KeenMT1S04

KeenMT1S04 - Na m e Last First Biological Sciences...

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Unformatted text preview: Na m e: Last First Biological Sciences lB—KEEN Spring Quarter 2004 Midterm #1. Please Read the Instructions First. Check your pages-~there are 12 pages in this exam. You are responsible for making sure that you have all the pages. This examination is worth 85 points. Bubble in the last 6 numbers of your ID # on the 6 lefthand columns of the box on your Scantron—~there will still be 3 blank columns on the right. Please bubble in Test Form A. Calculators cannot be used on the test. Multiple Choice Questions 1. Indicate your answers on the scantron sheet using a number 2 or a test scoring pencil. Press heavily, don’t stray out of the margins and completely erase any changed answers. 2. If you think that a multiple choice question is ambiguous or confusing, use the “explanation sheet” at the end of the examination to explain the problem. Put your name on this sheet-J tear them off to read them!! 3. There are 30 multiple choice questions worth 2 points each. Fill—in Questions 1. Use pen only (no grade corrections for pencil). 2. Write only one answer per question--you can elaborate on an answer, but you will not be given any credit if you write two different answers to the question. 3. Spelling rules: 1/2 credit for 2-3 letters wrong or transposed. No points will be given if the misspelling alters the meaning of the word. 2' 4. There are 3 fill-in questions worth 25 points in total. Page 9: Choose the one best answer: 1. For an AaBch individual, what fraction of the gametes will be ABC? a) 1/2 b) 1/3 c) 1/4 d) 1/6 e) 1/8 2. In a population of 2000 fruit flies, the wing shape gene has 2 alleles, W and w, each present at a frequency of 0.5. What should be the frequency of the Ww genotype under Hardy—Weinberg equilibrium .7 a) 0.10 b) 0.25 c) 0.50 d) 0.75 e) 1.00 3. Suppose you are sitting in a field on a summer evening and hear crickets chirping. Male crickets call to attract females. One set of sounds has a series of short chirps followed by a long pause. The other set of sounds has 3 long chirps and a short pause. Your field guide says that there are two closely related species of crickets present in the summer. From what you have heard, which of the following is likely? a) female crickets search for mates visually b) the two cricket species are mechanically isolated c) the two cricket species are temporally isolated d) female crickets identify males of their species by the call e) the two cricket species are spatially isolated 4. Still thinking about the crickets from Question #3, suppose female crickets occasionally select a male of the wrong species as a mate. Which of the following would still allow two distinct or "good" cricket species to persist? a) high survival and reproduction of hybrid offspring b) hybrid breakdown c) hybrid sterility d) b & c e) a, b & c ,2 5. The combination of a unique fur color pattern, odd vocalization, and the tendancy for crossed eyes, in Siamese cats makes a good example for: a) one gene affecting multiple phenotypic traits b) a polygenic trait c) the value of being heterozygous d) the dangers of mating with close relatives e) a wide norm of reaction 6. Si/Ilz's i’rionti’ri/cnsis and Autosyllis cndcnsis are the scientific names of two marine worms. i Into which group could we place these two taxa to indicate the closest level of relationship? a) species b) genus c) family d) order e) class 7. You are given a collection of beetle fossils from Mississippi. The fossils are 1 million years old. In a sample of 250 fossil beetles, the mean width of the beetle body is 7 mm, with a range from 3 to 10 mm. You measure 300 younger fossil beetles from the same site, finding a mean body width of 7 mm, with a range from 5 to 9 mm. What can you suggest about the beetle lineage? a) it has undergone directional selection b) selection has favored beetles with smaller carapaces c) the beetles exhibited positive assortative mating for size (1) the lineage has been divided into two species 0) it has been subject to stabilizing selection 8. After examining the beetle data from Question #7, which of the following is most likely to describe the genetic basis of body width? a) one gene with two alleles b) one gene with 3 or 4 alleles c) one pleiotropic gene d) several different genes that all contribute to body width e) a small genetic basis and a large environmental effect 9. You discover a unique caterpillar genotype where body color is determined by pigments in food. You clone the caterpillar and sell the clones as pets; if you feed them beets, they turn red, if you feed them mint leaves, they turn green, and a diet of carrots makes them orange. Your business does very well, but some caterpillars escape and live in gardens. Plants come in a lot of colors——what can we expect? a) natural selection will favor different c010red caterpillars in each habitat b) caterpillars that mate assortatively for color will have higher fitness c) caterpillar color will not respond to natural selection d) caterpillar color will be highly heritable e) all of the above will occur 2' 10. When there are 4 alleles for a gene, what is the maximum number of genotypes? a) 4 b) 6 c) 8 d) 10 e) 12 11. Imagine a genetic sequence that produces a particular protein. A mistake during chromosome duplication before meiosis alters the DNA resulting in a two—amino~ acid change in the protein. The DNA for the new protein ends up in a zygote. In comparison to the old protein, the new protein functions 20% less well at low temperatures, but 35% better at high temperatures. What has happened here? a) a new gene has been developed b) natural selection has taken place c) the gene has a new allele d) a polygenic trait now exists e) a polyploid organism has been formed 12. Following Question #11, the zygote