Name (2 points if printed in pencil)______Biology 425 Exam 1A
Please answer the following multiple choice questions (2 pts each). Note: there are numerous extra points built into this exam, so you can miss quite a few questions and still score 100% (in other words, you probably will end up doing better than you think you are doing!).
1. From a population standpoint, what are distinctions between the AIDS pandemic in Africa and the rest of the world? a) the incidence of AIDS in Africa is higher b) more men than women are afflicted in Africa c) a+b d) neither a nor b
2. Which cells in the human immune system have the shortest lifespan?
a) naïve T cells b) memory T cells c) effector cells
3. Do individuals evolve? a) yes b) no
4. For the Eda rescue experiment that created transgenic sticklebacks, what was the phenotype of the parents? a) both complete b) both low c) one complete, one low
5. Bell’s experiments on sticklebacks in Loberg Lake showed
a) a rapid increase in the frequency of the complete-plated morph b) evidence for a two-year lifecycle c) a+b d) neither a nor b
6. Circle the graph that best shows the molecular clock assumption?
Number of
Base pair
substitutions
(Y axis for
all four graphs)
Amount of time elapsed since genetic divergence
7. According to Gould, what do orchids have in common with the Panda’s thumb?
a) adaptation usual leads to perfect solutions to problems b) natural selection operates on existing variation c) natural selection can operate on structures that originally served very different functions d) a+b e) a+c f) b+c g) all are true
8. Which of the following is true about bootstrapping a sequence of DNA that is 500 bases long?
a) Each position (or site) is randomly chosen for each data set b) it is unlikely that the actual DNA sequence will be one of the data sets used in the bootstrap analysis
c) bootstrapping is used to determine which tree is most parsimonious
d) a+b e) a+c f) b+c g) all are true
9. A purine replaces a pyrimidine in a a) deletion b) indel c) transition d) transversion e) duplication
10. What did Ellegren’s analysis of microsatellite mutations show?
a) dinucleotide repeats tended to get longer, while tetranecleotide repeats tended to get shorter
b) dinucleotide repeats tended to get longer, while tetranecleotide repeats had no trend
c) dinucleotide repeats and tetranecleotide repeats tended to get longer
d) dinucleotide repeats tended to get shorter, while tetranecleotide repeats tended to get longer
e) dinucleotide repeats tended to get shorter, while tetranecleotide repeats had no trend
f) dinucleotide repeats and tetranecleotide repeats tended to get shorter
11. Humans have a DNA sequence that looks like the chimp gene for the CMAH enzyme, except that humans have a 92 base pair deletion that makess it nonfunctional. This is an example of a
a) homoplasy b) vestigial trait c) reversal d) none of these
12. In the greenish warbler ring series a) the northwestern and northeastern forms will readily mate in their contact zone b) the southwestern and southeastern forms will readily mate in their contact zones c) a+b d) neither a nor b
13. The principle that geological processes taking place now operated similarly in the past is
a) ontological naturalism b) homology c) homplasy d) catastrophism
e) uniformitarianism
14. Large fruit in domestic tomatoes is due to a) high expression of a repressor protein
b) low expression of a repressor protein c) high expression of auxins
d) low expression of auxins
15. Research by Jones and Reithel on snapdragons showed that a) yellow flowers had more visits by bees b) yellow flowers had higher seed set c) a+b d) neither a nor b
16. The droughts of 1977 and 2003 affected medium ground finches by selecting for
a) increased beak depth in both cases b) decreased beak depth in both cases
c) increased beak depth in 1977, but decreased in 2003 d) decreased beak depth in 1977, but increased in 2003
17. How does the eel sperm flagellum differ from the more typical eukaryotic flagellum?
a) it lacks the central pair complex b) it lacks the A tubule c) it lacks the B tubule
