Evoution Exam 2 EOC questions

EOC questions

Which of the following is not a protein?

a. Histone.

b. Insulin.

c. Nucleotide.

d. Hemoglobin.

c. nucleotide

What role do histones play in eukaryotes?


1. Condensing the DNA and controlling the transcription of

genes.
2. Translating RNA and condensing the DNA.
3. Translating RNA and transcription of genes.
4. None of the above.

1. Condensing the DNA and controlling the transcription of

genes.

Which of the following is an important job of a hormone?

a. To splice alternative exons. \\n b. To alter expression of target genes.

c. To halt transcription of mRNA.

d. To induce translation of DNA.

b. To alter expression of target genes.

What is the name of DNA sequences that have lost their protein-coding ability?

a. Transposons.

b. Pseudogenes.

c. Introns.

d. Exons.

b. Pseudogenes.

Which of the following mutations does not affect gene expression?

a. Mutations to promoter regions.

b. Mutations to cis-regulatory regions.

c. Mutations that code for recessive alleles.

d. Mutations that code for hormones.

c. Mutations that code for recessive alleles.

Which of the following statements about genetic recombination is false?


1. Genetic recombination acts independently of independent assortment.
2. Genetic recombination occurs during the production of sperm.
3. Genetic recombination is relatively unimportant to the process of natural selection.
4. During meiosis, chromosomes can cross over and exchange segments of DNA so that chromosomes of gametes are different from the chromosomes of the parents.

3. Genetic recombination is relatively unimportant to the process of natural selection.

Which of these statements about the link between phenotypes and genotypes is not true?


1. The environment often affects how a phenotype will develop.
2. A single genotype may produce multiple phenotypes.
3. Human height is controlled by more than one gene.
4. Risk of Huntington’s disease is a quantitative (polygenic)

trait.

4. Risk of Huntington’s disease is a quantitative (polygenic) trait.

Which of the following is/are part of the environmental control of gene expression?

a. Signals from outside the body.

b. Signals from other genes within the cell.

c. Signals from other cells.

d. All of the above.

d. All of the above.

Which of the following is not true of DNA in eukaryotes?


1. It is regularly altered through horizontal gene transfer.
2. It is coiled tightly around a series of histone proteins.
3. It is reorganized into larger structures known as

chromosomes.
4. It is coiled to allow it to fit within a cell’s nucleus.

1. It is regularly altered through horizontal gene transfer.

If two individuals mate, one of them heterozygous at a locus and the other homozygous for a recessive allele at the same locus, what will be the outcome?


1. The offspring will be either heterozygous or homozygous for the recessive allele.
2. The offspring will be homozygous for the dominant allele, heterozygous, or homozygous for the recessive allele.
3. The offspring will not evolve because they will carry the same alleles as the parents.
4. The recessive allele eventually will become the dominant allele in the population.

1. The offspring will be either heterozygous or homozygous for the recessive allele.

The Hardy–Weinberg theorem demonstrates that


1. dominant alleles are more common than recessive alleles.


2. in the absence of outside forces, allele frequencies of a population will not change from one generation to the next.
3. a locus can have only one of two alleles.
4. evolution is occurring.

2. in the absence of outside forces, allele frequencies of a population will not change from one generation to the next.

3. Which population would be most likely to have allele frequencies in Hardy–Weinberg equilibrium?


1. A population in a rapidly changing environment.
2. A population where immigration is common.
3. A large population that currently is not evolving.
4. A population that cycles between a very large and a very

small number of individuals.

c. A large population that currently is not evolving.

Genetic drift

a. can cause the loss of an allele in a species.

b. happens faster in large populations than in small ones.

c. does not occur in large populations.

d. is a function of Hardy–Weinberg equilibrium.

a. can cause the loss of an allele in a species.

A genetic bottleneck in a population often results in

a. loss of alleles.

b. an increase in inbreeding.

c. an increase in genetic drift.

d. All of the above.

d. All of the above.

What do population geneticists mean when they refer to the fitness of an allele?


1. The ability of the allele to survive in a population.
2. The contribution of an allele to the strength and overall

health of a genotype.
3. The contribution of an allele to a genotype’s relative success

at producing new individuals.
4. Whether or not an allele is dominant.

3. The contribution of an allele to a genotype’s relative success at producing new individuals.

If a mutation produces a new deleterious recessive allele in a population, what is least likely to happen to the frequency of that allele?


1. It will remain at a low frequency within the population for a very long time.
2. Drift will determine whether it persists in the population.
3. The allele will be rare enough that it almost never occurs in a

homozygous state.
4. The allele will quickly be purged from the population by

selection.

