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Unformatted text preview: Compiled Study Questions The following study questions were written by your fellow students, and at least one will appear on the next exam. Keep in mind that these questions focus on just a few topics and do not cover all the material that may appear on the exam. Thus you should not use this as a comprehensive study guide! 1. You have just graduated from Santa Clara. You are working for a consulting firm, and you have been assigned to study native populations in Africa where it is believed that a mysterious disease originated. The village you first come upon is relatively small (pop. 30). You and a colleague observe that mating is arranged in the village (arranged marriages within families), and after interviewing several inhabitants, you discover that no one has ever left the village and this is the first time that an outsider has been to the village in over 100 years. Your colleague asserts that the village is in Hardy-Weinberg equilibrium. Do you agree or disagree with your co-worker? Explain what you believe, utilizing the five points that define a Hardy-Weinberg equilibrium to support your argument. 2. On a southern Pacific island there is a population of wild goats that have variations in their fur length. Due to global warming the island's average temperature has risen 10 degrees. For this population it is more favorable for the animal to have less fur because it takes less effort to keep body temperature constant. In the next 100 years, what type of shift (stabilizing, directional, or disruptive) in the allele frequency will occur, and how will this change the population? If females selected mates where long fur was preferred, what would you need to know about the selection of this trait to determine how the allele frequencies would shift? 3. You are studying three tribes of humans. There are three different eye colors present in the populations: blue (bb), green (Bb), and brown (BB). The brown eye color allele (B) is incompletely dominant over the blue eye color allele (b) with the green eye color showing up in heterozygotes (Bb). After counting the eye colors of all the members of each of the three tribes, these are the data you have: Brown Tribe 1. Tribe 2. Tribe 3. 358 3080 65 Green 448 5480 8 Blue 194 1440 27 [Note that on an exam, numbers might be adjusted so that you could do the calculations without a calculator] A. Find the allele frequencies and expected genotype frequencies. B. Which of these are in Hardy-Weinberg equilibrium? C. What could possibly be affecting the third tribe to make the genotype frequencies so different from the other two tribes? Explain. 4. Unfortunately, due to the increasing levels of greenhouse gasses in the atmosphere primarily caused by the burning of fossil fuels by humans, the global temperature has reached a point where the glaciers located in the mountains of Utah have begun to melt. This spells bad news for a rare breed of red horned slugs who are unwittingly being surrounded by the rising and expanding waters of the Great Salt Lake. When the water levels finally reached the slug colony, the slugs found their population divided. One group, safe on high mainland ground well out of the way of the water contained an equal mix of the young, the old, males and females. The other group found themselves separated from the rest on a large island. Unfortunately, all the male slugs on the island, in a futile attempt to stop the rising waters, were swept up in the salty water, shriveled and died, leaving only females on the island. In a quick response, Al Gore successfully (and single-handedly) stopped global warming before any more damage could be done to these poor slugs. Explain why the slug population on the island has a much lower chance of surviving, assuming both populations are equal in size (these unique slugs can self-fertilize). Explain how inbreeding plays a major role in survival. Will mutation come into play? 5. You are a scientist studying different types of reproductive isolation. Your task is to take a series of examples and show if they are prezygotic or postzygotic isolation and what mechanism is responsible (timing, behavior, etc). A. Pine trees release pollen at time when another species' pine cones are inactive. B. One type of frog breeds only in the water, while the other breeds only on land. C. One type of tropical bird attempts to court a female of another species who doesn't recognize his courtship displays, so the two cannot reproduce. D. The gametes of two different species of fish cannot fuse due to a lack of compatible protein signals on the eggs. E. A Great Dane and a Chihuahua cannot mate naturally because of their difference in size. F. Two different but similar species of bird are able to reproduce but less than 10% of their offspring are viable. G. Horses and donkeys mate to produce viable mules, but they are born sterile. 