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Course Number: BIO 200, Fall 2009

College/University: SUNY Buffalo

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This exam in worth 100 points in the whole course. Evolutionary Biology Exam II, Fall 2008 Part I You may take this part of the exam with you. D A. Multiple Choice Questions. Choose the best possible answer. Use the bubble sheet. (1 pt. each) 1. When selection acts to eliminate one extreme from an array of phenotypes it is called (A) natural selection (B) stabilizing selection (C) disruptive selection (D)...

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exam This in worth 100 points in the whole course. Evolutionary Biology Exam II, Fall 2008 Part I You may take this part of the exam with you. D A. Multiple Choice Questions. Choose the best possible answer. Use the bubble sheet. (1 pt. each) 1. When selection acts to eliminate one extreme from an array of phenotypes it is called (A) natural selection (B) stabilizing selection (C) disruptive selection (D) directional selection (E) artificial selection. 2. Which one of the following is not an example of a reproductive isolating mechanism? (A) sympatric isolation (B) behavioral isolation (C) ecological isolation (D) mechanical isolation (E) temporal isolation. 3. A behavior that has evolved to aid relatives, although at personal risk, and thus increases the chance of your genes being passed on to the next generation is known as (A) altricial behavior (B) instinctive behavior (C) kin selection (D) operant conditioning (E) adaptive behavior. 4. Which plants are characterized by a conducting system, the possession of cuticles, specialized stems, and roots, stomata, and, in many species, seeds? (A) liverworts (B) mosses (C) tracheophyta (D) horsetails (E) club mosses. 5. The infection cycle of HIV includes all of the following steps except (A) attachment (B) entry (C) replication (D) immediately killing the host cell (E) viral DNA integrates into the host chromosome. 6. The gametophyte is green and nutritionally independent in (A) mosses, liverworts, and ferns (B) angiosperms (C) gymnosperms (D) conifers (E) cycads. 7. A microbiologist is conducting a research project on chemoautotrophs. This means that the investigator is examining certain aspects of a bacterium that (A) can oxidize sulfur (B) is a purple non-sulfur bacteria which depends on light (C) obtains carbon from organic molecules (D) can use the energy from sunlight to build organic molecules from carbon dioxide (E) uses light as its energy source and carbon for organic compounds. 8. The biological species concept of Ernst Mayr can be applied to all of the following except (A) sympatric organisms (B) allopatric organisms (C) eukaryotic organisms (D) prokaryotic organisms (E) asexually-reproducing organisms. 9. Plants lacking well-developed conducting systems such as mosses, liverworts, and hornworts have been called (A) gametophytes (B) sporophytes (C) angiosperms (D) gymnosperms (E) bryophytes. A C C D A A E E C 1 10. The type of speciation that geographically isolates populations and results in the divergence of distinct species is called ____________ speciation. (A) gradual (B) sympatric (C) allopatric (D) sexual (E) adaptive. 2 11. The genetic alteration of a cell's genome by the introduction of foreign DNA is called (A) transfection (B) transformation (C) transcription (D) translation (E) transduction. 12. The recessive phenotype of a trait occurs in 25% of a population. There are no selection pressures affecting this trait. What would be the expected frequency of the dominant allele after six generations of continued non-selection? (A) 0.25 (B) 0.306 (C) 0.50 (D) 0.494 (E) 0.75 13. If populations within a common area split into species, the process is known as (A) sympatric speciation (B) allopatric speciation (C) racial speciation (D) ecotypical speciation (E) reproductive speciation. 14. The California populations of the Northern elephant seal are descendants from a very small population of seals that was over-hunted in the 1890s. Heterozygosity in this population would be expected to be ________ due to ________________. (A) slight; a bottleneck effect (B) slight; the founder effect (C) great; disruptive selection (D) great; a bottleneck effect (E) great; assortive mating. 15. In the southeastern U.S., two species of wild lettuce (Lactuca) do not usually form hybrids, because they bloom at different seasons. The means of isolation appears to be (A) behavioral (B) temporal (C) geographical (D) mechanical (E) ecological. 