EVOLUTION EXAM 2
You are studying a population of snails and you observe that there are two alleles for shell strength. Allele 1 codes for thin shells and is dominant over allele 2, which codes for thick shells. Allele 2 is at a frequency of 70% of the population, what should be the frequency of allele 1 homozygotes?
0.09
You are studying a population of palm trees and you observe that there are two alleles for frond shape. Allele 1 codes for rounder fronds and allele 2 codes for squarer fronds. Allele 2 is at a frequency of 70% of the population. What should be the frequency of allele 1?
0.30
You are studying a population of pangolins and you observe that there are two alleles for scute shape. Allele 1 codes for round scutes and allele 2 codes for squarer scutes. Allele 2 is at a frequency of 60% of the population. What should be the frequency of allele 1?
0.40
You are studying a population of milkweeds and you find the following allele frequencies: f(A1A1) = 0.36 f(A1A2) = 0.48 f(A2A2) = 0.16 If the fitness of the heterozygote (w12) is 0.9 and the average fitness of the population is 0.916, what do we expect the new frequency of the heterozygote genotype to be in the next generation?
0.47
You are studying a population of black rats and you find the following allele frequencies: f(A1A1) = 0.23 f(A1A2) = 0.50 f(A2A2) = 0.27 What is the frequency of the A1 allele in your population?
0.48
You are studying a population of sunflowers and you observe that there are two alleles for stem length. Allele 1 codes for fat stems and is dominant over allele 2, which codes for thin stems. Allele 2 is at a frequency of 30% of the population, what should be the frequency of allele 1 homozygotes?
0.49
You are studying a population of sunflowers and you observe that there are two alleles for stem length. Allele 1 codes for fat stems and is dominant over allele 2, which codes for thin stems. Allele 2 is at a frequency of 20% of the population, what should be the frequency of allele 1 homozygotes?
0.64
You are studying a population of cuttlefish and you find the following allele frequencies: f(A1A1) = 0.42 f(A1A2) = 0.46 f(A2A2) = 0.12 What is the frequency of the A1 allele in your population?
0.65
You are studying a population of rattlesnakes and you find the following allele frequencies: f(A1A1) = 0.72 f(A1A2) = 0.26 f(A2A2) = 0.02 What is the frequency of the A1 allele in your population?
0.85
You are studying forget-me-nots and you discover that there are two flower colors (blue and white) that follow Mendelian inheritance patterns. Breeding data suggest that the blue allele is dominant to the white allele, and when you examine 200 flowers from your wild population you find 162 plants with white flowers. Based on this, what would you expect to be the frequency of the blue allele?
10%
You are studying forget-me-nots and you discover that there are two flower colors (blue and white) that follow Mendelian inheritance patterns. Breeding data suggest that the blue allele is dominant to the white allele, and when you examine 200 flowers from your wild population you find 98 plants with white flowers. Based on this, what would you expect to be the frequency of the blue allele?
30%
You are studying a population of cactus and you discover that there are two spine lengths (short and long) that follow Mendelian inheritance patterns. Breeding data suggest that the long-spine allele (LS) is dominant to the short-spine allele (SS), and when you examine plants from your wild population you find 38 plants (out of 200) with the long-spine phenotype. Based on this, what would you expect to be the frequency of the SS allele?
90%
Which of the following events would have the highest selection differential (S)?
A population of monkeys where the parental generation has a mean hind foot length of 10.1 cm and the members who reproduce have a mean hind foot length of 11.8 cm
Which of the following are assumptions of the Hardy-Weinberg theorem?
All possible genotypes at a locus will be equally likely to survive and reproduce. Alleles will not enter or leave a population through migration. Mutation leading to new alleles will not occur.
You are studying populations of bighorn sheep and coyotes across the landscape. Based on their biology, which species would you expect to show the greatest genetic divergence among populations?
Bighorn sheep should show higher Fst values than coyotes.
How do broad and narrow sense heritability differ?
Broad sense heritability is a measure of the proportion of variation that is due to any genetic component Narrow sense heritability is the component of variance that causes organisms to look like their parents
How does parallel evolution differ from deep homology?
Deep homology occurs when the growth and development to traits in different lineages arise the same underlying evolutionary mechanism. Deep homology can help explain cases of parallel evolution.
