BIO 321: Ecology Name: _______________________ Final Exam
Dr. C. Paradise Start time: _________________ Fall 2001
Instructions: The entire review is worth 200 points (13.33% of course grade) and will be due by 4 pm on Thursday, 12/13/01 in my office. No exceptions, and late reviews will result in a 5% deduction for each day it is late. You may not consult any references or any other person while working on this review. Your signature at the bottom of the last page signifies that the work is yours alone, was completed in four hours or less, and is pledged under the Honor Code. When you begin you will have a maximum of five hours to complete the review!
Confine your answers to the space below each question. Print legibly! Alternatively, the review may be done on the computer. You may type your answers to each question, and attach the printout to the review. Do not handwrite answers on separate pages! For each question or part to a question, limit your answers to one concise paragraph, unless otherwise specified. Lengthy typewritten answers will be penalized the same as lengthy handwritten answers!
1. What are two factors that limit primary production in aquatic ecosystems? (6 pts)
2. What is the difference between gross and net primary productivity? (6 pts)
3. Apply the concept of energy budgets to
a. Secondary production. (6 pts)
b. Population dynamics. (6 pts)
4. List three behavioral or physiological mechanisms by which organisms may adapt to pollutants in their environment. (9 pts)
5. Explain how the contrary theoretical diversity-stability conclusions of MacArthur and May can be reconciled. (10 pts)
6. Answer the following questions for the graph below (3 pts each – 9 pts):
a. What is the carrying capacity of this population?
b. Does this population show strong or weak density-dependence? Explain.
c. If the density of individuals in this population in year t is 10, then what will be the approximate density in year t+2? Will it always be thus, starting with xt = 10?
7. One of the earliest metapopulation models simply predicted the equilibrium probability that a particular population would persist for a certain period of time. That probability (p-hat) turns out to be [1 – (e/m)], where e = average rate of extinction of local populations of that species among all patches, and m = average rate of migration of individuals of that species among patches. Answer the following questions related to this model: (16 pts – 4 pts each)
a. Under what ecological conditions would the probability of persistence be equal to 0?
b. Describe, in one sentence each, one critical similarity and one critical difference between this model and the MacArthur-Wilson Island Biogeography Model.
c. List one extrinsic and one intrinsic ecological factor that might affect the rates of both extinction and migration for a species?
d. In one sentence, explain how population structure of a metapopulation might affect genetic diversity in a species?
8. The relationship between biodiversity (frequently measured as species richness) and ecosystem function (frequently measured as the rate of some ecosystem process) has often been found to be asymptotic. Draw a graph that represents this relationship and answer the questions on the next page. (15 pts - graph and questions are worth 5 pts each)
a. How does the curve above impact the argument that biodiversity should be conserved to maintain the functioning of ecosystems?
b. What relationship between ecosystem function and biodiversity would be optimal to use as an argument for species preservation?
9. On the surface, oscillations of populations of some forest Lepidoptera might be explained by intrinsic density dependent factors. Answer the following two questions about these insects. (12 pts total)
a. Explain how a predator-prey interaction might also explain this cyclic behavior. What is the hypothesized “predator” in this interaction? (7 pts)
b. Draw a graph showing a representative population growth curve of the lepidopterans and add in a curve showing what the population dynamics of the predator might look like. (5 pts)
10. Consider a species that exhibits strong density dependence. Describe, briefly, two life history traits that you predict it might display? (6 pts)
11. Explain fundamental and realized niche space as they relate to invasive species. (8 pts)
12. Show graphically how the patch model of optimal foraging leads to the prediction that shorter distances between patches leads to shorter foraging time within any one patch. Label all parts of your graph clearly. (8 pts)
13. List two physiological options that large mammalian hibernators have during hibernation or dormancy. Does any evidence exist that large mammals use either option? (8 pts)
14. In a population of deer, males are territorial only during the breeding season. During that time, individual males may or may not hold a territory, and regardless of possession of a territory, they may employ one of two strategies to defend or take over a territory: always attack (hawk) or always retreat (dove). (24 points total)
a. Fill in the values in the payoff matrix for attackers against each type of opponent, using the following rules: (8 pts)
Fitness points: +80 for winner, -100 for injury if attacked, -10 for display (no attack), 0 payoff for loser.
Other rules: hawks always fight, doves never fight but may display, hawk beats hawk 50% of the time, hawk always beats dove, dove beats dove 50% of the time.
| Attacker: |
Opponent |
|
| Hawk |
Dove |
|
| Hawk |
||
Dove |
||
b. Determine the probability of hawks in the population under an evolutionarily stable strategy (ESS). Hint: the average hawk payoff in the population is the payoff to hawks when they’re fighting hawks multiplied by the proportion of hawks in the population, plus the payoff when they’re fighting doves multiplied by the proportion of doves in the population. Same is true for doves. (8 pts)
c. What happens to the proportion of hawks when benefits to attacking exceed cost of injury? (4 pts)
d. When contesting a resource, an individual may employ different strategies. At the top of the next page, outline a scenario where an individual might employ a conditional strategy after assessing conditions. (4 pts)
15. The following is a graph of reproductive success in yellow-bellied marmots. What is the conflict that is represented here? (5 pts)
16. Consider the model: xt+T = xt * erT. (8 pts – 4 pts each)
a. What is the function that describes the rate of change of this model, and how does the rate of change vary with population density?
b. What value does r have to assume in order to have a negative growth rate? What about to have no change in population density over time?
17. Draw two possible population growth curves that can be obtained from the following model: f(xt) = er*(1-(xt/K)) * xt. Indicate which one has higher resilience. (9 pts)
18. Consider the model: xt+1 = xt + B*xt – D*xt. What one condition needs to be satisfied to produce the following curve? (4 pts)
19. In one sentence, why do nonequilibrium concepts often better describe ecological systems than equilibrium concepts? (5 pts)
20. Consider a species of deer-like mammal that inhabits forests in a fragmented landscape. Old growth forests are the preferred habitat type of this animal. This animal, which is a type of herbivorous large mammal, also has a polygynous mating system. Males have harems, and the size of the harem is dependent on size, age, and strength of the individual male. This species is in decline because of deforestation of old growth forests. A conservation plan for this species has been recommended that takes into account the metapopulation structure, the mating system, and genetics. Answer the questions regarding the plan. (20 pts – 5 pts each)
a. Not all old growth can be saved, and much of the forest is already fragmented. Ecologists recommend setting up populations of these mammals in second growth forest habitat. Explain why this might not be ideal.
b. Since many patches of old growth are either far apart or set apart by human-made barriers, what might ecologists have included in the plan to maintain high genetic diversity in these mammals?
c. It is recommended that calculations of effective population size be made using the number of all individuals in each local population, summed across all local populations. Give two reasons why this calculation severely overestimates NE.
d. Besides food for the mammals, what other type of organism has to be considered to predict the future health of our mammal population?
Nothing goes below this line except for filling in the blanks:
Time completed: ______________
Signature: ______________________________ Date: ___________________
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