4. The allele will quickly be purged from the population by selection.

If Cavalli-Sforza and colleagues had measured allele

frequencies as 0.869 for the A allele and 0.131 for the S allele, how many homozygous genotypes should they have expected to find? Would they have considered the population to be at equilibrium?


1. 9354 AA and 29 SS. No, they would not have considered the population to be at equilibrium.
2. 9354 AA and 211 SS. Yes, they would have considered the population to be close to equilibrium.
3. 9354 AA and 211 SS. No, they would not have considered the population to be at equilibrium.
4. 2811 AA and 2993 SS. No, they would not have considered the population to be at equilibrium.

3. 9354 AA and 211 SS. No, they would not have considered the population to be at equilibrium.

Which of these statements about inbreeding is false?


1. Inbreeding is not a mechanism of evolution.
2. Inbreeding can affect the fitness of individuals, but it does

not necessarily alter allele frequencies within a population.
3. Inbreeding increases the probability that two alleles at any

locus will be identical because of a shared common ancestor.
4. Inbreeding alters allele frequencies within a population but does not affect the fitness of individuals.

4\. Inbreeding alters allele frequencies within a population but does not affect the fitness of individuals.

What can measuring genetic distance, or tell

scientists about a group of organisms?

a. Whether groups have begun to diverge from each other.

b. Whether genes are under strong selection.

c. How barriers may be influencing gene flow.

d. All of the above

d. All of the above

Phenotypic traits often have a continuous distribution because they are

a. a result of dominance interactions.

b. not related to genotypes.

c. influenced only by the environment.

d. often polygenic.

d. often polygenic.

Which of these statements about narrow sense heritability (H^2) is true?


1. The numerator of narrow sense heritability includes additive, dominant, and epistatic gene effects.
2. The numerator of narrow sense heritability includes only the additive effects of alleles.
3. Narrow sense heritability includes only the epistatic effects of alleles.
4. Narrow sense heritability can be estimated by comparing quantitative trait loci among offspring using regression.

2. The numerator of narrow sense heritability includes only the additive effects of alleles.

The breeder’s equation incorporates two of the conditions Darwin identified that must be met for evolution by natural selection to take place. Which two?


1. Greater survival (S) and reproduction (R) of phenotypes with specific alleles.


2. Variation in phenotypic traits (R ) and heritability of

additive alleles (h^2)
3. Differences in phenotypes that influence the probability of survival or reproduction (S) and differences in phenotypic

traits that must be at least partially heritable (h^2)
4. Heritability of additive alleles (h^2) and the evolutionary response of the population (R).

3. Differences in phenotypes that influence the probability of survival or reproduction (S) and differences in phenotypic traits that must be at least partially heritable (h^2)

How can scientists determine what constitutes a quantitative trait locus?


1. They painstakingly examine the genotypes of hundreds of individuals and look for genes that are consistently similar.
2. They examine nucleotide sequences and count the repeated

segments that they feel are important.
3. They hybridize species and compare how genetic markers

recombine in the offspring.
4. They select for different traits in lineages of an organism,

cross-breed the lineages for two generations, and search for genetic markers that are correlated with expression of the trait.

4. They select for different traits in lineages of an organism, cross-breed the lineages for two generations, and search for genetic markers that are correlated with expression of the trait.

5. If the age of sexual maturation is a phenotypically plastic trait, what relationship(s) would you expect to find?


1. Genotypes differ in the age at which they reproduce.
2. Environmental conditions (such as nutrition) affect the age at

which individuals begin reproducing.
3. Body size affects the age at which different genotypes

reproduce.
4. All of the above.

b. Environmental conditions (such as nutrition) affect the age at which individuals begin reproducing.

Which of the following is an example of the process of evolution?


1. A population of snowshoe hares has a different frequency of alleles than the previous generation.
2. Trees drop their leaves in the fall.
3. A man becomes immune to a strain of virus that caused him

to have a cold when he was younger.
4. A female bird lays more eggs one season than she did the

three previous seasons combined.

1. A population of snowshoe hares has a different frequency of alleles than the previous generation.

The rate of adaptive evolution depends on

a. the strength of selection.

b. heritability of traits.

c. a and b.

d. phenotypes of organisms in natural populations.

c. a and b.

\-the strength of selection. \n -heritability of traits.

Which of the following is responsible for the heritability of a trait?