18. Why are short and long interspersed elements so useful in reconstructing phylogeny?
a) because homoplasy is very common b) because their loss is associated with loss of a part of the host genome c) a+b d) neither a nor b
19. How did Chameleons get from Africa to India a) they didn’t
b) they floated on rafts c) they road chunks of Gondwana as it broke up
20. Most of the mutations isolated by Denver and colleagues from C. elegans nuclear DNA were
a) transitions b) transversions c) indels
21. Which is the more common cause of gene duplication?
a) retrotransposition b) unequal cross-over
22. Est inversions in Drosophila are a) more common in higher latitudes in North America
b) more common in higher latitudes in south America c) a+b d) neither a nor b
23. Individuals of genotype CCR5-∆32/ CCR5-∆32 are a) more susceptible to HIV infection
b) more common in northern Europe c) a+b d) neither a nor b
Short answers
1. (4 pts) At time 0, patients were switched from AZT to another anti-HIV treatment (DDI). Draw the curves representing the sensitivity of the HIV virus to each of the two drugs after the switch.
sensitivity
0 2 4 6 8
time (months)
2. (3 pts) After 8 years of chronic HIV infection, the HIV RNA stops diverging (as measured in genetic distance) from the initial RNA of the infecting HIV. Why?
3. (3 pts) If you find a stickleback fish with four dermal plates, what is most likely its genetic constitution (hint: remember to consider all of the genes influencing the phenotype)?
4. (4 pts) Research on the beak of the finch yielded the following graph. Give two plausible interpretations of why this relationship could exist in finches.
Offspring
Beak
depth
parent beak depth
5. (6 pts) Please answer the questions based on the tree below.
A B C D E F G
a) Which species (may be more than one) is/are most closely related to E.
b) Which species (may be more than one) is/are most closely related to A
c) The area surrounded by the circle forms a ______group.
6. (6 pts) When MutS+/MutS+ E. coli were competed against MutS-/MutS- E.coli in a novel environment (with equal initial population size) there were some interesting dynamics.
a) Draw a graph that shows the results of this experiment
b) provide an explanation for this result.
7. (3 pts) Please explain why the bones in the forelimb bones in bats and birds are homologous, but the use of forelimbs for powered flight is homoplastic in these two groups.
8. (3 pts) Give a plausible explanation for why humans, chimps and orangatans share the 16 MYA processed pseudogene (ASY7), while it is missing in gorillas.
9. (6 pts) a) Build a tree using the following DNA base sequence information
Species A ATTGCAGCA
Species B CTTGTAGGC
Species C CATGTAGGC
Species D ATTGCAGCC
Species E CGAGTATTA
b) Identify one location on your tree where a reversal occurred (and what was that reversal)?
Name ______(10 pts) There is lots of extra credit embedded in this exam. Ace it!
(2 pts) The following statements pertain to questions 1-9. Fill in the letter that describes the process that best explains each statement.
A) frequency dependent selection B) directional selection
C) underdominance D) heterozygote superiority (heterosis)
E) not an evolutionary process
_____1. explains the world-wide distribution of sickle-cell anemia
_____2. Explains fruit set in two color morphs of elderflower orchids
_____3. the very flat insect on a branch probably resulted from this type of selection
_____4. Susceptibility to kuru
_____5. Fitness of individuals with a trait is variable
_____6. Mosquitoes evolve resistance to DDT
_____7. Foster’s research on selection on Drosophila with compound chromosomes
_____8. Decrease in lactose intolerance in Euro/American humans
_____9. Change in human cranial shape from American Colonial period to present
Multiple choice (2 pts each)
10. Genetic drift leads to evolutionary change more rapidly in which size populations?
a) small b) medium c) large d) infinite
11. Genetic drift is more likely to lead to fixation of an allele more rapidly in which size population?
a) small b) medium c) large d) infinite
12. Collared lizards in the Ozark Mountains have a) a high degree of heterozygosity
b) fixation of different alleles in different small populations c) a+b d) neither a nor b
13. Referring to question 12, what is an expected result of controlled burns conducted by the Missouri Department of Conservation? a) more gene flow b) more genetic drift c) larger populations