6. Lonely Larry the zebra finch hasn't had a date in years. One day his professor explained the theory of sexual selection to him. The very next day Larry went out and bought a big bright orange plastic beak. Use the concept of sexual selection to explain why Larry might think that his flamboyant beak might help him meet female birds. How might the situation be different if Larry were a female bird? [Not part of the original question: Larry is cheating by buying a plastic beak. If many low-quality male birds bought bright orange artificial beaks, what do you think would happen to the evolution of this trait?] 7. A certain species of hippopotamus reproduces in the month of May. At this time, female and male hippos mate to produce offspring. During female pregnancy, male hippos provide the female with food and nutrients while the female rests in a swampy nest prepared by the male. After birth, the male hippos rear the child while the mother goes on to find another mate. Explain how and why the data collected for this population goes against the Bateman-Trivers principle. Sketch a graph comparing reproductive success to number of mates for both female and male hippos. 8. The Mario Brother series, the Koopa Troopas have different colored shells. When faced with their natural enemy, the Hammer Brothers, the best survival option is to withdraw into their shells. If survival is dependent on shell thickness (to withstand the hammers) and shell thickness is a heritable trait, and there is variety among individuals, will the population be subject to any trends? If so, what can we expect the next generation to look like? If the Mario Brothers take out the Hammer Brothers, what will happen to the population of Koopa Troopas then? 9. Suppose there are two evolutionarily independent species of squirrels, separated by a long, wide, winding river. These two species have different ancestors and have always been separate. One of the species, Squirrilius fuzzitonia, are characterized by their extremely furry tails, are notoriously friendly, and generally have a coat colored a shade of brown, ranging from light cocoa to dark chocolate colored. Since they are so anti-violence, they tend to eat grass and shrubbery. The other species, Squirrilius angeralos, are always a deep shade of black and tend to be quite aggressive. They hunt large insects and smaller rodents. however, over time, the river separating the two squirrel species gets dried up because of global warming, and the two isolated populations come into contact for the first time. What are four possibilities that can happen if the two isolated populations come into contact and begin to breed? Describe some of the consequences of each case. 10. During a rainstorm a nest of dragon eggs gets washed away and ends up in a completely different climate. These eggs hatch and start a new colony. A. Given that there was only one nest of five eggs that was transplanted during the rainstorm, what are some problems this colony might run into? B. After 100 years the dragons have chins that jut out. A new species of dragon shows up after a migration. They however choose not to mate with the jutty-chin dragons because they are so ugly. What do we call this? 11. Imagine that you are a botanist studying a species of flower, which you have named "ambers" because they are yellow. You have determined that the alleles for color in the flower are Y (dark yellow) and y (pale yellow), and that Y has incomplete dominance over y. These plants can self-fertilize or outcross. You have observed that caterpillars in the area tend to eat more of the light yellow flowers. The dark yellow flowers, however, are more likely to die in a drought, which you know from previous data. The weather between 1999 and 2007 has remained moderate, so there have not been any periods of drought or heavy rain. The following graphs and table demonstrate the patterns that you have noticed collecting data every odd year since 1999. A. Using the Hardy-Weinberg equation, fill in the grey boxes in the table below. Were there any years when the population fit the Hardy-Weinberg model? Genotype frequencies Yy 0.2 0.2 0.2 0.2 0 Allele frequencies Y y 1999 2001 2003 2005 2007 Observed Expected Observed Expected Observed Expected Observed Expected Observed Expected YY 0.6 0.8 0.4 0.5 0.5 yy 0.2 0 0.4 0.3 0.5 B. Which year do you think caterpillars were most abundant in the area? C. Compare genotype frequencies from the year when the most caterpillars were in the area, as well as frequencies from two years prior to that. Do these data show signs of natural selection? If yes, what type is it and how do you know? D. Do you see any instances of inbreeding? How do you know? 12. In recent classes we have discussed the idea of sexual selection. Sexual selection was discovered by observations that opposite sexes of the same species looked different and display unusual behavior. Sometimes these differences and behaviors can be detrimental to the organism's survival. So why is sexual selection evolutionarily possible even thought he phenotypic traits can be detrimental to their survival? ...
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This note was uploaded on 05/23/2008 for the course BIOL 22 taught by Professor Preston during the Winter '08 term at Santa Clara.
- Winter '08