1. Influences on the genotype by additive environmental components.
2. The proportion of phenotypic variance that is due to genetic differences among individuals.
3. All of the genetic contributions to a trait’s phenotype.
4. Influences of the parental phenotype on the environment of the offspring.

3. The proportion of phenotypic variance that is due to genetic differences among individuals.

Genetic variance among individuals can be broken down into all of the following categories except


1. total variance in phenotypic trait in a population.
2. additive genetic variance.
3. variance due to dominance effects of alleles.
4. variance attributable to epistatic interactions among alleles at

various genetic loci.

1. total variance in phenotypic trait in a population.

Evolution happens when

a. there is a change in allele frequencies in a population.

b. there is a change in allele frequencies in a family.

c. there is selection of any kind.

d. All of the above.

a. there is a change in allele frequencies in a population.

Why is understanding coalescence important when developing molecular phylogenies?


1. Because scientists can’t know the true genealogy of a lineage without coalescing phylogenies to determine which is the most parsimonious.
2. Because scientists can sample only a limited portion of the history of any allele.
3. Because alleles that change over time are not valuable to developing phylogenies.
4. Because scientists can’t possibly determine the genealogy of a lineage from the limited samples available to them.

2. Because scientists can sample only a limited portion of the history of any allele.

Why don’t all gene trees reflect the phylogeny of species?


1. Because the branch lengths of a species tree are usually much longer on average than the coalescence times of the genes being analyzed.
2. Because coalescence of specific genes can occur before speciation events.
3. Because speciation events can sometimes be very rapid.
4. Both b and c.

4. Both b and c.

\-Because coalescence of specific genes can occur before speciation events.

\-Because speciation events can sometimes be very rapid.

Why might scientists use a statistical tool, such as Bayesian or maximum likelihood analyses, when reconstructing phylogenies?


1. Because otherwise scientists can easily misinterpret the outcome.
2. Because scientists can specify the parameters of a statistical model and test the capacity of the tool to produce comparable trees.
3. Because molecular data can provide both true and false signals of the branching history, and statistical tools can reveal important patterns in the changes that occurred.
4. Both 2 and 3.

4. Both 2 and 3.

\-Because scientists can specify the parameters of a statistical model and test the capacity of the tool to produce comparable trees.

\-Because molecular data can provide both true and false signals of the branching history, and statistical tools can reveal important patterns in the changes that occurred.

Molecular phylogenies indicate which of the following about HIV?


1. The same mutation evolved in three separate lineages of HIV; in each instance, the mutation improved the ability of the virus to infect humans.
2. HIV came from a monkey virus that was introduced into people by contaminated vaccinations.
3. HIV is a monophyletic strain of lentivirus that infects both humans and chimpanzees.
4. The common ancestor of simian immunodeficiency virus and human immunodeficiency virus came from horses.

1. The same mutation evolved in three separate lineages of HIV; in each instance, the mutation improved the ability of the virus to infect humans.

The theory of neutral evolution describes


1. the rate of mutation at a site that results from purifying

selection, regardless of the size of the population.
2. the rate of fixation of alleles at a site in the absence of

selection.
3. the competition between genetic drift and natural selection

within the genome.
4. Both 1 and 2.

2. the rate of fixation of alleles at a site in the absence of selection.

Which of these is a true statement about molecular clocks?


1. Molecular clocks use neutral theory to date events within a

phylogeny.
2. Molecular clocks can be calibrated using fossils of known

age.
3. Molecular clocks can be affected by the segments of DNA

being examined and relative sizes of the populations.
4. All of the above.

4. All of the above.

When dN > dS,


1. scientists would reject the null hypothesis of neutral

evolution because the number of replacement substitutions is

greater than expected.
2. scientists would accept the hypothesis that the population is

undergoing purifying selection because more replacement

mutations were found than expected.
3. scientists would reject the hypothesis that natural selection

took place millions of years ago and is no longer relevant.
4. scientists would accept the hypothesis that neutral evolution

took place millions of years ago.

1. scientists would reject the null hypothesis of neutral

evolution because the number of replacement substitutions is

greater than expected.

Which of the following is not true of coalescence? \n a. The timing of coalescence can depend on whether or not

alleles are under selection.


2. Positive selection can accelerate the rise in frequency in an allele, leading to a short coalescence.
3. Two alleles that experience little selection may coexist longer, and thus the farther back coalescence occurs.
4. In some instances, it is impossible to trace the genealogies of two homologous alleles in a population to a common ancestral allele, even if it is possible to trace their histories indefinitely.