16. A process unique to angiosperms is (A) single fertilization (B) double fertilization (C) syngamy (D) alternation of generation (E) seed production. B 17. You are studying a population of geese in which there are two color phases, brown and gray. Color in this species is controlled by a single gene, with brown dominant to gray. A random sample of 250 geese shows that 210 are brown. What percentage of the brown geese are heterozygous? (Assume that the population is in Hardy-Weinberg equilibrium.) (A) 36% (B) 43% (C) 48% (D) 57% (E) 84%. 18. In disruptive selection, over time (A) a population goes extinct (B) the most extreme outliers of a population are eliminated (e.g., the largest beaks and smallest beaks are eliminated) (C) the population is strongly selected for in one direction (e.g., larger beak size) (D) the population is strongly selected for in two directions (e.g., larger beak size and smaller beak size) (E) a population increases its variation (e.g., a wide selection of all beak sizes). 19. A layer of lipoprotein and glycoprotein that covers the outer surface of some viruses is the (A) capsid (B) casing (C) envelope (D) membrane (E) viroid. 20. Which radioactive dating method would you use to date the age of an artifact from the pyramids of Egypt? (A) Uranium-Lead (B) Potassium-Argon (C) Rubidium-Strontium (D) Carbon-Nitrogen (E) Hydrogen-Helium B C A A B D D C D 3 D 21. In which of the following characteristics, prokaryotes and eukaryotes are similar? (A) cell division (B) internal compartmentalization (C) flagella (D) contain ribosomes (E) enzymes localized in the plasma membrane. 22. Which of the following is not true about prokaryotes? (A) They are the oldest organisms on Earth (B) They are the structurally simplest organisms (C) They are the most abundant cellular life forms on Earth (D) They contain organelles (E) They are found in fossils 3.5 billion years old. 23. The gene pool includes (A) all of the fitness within a population (B) all of the individuals within a population (C) all of the mutations within a population (D) all of the adaptations within a population (E) all of the alleles of genes within a population. 24. Pea fowl (peacocks and peahens) show sexual dimorphism. Which statement best describes the graphed data? D E D (A) There are no peacocks with less than 140 eyespots (B) The fewer eyespots that a peacock has in his tail, the more mates he attracts (C) Actually eyespots have very little to do with mate-attracting activities (D) The more eyespots that a peacock has in his tail, the more mates he attracts (E) There are no peacocks with more than 165 eyespots. 4 D C 25. Sickle-cell anemia is a classic example of (A) founder effect (B) genetic bottleneck (C) point mutation (D) heterozygote advantage (E) heterozygosity. 26. A type of isolating mechanism that leads to reproductive isolation by preventing the formation of hybrid zygotes is called _____________ isolating mechanism. (A) hybridization (B) postzygotic (C) prezygotic (D) adaptive (E) differential. 27 Prokaryotes undergo a process that produces cells that are identical. This process is called (A) mitosis (B) meiosis (C) conjugation (D) binary fission (E) syngamy. 28 Where would you expect to find the enzymes for the Krebs cycle? (A) nucleus (B) Golgi body (C) chloroplast (D) mitochondria (E) cytoplasm. 29. If the frequency of an autosomal recessive trait in humans is 490 out of 1000 births, what would be the expected frequency of homozygous dominants for the trait if we assume that the gene is in Hardy-Weinberg equilibrium? (A) 0.09 (B) 0.18 (C) 0.42 (D) 0.49 (E) None of the above. 30. A keystone species is (A) the largest animal in a habitat (B) the species that lives the longest (C) the species with the largest number of individuals (D) the species that occupies the largest home range (E) the species whose presence or absence has the greatest impact on the ecosystem. 31. The direction of genetic information transfer in a retrovirus (such as the HIV) is (A) DNA to mRNA to protein (B) RNA to DNA to mRNA to protein (C) DNA to protein (D) RNA to mRNA to protein (E) RNA to protein. 32. Angiosperms are primarily characterized by all of the following except (A) ovules are enclosed within other tissues at the time of pollination (B) a seed develops within a carpel (C) the ovary matures into the fruit (D) free water is required for pollination (E) they bear flowers which are modified stems bearing modified leaves. 33. Adaptive radiation is best described as the (A) existence of groups of closely related species recently evolved from a common ancestor (B) existence of groups of distantly related species recently evolved from a common ancestor (C) existence of groups of closely related species recently evolved from different ancestors through hybridization (D) existence of individuals of closely related species that originated in different areas within diverse habitats, but that have rejoined as a single species. 