with the new protein develops successfully into an earthworm. The worm experiences three months of warm temperatures, reaching sexual maturity 3 weeks earlier than 90% of the other worms. It mates, producing 5 young that survive to reproduce. The average worm pair produces two young that survive to reproduce. What can we predict if global warming continues? a) an increase in frequency of the new protein in future generations b) lower relative fitness for worms carrying the new protein c) genes for this protein will be Hardy—Weinberg equilibrium d) a new worm species will form e) a large increase in the mutation rate for this protein gene 13. You compare the number of alleles present in two populations of mallard ducks. The PGI gene has 5 different alleles in one population and only 2 alleles in the other. Both populations have 2000 birds now. What could have caused the difference in the two populations? a) founder effects b) natural selection c) a population bottleneck d) answers a and b e) answers a, b & c 14. Chicken feet contain a lot of connective tissue, so they can be boiled down to make a syrup that you think will protect soccer players from knee injuries. You plan to breed chickens for very large feet, make a lot of money, and retire at age 35. Your friend plots the average foot size in parental chicken pairs against the average foot size of their offspring. The slope of this plot is 0.25. Is your business likely to succeed? a) yes, this means that 75% of the variation is genetic and can be selected b) yes, 75% of chickens will have large feet c) no, only 25% of chickens will have large feet d) no, only 25% of the variation in foot size is genetically based e) no, only 25% of the chickens will survive to reproduce -4- USE THE ABOVE CLADOGRAM FOR QUESTIONS 15—18. X is the outgroup. 15. In the mouse clade, what is the most parsimonious position for the evolution of a curled tail held over the body? a) between P and O b) between Q and R C) between R and S d) between S and U e) between S and E 16. The pale body form with spots in animal A is most likely to be: a) derived b) ancestral c) areversal (1) very closely related to the outgroup color pattern e) correlated with small body size 17. Which of the groups below is paraphyletic? a) A + B b) C + D c) C + D + E d) A + B + C + D e) A + B + C + D + E 3‘ 18. Which trait appears to have evolved independently at least twice? a) a pale body with spots b) a pale body c) a long tail held over the body d) dark fur with spots e) very large body size 19. Suppose mouse species F and G, pictured on the previous page, live in rock crevices on mountain slopes. They shared a common ancestor 50,000 years ago, and measurements of fossil mice suggest that the ancestral population had a wide range of sizes. About 30,000 years ago, a population of moles moved into the habitat of the ancestral population, taking up all the average sized crevices. What sort of selection would this impose on mouse body size in the population? a) directional selection b) stabilizing selection c) divergent selection d) frequency—dependent selection e) sexual selection 20. What kind of mating would be favored in the mouse population after the mole invaded? a) positive assortative mating b) negative assortative mating c) random mating d) self-fertilization e) matings between close relatives 21. The ancestral mouse species lived across rocky hillsides. All hillsides contain a range of crevice sizes. If the number of rock crevices available to the ancestral mouse species was significantly reduced by the mole invasion, what might have occurred in the mouse population to produce the taxa we see now? a) allopatric speciation b) parapatric speciation c) sympatric speciation d) polyploidy e) hybridization between mice and moles 22. Suppose that safe hiding places in rock crevices are the major factor limiting mouse survival. Now suppose that moles become extinct in this location How would the loss of moles affect the relative fitness of hybrids between species F and G, if any hybrids formed? a) it would increase hybrid relative fitness 3 b) it would not change hybrid relative fitness c) it would decrease hybrid relative fitness d) it would drive hybrids extinct in a few generations e) it would make hybrids just as fit as offspring of pure type matings 23. Human populations often disperse for social or political reasons. The Old Order Amish left Germany about 300 years ago and dispersed to various parts of the world. The disperal groups were small, about 200 families each. W_hy might the frequency of a particular allele vary greatly among_the different dispersal groups, if the allele does mt confer an advantage, or cause any disadvantages, for those that possess it? a) natural selection favored it in some places b) positive assortative mating increased the frequency of this allele c) most of the dispersal groups went extinct d) founder effects are not predictable e) divergent selection occurs whenever organisms disperse 24. Picture a large population of frogs living in Green Pond. The frequency of allele Q in this population is 0.4. In two surrounding ponds, the frequency of the Q allele is 0.2 and 0.8. One spring, twice as many tadpoles as normal survive in Green Pond, and when the tadpoles develop into adult frogs, they leave Green Pond headed for the surrounding ponds. Next year, a geneticist notices that the frequency of the Q allele is rising in the first pond, and falling in the second pond. What could explain this? a) disruptive selection b) migration c) increased mutation rates (1) sexual selection e) frequency-dependent selection 25. Suppose the gene for flower color is on the same chromosome as the gene for leaf shape. The flowers come in blue or purple, and leaves are round or pointed. In the first generation, we see only two types of plants: those with purple flowers and pointed leaves and those with