4. In some instances, it is impossible to trace the genealogies of two homologous alleles in a population to a common ancestral allele, even if it is possible to trace their histories indefinitely.

Why do scientists use several genes when they examine the phylogenetic relationships among species?


1. Synonymous substitutions are more likely to be present in multiple genes.
2. The phylogeny of a single segment of DNA may be different from the phylogeny of the species that carry it.
3. Purifying selection can remove deleterious alleles from a population, and a single segment of DNA may be missing from one gene.
4. Scientists are aiming to increase their chances of finding microsatellites, which can be valuable genetic characters for comparing populations.

2. The phylogeny of a single segment of DNA may be different from the phylogeny of the species that carry it.

Which of the following is not true of the neutral theory of molecular evolution?


1. When neutral variation accumulates at a steady rate, the molecular signature generated is an unreliable measure to date events in the distant past.
2. The neutral theory of molecular evolution describes the pattern of nucleotide sequence evolution under the forces of mutation and random genetic drift in the absence of selection.
3. The neutral theory predicts that neutral mutations will yield nucleotide substitutions in a population at a rate equivalent to the rate of mutation, regardless of the size of population.
4. As long as mutation rates remain constant, neutral variation is expected to accumulate at a steady rate.

1. When neutral variation accumulates at a steady rate, the molecular signature generated is an unreliable measure to date events in the distant past.

How do novel traits arise?


1. Through an existing trait that reverts to a previous version.
2. Through mutation leading to new phenotypes.
3. Through genes that are inherited from the previous

generation.
4. Through a new combination of traits already existing in the

individual.

3. Through genes that are inherited from the previous generation.

What is a paralog?


1. A protein that has taken on a new function.
2. A protein that can have two different functions at once.
3. A gene that serves a similar function in a related species.
4. A gene that has taken on a new function through gene

duplication.

1. A protein that has taken on a new function.

What is an ortholog?


1. Two genes in two different species that serve the same

function and were inherited from a common ancestor.
2. Two genes in two different species that serve the same

function but were inherited from different ancestors.
3. Two genes in the same species that serve different functions

but were duplicated from the same original gene.
4. Two genes in the same species that serve the same function

but were inherited separately from different ancestors.

3. Two genes in the same species that serve different functions but were duplicated from the same original gene.

Which of the following processes did not lead to the evolution of snake venom?

a. Gene recruitment.

b. Natural selection.

c. Gene duplication.

d. Broad-sense heritability

d. Broad-sense heritability

What do you predict would happen to the hind legs of a fly if the gene Dpp were artificially overexpressed?

a. The legs would grow longer.

b. The legs would not grow as long.

c. The growth of the legs would be completely suppressed.

d. The early leg cells would be reabsorbed into the body.

d. The early leg cells would be reabsorbed into the body.

What role does Bmp2 play in the expression of bat wing phenotypes?


1. It is the only protein responsible for the shape of the wing.
2. It is one of two proteins that determine the shape of the

wing.
3. It is a regulatory gene that turns on many other genes.
4. It is turned on by the regulatory protein known as

calmodulin.

2. It is one of two proteins that determine the shape of the wing.

Which organism does not use crystallins in its eyes to focus light?

a. Humans.

b. Octopuses.

c. Fishes.

d. Ragworms.

a. Humans.

What is not an example of antagonistic pleiotropy?


1. Genes that create insect breathing tubes cause decreased

production of growth hormones.
2. Mutations that confer resistance to Bacillus thuringiensis

(Bt) also make insects more vulnerable to natural plant defensive chemical
3. Developmental genes that code for greater or fewer than seven cervical vertebrae have negative fitness costs.
4. Carriers of a recessive gene for cystic fibrosis have greater resistance to tuberculosis.

1. Genes that create insect breathing tubes cause decreased

production of growth hormones.

Why do giraffes have a recurrent laryngeal nerve that is 19 feet longer than the shortest route possible?


1. Their ancestors were fishes and did not have a larynx.
2. The route of that nerve was inherited from their ancestors.
3. The nerve makes more connections to their lungs than in

their ancestors.
4. The route that the nerve takes is the result of random

processes.

4. The route that the nerve takes is the result of random processes.

What do you predict would happen if you inserted a Pax-6 gene from a mouse into the genome of an octopus?


1. No eyes would develop in the octopus.
2. The normal two eyes would develop, but they would not

work.
3. Extra eyes would develop, but with mouse crystallins.
4. Extra eyes would develop, but with octopus crystallins.

3. Extra eyes would develop, but with mouse crystallins.