Ecology 203, Exam III, Nov. 22, 1999 Name _____________________ Section I II
Rules: Read carefully. Work efficiently. Do only the number of questions that you are asked to complete in each section. CIRCLE QUESTIONS YOU WANT GRADED. SS = Student Submission
Multiple guess. Choose the single best answer for five. 2 pts each
1. The community development hypothesis, which states that individuals within communities all start at the same time but their dominance occurs at different times which leads to succession in a community, was proposed by [SS]
a. Clements
b. Gleason
c. Egler
d. Darwin
e. none of these folks
2. What was the purpose of the defaunation experiment on the islands of the Florida keys? [SS]
a. To observe colonization of arthropods
b. To observe trophic cascades
c. To observe the effect of changing species pools on colonization and extinction
d. To observe the effect of latitudinal gradients
e. All of the above
3. The performance of a plant, determined in the experiment by Hartvigsen et al. (1995) depended on [SS]
a. fertilizer
b. herbivores
c. herbivore predators
d. all of the above
e. only b and c
4. Nancy Johnson's experiments determined that [SS]
a. mycorrhizal fungi are mutualistic on low nutrient soils but relatively parasitic on high nutrient soils
b. mycorrhizal fungi are mutualistic on high nutrient soils but relatively parasitic on low nutrient soils
c. altering the nutrient environment doesn't influence the mutualistic relationship between plants and mycorrhizal fungi.
d. all of the above statements are true
e. parasitic plants, such as mistletoe, induce elevated hormone levels in mice
5. Which of the following is not a characteristic of an organism’s niche? [SS]
a. time (e.g., time of day)
b. spatial location
c. asymmetry
d. resource requirements
6. Which of the following is an example of a mutualism: [SS]
a. ants/acacia trees
b. bees/flowers
c. mycorrhizae/plant roots
d all of the above
e. only a and b
7. Which of the methods below, used to test the presence of competition, is best:
a. look for patterns of reduced individual performance consistent with competition.
b. remove all individuals in an area and see what happens.
c. add fertilizer to plants and see if they grow and reproduce more.
d. kill individual plants with a deadly herbicide and see if the remaining plants produce more seeds.
e. perform any one of these experiments because they all are equally good at testing the presence and importance of competition.
8. Disease agents, like the viral pathogen that kills spruce bud moths, often require
a. only a single individual host for long-term persistence in a population
b. a threshold number of individuals to become established
c. variability, acted on by the process of evolution, to control a host population
d. an Ro > 0 to spread
e. all of these are requirements of disease agents.
9. Studies of bioaccumulation of toxic compounds in food webs have provided us
a. a better understanding of how food webs function
b. information on the hazards of persistent chemicals in our environment
c. with insight on how fragile top predators can be because they tend to concentrate persistent chemicals.
d. all of the above
e. none of the above.
True/False. Circle T for true and F for false. Answer five. 2 pts each.
1. T F Predator satiation is found in some plants and animals as a defensive tactic that results in decreased risk of death to individuals due to predation. [SS]
2. T F Plants that produce defensive compounds do so either always (constituent; always present) or upon attack (induced). [SS]
3. T F The smaller the value of the Shannon-Weiner index, the larger the difference in proportion of species in the community. [SS]
4. T F According to the Theory of Island Biogeography, near islands are colonized at a lower rate than the islands further away. [SS]
5. T F Species diversity must be homogeneously distributed in either time or space. [SS]
6. T F Community development in the Roemer Arboretum over the past 30 years is an example of primary succession. [SS]
7. T F Estimates range up to 96% of all species that went extinct at the end of the Cretaceous period (when the dinosaurs went extinct). [SS]
8. T F Pathogens that harm their host (are highly virulent) are selected against by natural selection so that, over time, diseases evolve toward the state of "benign coexistence" and may eventually become mutualists.
9. T F According to Hairston, Smith, and Slobodkin (1960), plants, herbivores and predators are regulated by competition, enemies, and competition, respectively.
Definitions. Define any two terms. Provide a graph when possible. 5 pts each.
Exaptation Landscape Ecology
Resource Availability Hypothesis (or theory) Fractal Geometry
By-product mutualism Diversity
Community stability
Place short answers in blue book, unless otherwise instructed. Choose any three. Provide a graph when possible. 10 pts each.
1. Why is the world green? [SS]
2. Discuss the two main types of plant defenses. [SS]
3. Graph the "Herbivore Optimization Hypothesis" and state it's significance. [SS]
4. Graph & discuss the intermediate disturbance hypothesis [SS]
5. Briefly compare "response to competition" and "asymmetry" with regards to their measurement and meaning in ecology.
6. Describe the concept and characteristics of a species’ niche.
7. Explain how oak trees can influence the prevalence of both Lyme disease and the disease that kills gypsy moth caterpillars (nuclear polyhedrosis virus). Provide a diagram.
8. Describe how you would ideally build an accurate food web diagram. Provide a graph.
9. Discuss the significance of the following graph:
10. Provide a graphical analysis of the "Theory of Island Biogeography."
11. Discuss the pros and cons of models at both ends of the complexity spectrum: from exponential growth (dN/dt = rN) to the individual-based, evolutionary model that I presented of population and community dynamics.
Mandatory short answers. Analyze = identify equilibria and indicate whether or not they are stable, and label all lines (e.g., isoclines). Answer all four. 10 pts each.
1. Analyze the following graph. (It was N1 vs. N2 competition isoclines)
2. In the space below provide a single graph of N as a function of time for both species in the above graph. Start your populations at the point shown in the above figure. Analyze your graph.
3. Analyze the above graph. (This was a predator-prey graph with prey exhibiting the Allee Effect and density dependence while the predator isoclined exhibited only density dependence.)
4. Provide a single graph below of N as a function of time for both predators and prey, starting at the point provided in graph above. Analyze your graph. Label lines for P and H.