34. Plasmids are distinguished from bacterial chromosomes in that (A) plasmids are circular, bacterial chromosomes are linear (B) plasmids occur in the cytoplasm, bacterial chromosomes occur in the nucleus (C) plasmids are composed of RNA, bacterial chromosomes are composed of DNA (D) plasmids have few genes, bacterial chromosomes have many genes (E) plasmids consist of single-stranded nucleic acids, bacterial chromosomes consist of double-stranded nucleic acids. D D A E B D A D 5 B 35. Two groups of organisms that differ from one another in one or more characteristics and do not hybridize extensively if they occur together in nature are considered to be different (A) races (B) species (C) kingdoms (D) hybrids (E). cohabitants. 36. Virulent viruses multiply within infected cells and eventually (A) cause an alternation of generations in the host cell, releasing new viruses (B) cause the transformation of the host cell, releasing new viruses (C) cause lysis of the host cell, releasing new viruses (D) cause the transduction of the host cell, releasing new viruses (E) cause a transfer of material from the host cell, releasing new viruses. 37. The production of new species through hybridization is sometimes made easier in plants by (A) adaptation (B) meiosis (C) parthenogenesis (D) hybrid sterility (E) polyploidy. 38. Phages are viruses that can infect (A) humans (B) plants (C) insects (D) farm animals (E) bacteria. 39. In small populations, frequencies of certain alleles may change by chance alone. Such random change in the frequency of alleles is called (A) mutation (B) migration (C) genetic drift (D) nonrandom mating (E) selection. 40. Insect workers propagate more of their own alleles by helping their mother reproduce rather than by reproducing themselves; thus, they share a larger fraction of their ___________ with the next generation. (A) food resources (B) time (C) genome (D) ability to defend their nest (E) home. 41. Certain small towns in the western United States have remained isolated and inbred since their settlement many years ago. Some alleles are more common in these communities as compared to the rest of the population. This effect is known as (A) artificial selection (B) directional selection (C) disrupting selection (D) Hardy-Weinberg principle (E) founder principle. 42. A gene is represented in the gene pool of a population of 10,000 individuals by a dominant (W) and recessive allele (w). If the initial frequency of W in the pool is 0.7, how many generations of complete selection against it would be required to eliminate all alleles W from the population? Assume that there is no mutation and the population meets all other HardyWeinberg conditions. (A) 1 (B) 2 (C) 5 (D) 20 (E) can never be eliminated. 43. The genotype frequencies in a population with no evolution occurring are AA = 0.25, Aa = 0.5, aa = 0.25. By removing all AA individuals before they reproduce and assuming the population will remain under Hardy-Weinberg conditions, what will be the frequency of aa individuals in the next generation? (A) 0.25 (B) 0.33 (C) 0.5 (D) 0.67 (E) 0.75. C E E C C E A D 6 E 44. A virgin pine forest covers a valley, and one of the inhabitants is a red squirrel species. A large volcanic eruption occurs and separates the valley with a huge lava flow that the squirrels cannot cross, thus producing two isolated populations of squirrels. What change needs to occur for the two populations of squirrels to become separate species? (A) The two squirrel populations must eat distinct species of plants (B) The area that the squirrel populations occupy changes so that the squirrel populations exist in distinct habitats (C) The fur color of the two squirrel populations must become distinct (D) The two squirrel populations select mates using the same sexual behavior (E) The two squirrel populations become reproductively isolated. 45. Most adult tracheophyte plants represent the (A) epiphyte generation (B) sporophyte generation (C) spore generation (D) gametophyte generation (E) angiosperm generation. 46. The genetic contribution of an individual to succeeding generations, compared with that of other individuals in the population, is known as (A) variation (B) microevolution (C) macroevolution (D) fitness (E) adaptive makeup. 47. Darwin proposed that natural selection occurs in an environment by (A) favoring heritable features that make the organism better suited to survive and reproduce (B) producing a constant number of offspring while in that environment (C) surviving for a fixed amount of time (D) resisting the environment and keeping the environment from changing (E) favoring those individuals with the most favorable acquired characteristics. 