Name _____________________________________ PCB4674 Mid-term Exam 1. Feb. 6, 2012 KEY. Some full credit answers are shown. Work quickly. Put aside hard questions until you have answered the easy ones. Please write your name at the top of every page. Multiple choice questions. Circle the ONE best answer. (3 points each) . Correct answers in red. 1. An ancestral character state is A. A taxon thought to be close to the root of the tree you are studying. B. One that functions poorly. C. A species with lots of primitive characteristics. D. The state found in the outgroup to the taxon of interest. E. The state at the root of the Tree of Life. 2. Which of these is NOT a premise of natural selection? A. Variation among individuals B. Inherited variation C. Differences in survival and reproduction among individuals D. Variation causes differences in survival and reproduction E. Variation that benefits the species 3. What evidence do scientists use to judge how old the earth is? A. Radiometric dating of meteorites B. Carbon 14 dating C. The temperature of the earth’s core D. The molecular clock E. Relative dating 4. What is the best summary of the relevance of the Tree of Life for evolution? A. Character states are found randomly in the Tree, suggesting that natural selection readily adapts organisms to their environment. B. The Tree of Life suggests that the traditional Linnaean classification is always consistent with evolutionary history. C. The similarity of groupings arrived at using different types of characters suggests that the Tree is consistent with inheritance of character states from common ancestors. D. The Tree found using molecular characters is very different from the Tree based on phenotypic characters, suggesting that DNA and traits evolve according to different rules. E. The Tree tends to group together organisms that live in very different parts of the earth, suggesting that long-range dispersal is a very frequent occurrence. 5. What distinguishes maximum likelihood analysis from other methods of determining a phylogeny? A. The use of a model of evolution. B. The assumption of independence. C. The assumption of non-random mating. D. The use of fossil dates. E. It gives trees that are more likely to be true.Name _____________________________________ Gorilla Orang. Human Chimp A. Gorilla Orang. Human Chimp B. Gorilla Orang. Human Chimp C. Gorilla Orang. Human Chimp D. Gorilla Orang. Human Chimp E. 6. A synapomorphy is A. A novel element in the nervous system. B. A behavior that is not explicable using evolutionary reasoning. C. A beehive that has a football shape. D. A shared derived character state. E. A shared ancestral character state. 7. Which of the following best represents the current consensus phylogeny of the great apes? Orang. is the orangutan, and chimp represents the two species of chimpanzee.Name _____________________________________ 8. In the tree above, which of the following pairs of taxa are sisters? A. Armored dinos and duckbills B. Prosauropods and theropods C. Saurischians and ornithischians. D. Crocs and pterosaurs E. Archosaurs and dinosaurs 9. What specific event happens at each of the dots? A. Evolution B. Speciation C. Fossilization D. Anagenesis E. Mutation www.science20.comName _____________________________________ True-False (Multiple multiple choice) questions. Circle ALL the answers that are True for each question. (5 points each). Correct answers in red. 10. Which of the following are assumptions of a parsimony approach to phylogeny? A. Change occurs at the same rate throughout the phylogeny. B. Each character has an independent evolutionary history. C. The rate of evolution is dictated by a combination of mutation rate and population size. D. The rate of evolution is low. E. Taxa are sampled randomly. 11. Which of the following are causes of homoplasy? A. Parallelism B. Orthology C. Complexity D. Reversals E. convergent evolution 12. Which of the following could help to explain why untreated HIV infections are fatal to human hosts? A. Natural selection on HIV to get to new hosts. B. Repeated transmission of HIV from apes to humans. C. Natural selection on HIV to reproduce within the human host. D. The fact that HIV has jumped to humans from chimpanzees. E. The fact that HIV has been in humans for thousands of years. 13. Which of the following biogeographic facts provide good evidence for evolution? A. Fossil taxa in the same area as their living relatives. B. Adaptive radiation C. Good fit of organisms to their environment D. Stasis E. Convergent evolution on different continentsName _____________________________________ 14. Draw lines to match the event or fossil in column A with the approximate date in column B and the geological period in column C. There is a good match for each one. As an example, I have drawn the lines connecting modern human fossils to the corresponding date and period. A: Event B: Million years ago C: Period First fossil Homo sapiens 5.4 Tertiary First fossil insect 0.1 Jurassic First fossil mammal 408 Cambrian Last chimp-human common ancestor 400 Quaternary First fossil vascular plant 206 Devonian First fossil insect 400 mya Devonian First fossil mammal 206 mya Jurrasic Last chimp-human common ancestor 5.4 mya Tertiary First fossil vascular plant 408 mya DevonianName _____________________________________ 15. (8) Give a specific example of a character state in a fossil taxon that is intermediate between those of living relatives. Be specific about the character, the character state, how it differs from living relatives and which living relatives. Tiffany Campbell: The fossils of other hominids show an intermediate character for the shape and size of the jaw. In apes the jaw is large and formed with a U with straight edges. In intermediate forms the jaw is slightly reduced and forms a smoother curve. In modern humans the jaw is much reduced and is shaped in a smooth U. Michelle Kortyna: The legs of Tiktaalik are intermediate between the fins of lobe-finned fish and the legs of a modern reptile. The lobe-finned fish has a distinct fin shaped appendage which is used for swimming. Tiktaalik’s forelimbs had bone structures very similar to modern reptiles but in a more condensed, less defined form. Tiktaalik’s forelimbs ended with primitive digits. Modern reptiles