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Test 1
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Question 1 Your answer is CORRECT. According to Darwin, which of the following is a requirement for the process of evolution by natural selection? a) Homologous traits b) Neutral mutations c) Uniformitarianism d) Nonrandom survival or reproduction e) Populations that differ in size Question 2 Your answer is CORRECT. Biological evolution is best defined as: a) Selection on individuals for the good of the species. b) A progression from lower to higher organisms driven by natural selection. c) Random processes leading to adaptation. d) Change in the heritable traits of populations over multiple generations. e) Individual variation resulting from natural selection. Question 3 Your answer is CORRECT. The graphs below show the change in allele frequency over 500 generations of natural selection. The two graphs represent two populations experiencing two different selective scenarios. Which statement best describes the difference between the two populations?
a) The selective coefficient is smaller in the population on the left than in the population on the right. b) The graph on the left shows an unstable equilibrium; the graph on the right shows a stable equilibrium. c) The graph on the left shows genetic drift; the graph on the right shows natural selection. d) Selection is favoring a beneficial recessive allele in the population on the left and a beneficial dominant allele in the population on the right. e) The graph on the left shows heterozygote advantage; the graph on the right shows a beneficial dominant allele. Question 4 Your answer is CORRECT. Based on the phylogeny of vertebrates shown below: a) Amphibians have amniotic eggs. b) Bony skeleton is a synapomorphy of sharks and ray-finned fish. c) Primates and rodents and rabbits form a monophyletic group. d) Four limbs is a homoplasious trait of amphibians and crocodiles. e) Amphibians are more closely related to ray-finned fish than they are to crocodiles. Question 5
b) We cannot reject the hypothesis that this population is in Hardy-Weinberg equilibrium because chi-squared is larger than the critical value. c) We cannot reject the hypothesis that population is in Hardy-Weinberg equilibrium at this locus because p is greater than 0.05. d) We cannot determine from the given data if the population is in Hardy-Weinberg equilibrium. e) We can reject the hypothesis that this population is in Hardy-Weinberg equilibrium at this locus at p less than 0.05. Question 8 Your answer is CORRECT. When a population reaches a stable equilibrium at a locus: a) Allele frequencies will continue to increase. b) Any perturbation away from the current allele frequencies will result in a return to the same frequencies. c) Allele frequencies will be maintained at p=0.5 and q = 0.5. d) Perturbations to the allele frequencies will lead to loss of one allele and fixation of the other. e) There will be more than one allele in the population. Question 9 Your answer is CORRECT. A scientist places lizards on an island and returns later to find all the lizards gone. a) This provides evidence of biological change over time because the lizards went extinct. b) This provides evidence of biological change over time because it was an experiment. c) This provides no evidence for biological change over time because the lizards could not adapt. d) This demonstrates that biological change over time occurs, but only very slowly. e) This does not provide evidence of biological change over time. Question 10 Your answer is CORRECT. Which of the following do NOT provide evidence that morphological evolution often occurs through changes in the size of one trait relative to the size of the body: a) comparing the size of homologous morphological structures among species b) comparing the morphology within groups of domesticated animals such as dogs or pigeons. c) the observation that insects have larger limbs relative to their bodies than do tetrapods. d) evolution of relative limb size to match habitat type in lizards e) variation in relative beak size in Darwin's finches across years. Question 11 Your answer is CORRECT.
Paralogs are homologous genes that arise by gene duplication. In the phylogeny below, which pair of genes are paralogs? a) None of the genes shown on the phylogeny are paralogs b) Human gene A2 and Chimp gene A c) Mouse gene A and Rat gene A d) Human gene A1 and Chimp gene A e) Human gene A1 and Human gene A Question 12 Your answer is CORRECT. Pea aphids are found in two colors, pink and green, determined by a single locus, where green is dominant to pink. In one population of aphids, you find 328 pink aphids out of 750. If the population is in Hardy-Weinberg equilibrium, how many of the green aphids are homozygotes? a) 34 b) 117 c) 349 d) 11 e) 86 Question 13 Your answer is CORRECT. In a population of chimpanzees, you find high infection rates of a highly virulent virus. Resistance to the virus is conferred by an allele with incomplete dominance (semi-dominance). Homozygotes are completely resistant, are expected to live a long life and have, on average, 8 offspring. Approximately 30% of the heterozygotes will die from the infection before reaching maturity; those that do survive will have 6 offspring on average. Only 10% of homozygotes for the susceptible allele will survive to maturity and those that survive will have only 1 offspring on average. What are the relative fitnesses of the three genotypes? a) Resistant homozygote: 1; heterozygote: 0.1125; susceptible homozygote: 0.
a) The graph on the top shows a smaller population size. b) The graph on the top shows a higher rate of mutation. c) The graph on the bottom shows a larger selective coefficient. d) The graph on the bottom shows heterozygote advantage. e) The difference between the graphs is just due to chance. Question 16 Your answer is CORRECT. Imagine a deleterious recessive allele (a) that is caused by insertion of a transposable element into a gene. Due to high rates of transposition, a new version of this allele is created from the beneficial allele once every 100 generations (mutation rate=1/100). If individuals who are homozygous for this allele suffer a 30% reduction in fitness, what are the equilibrium frequencies of the 3 genotypes? a) AA: 0.817; Aa: 0.183; aa: 0 b) AA: 0.963; Aa: 0.024; aa: 0. c) AA: 0.668; Aa: 0.299; aa: 0. d) AA: 0.264; Aa: 0.345; aa: 0. e) AA: 0.25; Aa: 0.5; aa: 0. Question 17 Your answer is CORRECT. You measure allele frequencies at three loci that are all at equilibrium: f(A)=1, f(B)=0.5, f(C)=0. Which of the following fitness functions could result in these equilibrium frequencies? a) AA: 1, Aa: 0.8, aa: 0.5; BB: 0.5, Bb: 1, bb: 0.5, CC: 0.2, Cc: 1, cc: 1 b) AA: 0.8, Aa: 1, aa: 0.2; BB: 1, Bb: 0.5, bb: 0.5; CC: 0.5, Cc: 1, cc: 0. c) AA: 0.8, Aa: 0.4, aa: 1; BB: 1, Bb: 0.5, bb: 0.5; CC: 1, Cc: 0.5, cc: 0. d) AA: 1, Aa: 1, aa: 0.2; BB: 1, Bb: 0.5, bb: 0.8; CC: 1, Cc: 1, cc: 0.
e) It is impossible to distinguish between these fitness functions in regard to the expected equilibria. Question 18 Your answer is CORRECT. When researchers look at natural populations they almost always find a high level of genetic variation. All of the following processes can maintain genetic variation in population, EXCEPT: a) Heterozygote advantage b) Natural selection c) Homozygote advantage d) Variable environments e) Mutation-selection balance Question 19 NOT GRADED YET.
