Biology 365 - Ecology Exam 2, Winter 1992 Please answer each multiple choice question on the sheet provided for you. Choose the best answer. Each multiple choice question in worth three (3) points. Please answer the essay question on the last page of the exam. 1. What is the numerical response to prey in Holling`s studies of predator/prey interactions? a. A change in predator behavior in response to prey density. b. A change in predator numbers in response to changes in prey density. 2. What is the effect of predator satiation on the number of prey killed? a. There is no effect. b. It increases the number of prey taken at high prey densities. c. It decreases the number of prey taken at high prey densities. 3. In Estes and Palmisano`s work on sea otters in Alaska, what did the presence of otters do to the shallow water marine communities? a. It removed all plant life. b. It caused a large number of sea urchins to colonize the site. c. It allowed kelp to grow because otters eat sea urchins which are major grazers on kelp. d. There was no difference between sites with and without otters. 4. How did the sizes of sea urchins from areas with sea otters compare with sizes of urchins in areas without otters? a. The ones in areas with otters were larger than urchins in areas without otters. b. The urchins in areas with otters were smaller than in areas without otters. c. There were really no size differences due to otter predation. 5. How do most freshwater zooplanktivorous fish select their prey? a. They filter feed all sizes from the water. b. They select individuals by catching what they see. These are the large ones. c. They select particular species independent of size. d. They select the slowest moving species. 6. What is the cause of the Lynx/hare cycles found in the Hudson`s Bay fur returns? a. Sunspots c. Indian hunting b. Lotka-Volterra oscillations d. We do not know 7. Poaching has greatly reduced the elephant populations in East Africa. What changes would you expect in the reproduction rate (per capita) and age structure of the remaining elephant populations? a. Reproduction should be high and the population should have lots of young animals. b. Reproduction should be low and the population should have lots of young animals. c. Reproduction should be low and the population should have lots of old animals. d. There will be no change in either factor. 8. What is the role of environmental heterogeneity in predator/prey interactions? a. It tends to destabilize them because it makes the prey easier to capture. b. It has no role because stability depends on characteristics of predators and prey - not the environment. c. It tends to stabilize them because it provides refuges for prey and allows for prey dispersal to predator-free sites. 9. Parvo virus is killing wolves on Isle Royale. If the wolves die out, what will be the likely effect on spruce tree reproduction? Spruce is a major winter food of moose. a. Spruce reproduction will go up. b. There will not be much effect at all. c. Spruce reproduction will decline because of poor seedling survival. 10. Keystone predators are: a. Top level predators whose activities organize the rest of the community. b. Very efficient predators. c. Predators that hunt one species to extinction. d. Predators that cause changes in communities. 11. The Illinois Department of Conservation introduces golden shiners (a fish) into lakes as food for bass. The golden shiner is a zooplanktivore. What will be its likely effect on lake zooplankton? a. It will shift the lake population toward larger body-sized species. b. It will shift the lake population toward smaller body-sized species. c. It will reduce the total number of individuals of zooplankton. 12. What species would most likely have the following survivorship curve in nature? a. Wildebeest on the Serengeti plains. b. Birds in Illinois woodlands. c. Mackerel in the Atlantic Ocean. d. Humans in Edwardsville. 13. What does the following survivorship curve mean? a. The population is dying out. b. The mortality of the population is concentrated in the early ages. c. There is a constant probability of death at any age. d. The individuals live to an old age and die. 14. You census a population in nature; it has a stable age distribution over the 10 years you census it. What can you say about the population. a. It is dying out. c. It is near carrying capacity. b. It has a constant growth rate. d. It has a high predation rate. 15. If you know an organism`s life-table, what can you calculate? a. r b. K c. dN/dt d. alpha and beta 16. What is a life table? a. A survivorship curve. b. A table showing age-specific mortality and age-specific fecundity. c. A mortality rate derived from banding or otherwise marking organisms. d. A table showing age-specific fecundity. 17. What was the conclusion of the density - dependent versus density dependent control controversy of the 1950`s? a. Ecologists concluded that density dependent controls are the only important ones. b. Ecologists concluded that different organisms live in different kinds of environments that impose dfferent mortality factors. c. Ecologists concluded that competition organizes all communities. 18. Andrewartha and Birch argued that the life history of Thrips imaginis shows that density independent controls are important in animal life. What was the response of the supporters of density dependence? a. Carrying capacity fluctuates in Thrips b. On a long term, Thrips follows density dependence. Andrewartha and Birch just haven`t looked at it long enough. c. Flowers are controlled by density independent factors -- not Trhips. 19. How could prudence evolve in predators? a. Individuals who are prudent would have more offspring than those who are not. b. Imprudent individuals would die out because they would eat up all of their prey. c. Prudent predators cannot evolve. The appearance of prudence is created because prey evolve to escape predation. d. Prudent predation has been a major force in the evolution of intelligence. 20. If a predator is prudent, what population level should he maintain in his prey? a. K b. Any number greater than 0. c. Enough prey so that they can reproduce. d. .5K 21. What kind of predator would have the following curve for number of prey killed versus prey density? a. Insect c. Vertebrate b. Filter feeder d. Parasitoid 22. Why does the curve in the previous question approach a constant at high prey densities? a. The predator`s filtering apparatus is clogging. b. The predator is switching to alternate prey. c. The predator is satiated. d. The predator is losing its search image. 23. If you are a fisheries manager and you find that the age distribution of the fish in a pond is skewed to old ages, what would you conclude? a. There has recently been a good year for reproduction. b. Environmental conditions in the pond have declined. c. You can`t conclude anything. d. Fishing pressure is intense. 24. What makes the construction of survivorship curves from bird banding difficult? a. Birds tend to lose bands. b. The data management is too difficult. c. Birds do not necessarily return to their birthplaces. d. You must band many individuals to get a statistically significant return. 25. What conditions favor the evolution of annual life histories in organisms? a. If the probability of adult survival from year to year is small. b. If the probability of survival of young past their first year is small. c. If the species generally has a stable age distribution. d. If the species lives in a good environment. 26. Which of the following characteristics should result in stable limit cycles between predators and prey? a. If the prey limit the predators and the predators limit the prey. b. If the prey and predators both have strong outside controls on their populations. c. If the prey have refuges. d. If the predators are very efficient. 27. If the prey and predator isoclines are as shown in the graph, what will happen to the populations? a. There will be stable coexistence. b. There will be stable limit cycles. c. Either one or the other will go extinct. 28. When Gause tested the Lotka-Volterra equations, he failed. Why? a. Didnium was just an inefficient predator. b. Paramecium was too good at escaping. c. Didinium was too efficient a predator and ate up all of the Paramecium. d. He used too much methylcellulose to slow the organisms down. 29. What did Utida`s experiment with wasps and Azuki Bean weevils show about the Lotka-Volterra equation? a. They have no validity whatsoever. b. If you choose the right organisms, you can get stable limit cycles. c. It is possible to get constant population numbers out of the equations. d. The wasp ate the bean weevils and starved to death itself. 30. The Kaibab Plateau deer study clearly shows that ungulate populations are limited by their predators. a. True b. False 31. (10 pts.) We are studying a very simple zooplankton community in a southern Illinois strip mine lake. The lake has no fish because it is acid. It has two species of zooplankton which replace one another in fall. Scapholebris lives through the summer and into fall. It is replaced by Brachionus. Design a series of experiments to test whether predation, competition, or simple physiological limitation causes this change of species. Remember that just because there are no fish in the pond doesn`t mean that there are no predators. Remember that just because there are n