48. Which one of the following choices states a major difference between the life cycle of an angiosperm and a gymnosperm such as pine? (A) Angiosperms are dioecious; pines are not. (B) Angiosperms use a pollen tube to deliver sperm to the egg; pines do not (C) The tissue surrounding the embryo is triploid in angiosperms; it is diploid in pines (D) The megaspore mother cell is diploid in angiosperms; it is haploid in pines (E) Microspores are produced by meiosis in angiosperms; they are produced by mitosis in pines. 49. All viruses are constructed of (A) DNA with a protein wrapping, called a capsid (B) RNA with a protein wrapping, called a capsid (C) either DNA or RNA with a protein wrapping, called a capsid (D) either DNA or RNA, however many do not have the capsid. 50. The production of new species through hybridization is especially important in (A) finches (B) fruit flies (C) humans (D) plants (E) mules. B D A C C D BIO 200A EVOLUTIONARY BIOLOGY Exam II Part II Fall 2008 KEY _________________________ 7 Name ________________________________ TA Name ________________________________ Lab Day & Time B. Fill in the blank with the best answer. Be as specific as possible. (1 pt each) Hox genes ________ 1. What do we call genes that control a cluster of other genes during Homeotic genes__ embryological development? hyphae __________ (mycellium) co-evolution_ _______ conjugation_ __________ __O2_____ 2. What are thread-like cellular structures that make up the body of a fungus called? 3. What do we call the relationship when two species interact, each one modifying the evolution of the other? E.g. myxoma virus and rabbits in Australia. 4. What is the process called when a plastid is passed from one bacterium to another? 5. What is the byproduct of photosynthesis in blue green bacteria? _fungi_____ 6. Lichens are the mutualistic relationship of algae and __________. ____5_____ 7. If a skin cell of an animal usually has 10 chromosomes, how many chromosomes would its sperm cell have? mitochondria 8. Where is O2 used in the eukaryotic cell? addition or subtraction __________ (deletion) 9. What kind of point mutation could lead to a frame-shift? _Mendel___ 10. Who was responsible for demonstrating that the blending hypothesis of heredity was wrong? C. Define these terms, give an example, and answer the follow-up question. (4 pts. each) 1. Vestigial structures: Structures with no apparent function Example: appendix, muscles to move the ears, coccyx, goose bumps, eyes of blind fish How does their existence provide strong evidence for evolution? 8 The creationist or intelligent design hypothesis does not provide any explanation for the presence of vestigial structures but the evolution theory does; i.e. vestigial structures once had a function in the ancestors of these organisms. 2. Sexual selection: Differential reproduction by individuals in a species that occurs because individuals have different success in obtaining mates. There are two types: male fighting and female choice. Example: An e.g. of males fighting for breeding rights would be two male deer battling over the rights to breed with a female. An e.g. of female choice would be a female pea hen choosing the most beautiful peacock for breeding. Explain how this could generate an apparently "run-away" process. What is to stop this from happening? In a female choice situation where the female of a species has a built in bias favoring certain male traits, there will be a strong selection pressure favoring males with the trait. So her male offspring will have the trait and her daughters will favor the trait in their male choice. Each generation this trait will become more and more exaggerated until there are counteracting natural selection forces that come into play, i.e. the trait starts to become a liability e.g. when the peacock tail is so large that the male can't escape predators. 3. Allopatric species formation: Occurs when two populations of a species become separated by a natural barrier and over time they become so different that they can no longer interbreed (reproductively isolated). Example: Two populations of squirrels became separated by the Colorado River in the Grand Canyon about a million years ago and now they are distinct species on the north and south rim of the canyon. How could this process be disrupted? The process of speciation can be stopped or reversed if the physical barrier disappears at any time before the two populations have become reproductively isolated. If this occurs, then the two populations will interbreed and the speciation process will stop. D. Explain these ideas. Do not be superficial in your answers. (4 pts each) 1. How can we explain the altruistic behavior of some animals since it apparently runs counter to an individual's genetic self interest? We can explain it easily if the altruistic act occurs between closely related individuals. This is kin selection. i.e. Relatives share the same genes, so that if the altruistic act helps your relative survive and reproduce, you are enhancing the success of your own genes. Thus, the way to evaluate fitness is not simply to think of individual fitness but inclusive fitness which considers all of the genes shared by a group of organisms. 