order, class, kingdom

E) Kingdom, class, species,
genus

A. Phylum, Order, Family, Genus

49. Which of the following statements describes a purpose for which biologists use
phylogenetic trees?

A) Phylogenetic trees are helpful in determining when and where an infectious
organism once found in other animals first entered human populations.

B) Phylogenetic trees are useful for determining how many times a particular trait may
have evolved independently within a lineage.

C) Phylogenetic trees can be used to reconstruct ancestral traits.

D) Phylogenetic trees can be used in conjunction with molecular clocks to estimate the
timing of evolutionary events.

E) All of the above

E. All of the above.

50. Refer to the diagram below showing a phylogenic tree. If birds are not considered
reptiles, but reptiles include turtles, lizards and crocodiles, the group called "Reptiles"
would be

A) a clade.

B) monophyletic.

C) polyphyletic.

D) paraphyletic.

E) homoplastic.

C. polyphyletic