d) a+b e) a+c f) b+c g) all of the above
14. Why does Kimura argue that natural selection’s effect on allele frequencies is relatively small?
a) beneficial mutations are rare b) deleterious mutations are selected out of the population before they get established c) a+b d) neither a nor b
15. Gojobori’s study of the RNA sequence in influenza showed a) support for the neutral theory
b) a much higher rate of replacement mutations than synonymous mutations c) a+b d) neither a nor b
16. Andrew Young’s study of population size, allele richness and polymorphism showed a) a higher allele richness in Eucalyptus than the other species b) polymorphism increased with population size, but allele richness did not c) good evidence for genetic drift being a more potent force in large populations d) a+b e) a+c f) b+c g) all of the above
17. What is the inbreeding depression if the fitness of a selfed plant is 75% that of the fitness of an outbred plant a) .25 b) .5 c) .75 d) none of these
18. What type of mating system do prairie chicens have a) monogamy b) polyandry c) lek polygyny
d) none of these
19. Which is true of the prairie chicken population in Illinois? a) hatching success has increased since 1990 b) individuals were imported from other states to increase gene flow c) a+b
d) neither a nor b
20. Experiments by Paul Weeks provide evidence that the interaction between oxpeckers and cows is best described as a) mutualism b) competition c) parasitism d) none of these
21. Which of the following treatments did Erick Greene use for his exeriments on spider mimicry by tephritid fllies a) Zonosemata with own wings cut and reglued b) Zonosemata with housefly wings
c) Housefly with Zonosemata wings d) a+b e) a+c f) b+c g) all of the above
22. Which groups show large testes in species with low levels of sperm competition? a) primates
b) bats c) a+b d) neither a nor b
23. Which is not part of Felsenstein’s comparative method for evaluating phylogenetically independent contrasts? a) figure out the phylogeny of the species b) plot all sister species on a scatterplot
c) move the lines connecting the contrasts, so that the species with the lower x-value is at the origin
d) erase the point at the origin e) convert all continuous variables to nominal variables
24. Bat species with high relative testes size will usually have a) high relative brain size
b) moderate relative brain size d) low relative brain size
25. According to research by Schenske and Agren, female flower size in Begonia involuctra has been determined by a) directional selection for smaller female flowers b) tradeoff between flower color and floral retention c) a+b d) neither a nor b
26.Which of the following is an assumption of the Hardy-Weinberg equilibrium?
a) no natural selection b) no gene flow c) no random mating d) no genetic drift
e) all are assumptions of the Hardy-Weinberg equilibrium
27. Why have body feather lice switched hosts less frequently than wing feather lice?
a) because they are more firmly attached to the body feathers than the wing feather lice are to the wing feathers b) they don’t hitchhike very often on parasitic flies c) a+b d) neither a nor b
28. According to Gould and Lewontin, arguing that the spandrels of San Marcos were built as spaces to house mosaics is analogous to a) arguing that noses are adaptations for supporting eyeglasses
b) arguing that all adaptations evolved to serve their current function c) a+b d) neither a nor b
29. (3 pts). DD and Dd individuals have 25% survival rates and dd individuals have a 20% survival rate. They all produce the same number offspring on average. Calculate the fitnesses and selections coefficients.
30. (9 pts) a). In a population of elk 10 males with the largest antlers fathered 200 fawns while the 100 smaller antlered males fathered 220 fawns. What are the reproductive fitnesses and selection coefficients of the 2 types of males?
b) Of the 10 large antlered elk that mated in the spring, five survived through the following winter to mate again. Of the 100 smaller antlered males, 70 were still alive the following spring. What are the survival fitnesses and selection coefficients of the 2 types of males?
c) What are the overall fitnesses of the large and small antlered males in question 30 if you consider their abilities to survive and reproduce?
31. (4 pts) A population of reindeer is in Hardy-Weinberg equilibrium for a gene for nose color, in which having a red nose is determined by a recessive allele. A population geneticist named Sandy Claws finds 64 red-nosed reindeer in his flock of 100. What is the frequency of the recessive allele.