2. How can we explain the fact that two species of birds look rather similar when they live in different areas, but they look quite different when they live together? 9 This is an example of resource partitioning. When the two species are apart they can look similar, eat similar foods and have similar behaviors and survive quite well. But when they both are together, there will be a strong selective pressure on them to specialize, eating different foods, etc. If this doesn't happen then one species will probably out compete the other and cause it to become extinct. (competitive exclusion principle). 3. How can pleiotropy maintain an unfit trait in a population? Pleiotropy is the situation when a gene controls several traits (e.g. Marfan's syndrome). So if one of these traits is "bad" but one of the others is "good," then this gene can be maintained in a population rather than be eliminated by natural selection. e.g. cystic fibrosis continues to exist in the human population is spite of the fact it is a terrible disabling condition. Yet the gene responsible for this appears to also be advantageous in preventing severe diarrhea, a condition that kills large numbers of people worldwide. 4. Birds need large complex feathers to fly. Small feathers can't do the job. How can we explain the gradual evolution of feathers if there is no selective advantage for feathers until they are large? Since all the steps in evolution must have a selective advantage over previous steps, small feathers must have had a selective advantage that did not involve flight. i.e. Feathers must have been used for other functions before they were used to fly. e.g. Perhaps they were important in temperature regulation (insulation) or in behavioral displays or ...? It is only when they got large enough, then they also could be used in flight. E. Compare and contrast the following terms. (6 pts. each) 1. The infolding and endosymbiotic hypotheses for the origin of the eukaryotic cell. Be sure to give our current understanding on the subject. The infolding hypothesis argues that over time a prokaryotic cell's membrane invaginated more and more extensively forming the membrameous organelles e.g. nuclear membrane, er, Golgi, vesicles, vacuoles, mitochondria and chloroplast. The endosymbiotic hypothesis argues that we can explain where the mitochondria and chloroplasts (and perhaps the flagella and cilia) came from by claiming they are the result of symbiosis between bacterial cells. Thus, an archea bacterial host cell engulfed an aerobic bacterium and this became our modern day mitochondria. In a later symbiotic event, the archaeobacteria with mitochondria engulfed a blue green alga and this became our modern day chloroplasts. (In a more disputed scenario, some scientists claim that flagella and cilia are symbiotic spirilla bacteria.) Today we believe that the infolding hypothesis adequately explains most membrameous organelles but that the origin of the chloroplast and mitochondria are best explained by the endosymbiotic hypothesis. 10 2. The evolutionary explanation vs. the Intelligent Design explanation of adaptation. Be sure to give our current scientific understanding of topic. The evolutionist's explanation of adaptation is that natural selection operating on the variations that are present in a population progressively brings about modifications in the anatomy, physiology, biochemistry and behavior of an organism. Thus, organisms evolve better and better characteristics that make them more fit than previous generations. e.g. The beak of the Galapagos finches are better designed to open seeds than they were previously. The Intelligent Design explanation suggests that an intelligent designer (God?) designed organisms the way they are to fit their environmental needs. There is no mechanism that is proposed for this process. Because of this lack and the fact that the Designer is not identified but presumed to have supernatural powers, investigation of this hypothesis lies outside of the realm of science. The evolutionary explanation is the accepted one currently. 11

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