Which of the following accurately describes the signal cascade in a typical gene regulatory network:
Environmental signal triggers transcription factor; transcription factor binds cis¬-regulatory element; protein coding gene activated
Promiscuous proteins and gene recruitment differ because:
Gene recruitment occurs when a gene or network becomes co-opted for a different function as a result of a mutation.
Why is Hardy-Weinberg a null hypothesis for evolutionary studies?
Hardy-Weinberg provides expected frequencies for alleles in the absence of evolutionary mechanisms.
When Peter Buri bred thousands of fruit flies in the 1950s, what was he trying to accomplish?
He was testing the effects of genetic drift on eye color?
You are studying populations of lynx and brown bears across the landscape. Based on their biology, which species would you expect to show the greatest genetic divergence among populations?
Lynx should show lower Fst values than brown bears.
Which of the following is true about the effects of drift and selection on populations of different sizes?
Natural selection is more effective in small populations, because it takes less selection to fix to a beneficial allele
Is inbedding by itself a mechanism of evolution?
No. Inbreeding rearranges alleles so that homozygotes for rare recessive alleles become more common. No. Inbreeding does not change the frequency of alleles in a population.
Orthologs differ from paralogs because:
Paralogs are homologous genes that arise from gene duplication. Together they form a gene family. Orthologs are homologous genes separated by a speciation event (as opposed to homologous gene, produced by gene duplication, that are both possessed by the same species)>
You are interested in the conservation of American burying beetles and you uncover the following Fst measurements. Based on these results, which population should you focus most of your efforts for increasing connectivity?
Population 2
What the figure above showing with respect to the origin and fate of new mutations?
Some new beneficial mutations are fixed by selection, but other alleles may arise but later lost
When population geneticists say that sexually reproducing organisms are mating at random what does this mean?
That, for a focal genetic locus, the probability of fertilization of one gamete by another will not vary depending on which allele is carried by the gamete.
What is p^2?
The frequency of the genotypes. The probability that an offspring will receive a p allele from one parent multiplied by the probability they will receive the same allele from the other parent.
Which of the following is true about rare alleles?
They are almost always carried in a heterozygous state.
What do population geneticists mean when they refer to assuming a population is infinitely large?
They are assuming there is no change due to genetic drift.
What do population geneticists mean when they assume every genotype is equally likely to survive and reproduce?
They are assuming there is no natural selection.
Based on sexual selection, male signals are more likely to be honest when:
They are costly to produce. They are condition-dependent.
How do scientists test the hypothesis that insect size is constrained by access to oxygen?
They compared the sizes of insects in the fossil record when oxygen concentrations were higher to when oxygen concentrations were lower.
When would we consider an allele to be selectively neutral?
When it has no effect on the fitness of it's bearer
A mutation introduces a new allele into a population. If this allele is under positive selection, in which case would it move the fastest to reach 100% frequency in the population?
When the allele is additive
A mutation introduces a new allele into a population. If this allele is under positive selection, in which case would it be unable to reach 100% frequency in the population?
When the allele is dominant
What occurs during a founder effect?
a new population is founded by a small number of individuals random sampling of alleles leads to a loss in genetic diversity
You are studying beak development in Darwin's finches and you find that Bmp4 expression in the bird you are looking at has increased but calmodulin has decreased. Based on this you can conclude that the bird will have:
a wide, deep, and short beak
What do p and q represent?
allele frequencies
You are studying a population of wolves and you find 13% of the alleles at a specific coat color locus in your population are recessive. If you were to consider this information in the context of the Hardy-Weinberg theorm, the 13% you have been given represents:
allele frequency
In scarlet kingsnakes alleles that lead to a coloration pattern similar to coral snakes:
are advantageous where kingsnakes and coral snakes co-occur
Which of the following was necessary for the evolution of beak size on Daphne Major:
beak size had to be at least partially determined by the additive effects of alleles characteristics of the average seed had to change from year to year
Based on graph 8.24, what type of selection has hunting imposed on horn length in bighorn sheep populations:
directional
Based on the outcome of previous experiments, if you moved guppies from predator free streams to predator rich streams for many generations, which of the following changes would you expect:
females would produce more offspring
Florida panthers were once common but during the 20th century their numbers fell to as few as 6 individuals. Which of the following processes had likely affected them as a result of this history?
genetic bottleneck
An analysis of allelic diversity indicates that maize had lost around 30% diversity by 4400 years ago. How do we explain this loss of diversity?