blue flowers and round leaves. In the second generation, one percent of offspring have purple flowers and round leaves. How do we explain this? a) independent assortment b) founder effects c) polyploidy d) crossing over e) mutation 26. If there is an error in meiosis, so that a gamete has more than the typical number of chromosomes, and this gamete fuses with another like it, the zygote would be: a) haploid b) diploid c) triploid d) polyploid e) multiploid 27. The earliest horses are known from fossils to be small dog-like animals that are placed in the genus Hyracotllcrium. Over evolutionary time, there has been a steady change in the way horses position the feet while running. The number of toes in contact with the ground has been reduced from 5 to 3 to 1. If we see this kind of change within a single lineage, we call it: a) stasis b) extinction c) anagenesis d) cladogenesis e) speciation 28. What is a sister taxon? a) the ancestor of two modern species b) the part of a lineage that did not go extinct c) when insects live on plants, each is the sister taxon of the other c1) one half of a lineage that has been split by cladogenesis e) the opposite half of a lineage to a brother taxon 29. You are studying leaf shape in a group of fossil plants. The ancestor has round leaves. At the first node, descendants have narrow leaves, but descendants of the second node have round leaves like the ancestor. How would you describe leaf shape? a) it is subject to reversals b) round leaves are derived c) round leaves are lost in descendants d) it is an excellent character for use in a phylogeny e) it shows unequal rates of evolution among branches of the tree 30. Several different plant lineages have descendants that live in the desert. These plants share certain features of the leaves and stems, but their flowers are quite different. What is/are the best explanation(s) for the shared leaf and stem morphology? a) homology b) independent evolution clue to common selective factors c) convergence '1“ d) answers a and c e) answers b and c FILL—IN QUESTIONS 3]. Most, but not all, elephants have tusks. Tusks are used in defense, but elephants can defend themselves in other ways. In most populations, tuskless animals are quite rare. However, tusks are highly prized by ivory collectors and poaching is a problem. Poachers kill elephants to harvest the tusks. In elephant populations where tusklessness was once rare and poachers have been present for several generations, the tuskless condition has become more frequent. Assuming natural selection is acting on these elephant populations, complete the problems below. a. (6 pts) Describe the 3 conditions necessary for natural selection, and explain how each condition would be met for the elephants. ii. iii. b. (1 pt) If poaching were the major factor affecting elephant survival, what would be the eventual outcome of natural selection? (1 pt) Suppose that government biologists managing the elephant population decide to protect the elephants by tranquilizing them and cutting off the tops of their tusks. Animals can survive this procedure. How will this change the outcome 30f natural selection that you predicted above? (1 pt) If the population is managed by biologists and females prefer to mate with tusked males, what would you predict as the outcome now? 32. Suppose you are hired by Insecticides—R-US to study cockroaches. The company has a good insecticide, but some cockroaches can consume it and still live. Animals that eat the insecticide and survive carry the T allele. You are hired to estimate allele frequencies for a population of cockroaches that have been exposed to the insecticide for a few generations. You estimate the frequencies of the 3 genotypes as: f(TT) : 0.05, f(Tt) : 0.50, and f(tt) : 0.45. Show your work for every question below. a. (2 pts) What is the frequency of the T allele in the population? b. (3 pts) What are the expected frequencies of the three genotypes under conditions for Hardy-Weinberg equilibrium? c. (2 pts) Compare the observed genotypic frequencies with those expected under Hardy-Weinberg equilbrium and note the differences. d. (1 pt) Is the population in Hardy-Weinberg equilibrium for this gene? e. (1 pt) You know that animals with the T allele can eat the pesticide and survive. How do the results of your comparison in part c fit with this knowledge? f. (1 pt) A survey of the scientific literature tells you that the T allele is typically present at less than 10% in natural roach populations. Homozygotes for the T allele need twice as many gut bacteria to digest their food properly. Given thisinformation, explain how you make more sense of your results from part c. g. (1 pt) Explain whether or not the T allele going to spread rapidly. -10- 33‘ (5 pts total) To discover the evolutionary rel antelope, you score 4 characters on each Species. Characters are shown below along with summ ationships among 3 species of The summary data for the 4 ary data for the outgroup. Outgroup : 0000 Antelope A = 1000 Antelope B = 1210 Antelope C = 1310 Fill in the distance matrix below. (6 spaces @ 1/2 point each). Outgroup A B C OutgrOup -- A -- B -- Sister taxa: I know this because: -11- Name Last First ID.# Explanation of thought processes Instructions: 1. Put your name at the top of the page. I tear the pages off to read them!!! 2. If you think that a question is ambiguous or confusing, indicate t} number, the answer you gave, 10 question and why you are concerned about thi. \ HI]S\VGI‘. Question # Answer you gave Problem with your choice -12- ...
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This note was uploaded on 05/26/2008 for the course BIS 1b taught by Professor Kimsey during the Spring '08 term at UC Davis.

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KeenMT1S04 - Na m e Last First Biological Sciences...

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