genetic bottleneck, strong artificial selection, and genetic drift
Which of these statements is/are not true about genetic drift?
genetic drift happens faster in large populations than in small ones genetic drift does not occur in large populations
The red queen hypothesis proposes that sex to is beneficial because:
genetic variation in offspring generated through sex is advantageous in a changing environment
You're working on a project on sexual selection in stickleback and you observe that female stickleback seem to prefer males with brighter red coloration on their bellies. You do some additional work to look at the males themselves, and you find the results shown below. Based upon these results, you can conclude that females who choose redder males are demonstrating:
good genes
Which of the scenarios below will produce the largest response to selection within a population?
h2= 0.9 s=0.6
You learn from a friend that birth weight in humans is the product of stabilizing selection. Based upon this information you can conclude:
humans populations are not evolving with respect to baby size
When population geneticists refer to a fixed allele, what do they mean?
it is the only allele remaining in a population after all of the alternatives have disappeared
Which is the most likely reason that lactose tolerance alleles selectively swept through certain human populations?
lactose intolerance had a large effect on survival
Which statement(s) helps explain why male pipefish produce very few sperm:
male fitness is limited mostly by the number of eggs they can care for
Which statement(s) helps explain why male little brown bats produce a lot of sperm:
male fitness is limited mostly by the number of eggs they can fertilize
If extrinsic mortality is high:
organisms should age more rapidly than if extrinsic mortality was low
You are studying a population of elk and you find 2% of the population carries a phenotype that is coded for by a dominant allele. If you were to consider this information in the context of the Hardy-Weinberg theorm, the 2% you have been given represents:
p^2 + 2pq
You are studying a population of wolves and you find 5% of the alleles at a specific coat color locus in your population are recessive. If you were to consider this information in the context of the Hardy-Weinberg theorm, the 5% you have been given represents:
q
You are studying a population of armadillos and you find 34% of the population is homozygous for a recessive allele. If you were to consider this information in the context of the Hardy-Weinberg theorm, the 34% you have been given represents:
q^2
You are studying a population of wolves and you find 13% of the alleles at a specific coat color locus in your population are recessive. If you were to consider this information in the context of the Hardy-Weinberg theorm, the 13% you have been given represents:
q^2
Genetic Drift:
reduces genetic variation within a population can lead to divergence between populations
You are studying aging in two species of fish. You bring them into a common laboratory environment free from factors causing extrinsic mortality and find that species A lives twice as long as species B. Based on the evolutionary theory of aging, you would predict that:
species B has higher extrinsic mortality in its natural habitat than species A
Which of the following types of selection will result in members of a population being more phenotypically similar to each other than in the starting population?
stabilizing selection
The arbitrary choice hypothesis requires:
that the male trait that the female prefers is heritable
Which of the following scenarios would provide evidence that an allele has experienced a selective sweep in the recent past?
the allele is at high frequency and linkage disequilibrium with surrounding loci is high
Which of the following scenarios would provide evidence that an allele has experienced a selective sweep in the recent past?
the allele is at high frequency and linkage disequilibrium with surrounding loco is high
What is phenotypic plasticity?
the capacity for a genotype to express more than one phenotype, depending on the environment
Which of the following statements about venom evolution is accurate?
the earliest venoms evolved before fangs and other parts of the venom delivery system
You are reading Science News and learn about a new gene that has been discovered in the placenta which is responsible for diverting more nutrients to the developing fetus in the individuals who carry it. Based on what you've learned on genomic imprinting, you predict:
the father's copy is turned on; the mother's copy is turned off
Which of the following questions would be studied with quantitative genetics?
the genetics of break length of Darwin's finches
What does the image tell you about the probability of losing an allele during a genetic bottleneck?
the lower the initial frequency of the allele the more likely it is to be lost the larger the population size during a bottleneck the less likely it is for an allele to be lost
The greater the narrow sense heritability:
the more offspring should resemble it's parents
Which of the following statements accurately describes Hox genes:
their expression gives positional information to other genes they are transcription factors
Which of the following is true of QTL association studies:
they rely on recombination to create a wide range of phenotypic variation
You are studying developmental biology in vertebrates and you identify that a particular set of tissues has HoxB5, HoxC8, and HoxC6 expressed. Based upon this information, you conclude that this region will form into:
thoracic vertebrae