Ecology 203, Fall 1998. Final Exam.

I will not discuss this exam with anyone who has not taken it.

Multiple Choice (2 points each). Answer all. Expect to spend about 45 minutes here. Please take your time!

1. Primary productivity is usually measured as
1. the number of animals in the community
2. the number of organisms the community supports
3. the mass of the plants in the community
4. the height of the vegetation
2. Net primary productivity equals
1. the difference between gross and raw productivity
2. negative and positive photosynthesis
3. primary consumption minus primary productivity
4. gross primary productivity minus respiration
3. Competition generally occurs most intensely between
1. members of the same species
2. members of related bud different species
3. members of unrelated species
4. none of the above
4. CAM photosynthetic pathway is used by
1. chemosynthetic bacteria
2. animals in the high arctic
3. cacti
4. deciduous trees under heat stress
5. Plant productivity, at least in many terrestrial ecosystems, is positively correlated with
1. herbivore consumption
2. herbivore biomass
3. herbivore productivity
4. all of the above
5. none of the above
6. The figure shows a steady increase in
1. the number of gypsy moth caterpillars
2. atmospheric CO2
3. sulfate released from hydrothermal vent ecosystems
4. nitrate input into the Hubbard Brook ecosystem

7. The research at Hubbard Brook experimental forest in New Hampshire provides good evidence that

1. acid rain negatively affects stream ecosystems
2. biogeochemical processes change little in forests over time
3. deforestation alters biogeochemical processes
4. global warming is likely to impact forests

8. Leaf litter decomposition rates
1. increase with increasing latitude
2. decrease with increasing moisture
3. increase with increasing nitrogen content
4. all of the above
5. none of the above

9. An autotroph is
1. an animal that finds its own food
2. an organism that makes its own sugars
3. an organism that moves around freely (without roots)
4. all of the above
10. The following are examples of omnivores:
1. cat, dog, wolf
2. tree, shrub, fern
3. human, bird, deer
4. raccoon, human, lobster
11. According to the 1960 paper by Hairston, Smith, and Slobodkin, the following factor(s) regulate herbivore populations:
1. food (therefore, competition)
2. predators
3. disease
4. density-independent factors
5. all of the above
12. To fully determine food-web links you should, if possible
1. observe everything that organisms actually eat
2. determine isotope levels in predator and prey tissues
3. conduct removal experiments to see how remaining organisms respond
4. all of the above
5. none of the above
13. The graph suggests that biomes
1. can be separated by temperature
2. can be separated by precipitation
3. can be separated only by both

factors simulataneously

4. cannot be separated

 

14. When trying to conserve a population (reduce its chance of going extinct) it is best to set up a preserve where the population
1. functions as a metapopulation
2. is as large as possible
3. is regulated by density-independent factors
4. has all predators removed
15. Higher latitudes (both north & south) are colder than lower latitudes (near equator) because
1. of El Niño
2. ice makes it cold
3. the circulation of the Earth’s atmosphere brings air from the tropics
4. the angle of the sunlight decreases at higher latitudes
5. the atmosphere is thinner at higher latitudes
16. Regulation of populations due to flooding represents what type of regulation:
1. density-dependent regulation
2. facultative apomictic regulation
3. density-independent regulation
4. extrinsic, biotic regulation
5. none of the above
17. An example of a physiological tradeoff is
1. plants grow more slowly when eaten
2. plants have to reproduce before they die
3. plants have to grow and reproduce
4. plants both grow and die
18. An organism's fundamental niche is usually
1. broader than its realized niche
2. more narrow than its realized niche
3. more important than its abiotic environment
4. none of the above
19. Theodosius Dobzhansky once said that nothing in biology makes sense except in the light of
1. ecological complexity
2. the sun
3. evolution
4. antagonistic pleiotropy
5. God
20. The classic example of hare and lynx populations oscillating, as discussed in lecture and not in the book, suggests
1. hare consumption of lynx varies over time
2. ecological systems are not always complicated
3. we should be careful about interpreting data
4. all of the above
21. Frank Egler, rebel ecologist, provided probably the best model of community development over time. This was the
1. initial floristic composition model.
2. relay floristics model.
3. idea of natural selection.
4. individualistic concept.
22. Small populations are at risk of going extinct because
1. individuals have difficulty finding each other (Allee effect)
2. homozygosity increases
3. inbreeding increases
4. all of the above
5. non of the above

True/False. Fill in "A" for TRUE, "B" for FALSE ON ANSWER SHEET. If the statement is true it will be true under all possible conditions that fall within the scope of the statement. If it is true most of the time but false occasionally, the statement is false. If you think the statement seems incomplete then it is probably false. I recommend graphing, if possible, any statements you find confusing. Answer all. Take a half hour. (2 points each)

23. Frederic Clements believed that communities develop over time just like individual organisms develop over time.
24. Plant productivity is influenced by the amount of solar radiation reaching the leaves.
25. C4 photosynthesis yields a four carbon molecule while C3 yields a three carbon molecule
26. Plants increase photosynthetic efficiency with decreasing water levels.
27. Tropical forests, on average, have higher net primary productivity rates per unit area than oceans.
28. The huge amount of land area, high solar input, and low cloud cover allow deserts to have gross primary productivity rates that are nearly twice the rates of tropical forests.
29. The Sustainable Biosphere Initiative (SBI) is a call for ecologists to not only conduct basic research but also to get involved with public education and management decisions regarding ecological systems.
30. Only about 25% of the radiation reaching a boreal forest canopy actually makes it to the forest floor.
31. Despite its ill effects on worldwide climate, the warming of the equatorial Pacific waters (El Niño) increases that area’s phytoplanktonic productivity.
32. Biogeochemical cycles are miss-named because it actually is energy that cycles through ecosystems.
33. The level of herbivore damage to leaves can influence the rate at which those leaves decompose.
34. The amount of biomass in trophic levels, starting from producers and going up through consumers, looks like a pyramid, with the greatest amount of biomass found in producers and the least amount of biomass found in predators.
35. Time to extinction generally increases with increasing population size.
36. Populations growing exponentially can, despite this growth, exhibit a stable age distribution.
37. During forest succession tree volume and biomass increase while the number of trees decreases, a relationship referred to as both the "self-thinning law" and the "-3/2 law."
38. Shelford’s "law of tolerance" suggests that species go extinct as quickly as new species arise through evolution.
39. When populations are modeled using the "logistic equation" the number of organisms starts off increasing exponentially but then levels off to a stable equilibrium. (Recall the lecture on this.)
40. Competitive ability and colonization ability are usually inversely related (i.e., form a tradeoff).

Short answers. Answer the following 4 questions to the best of your ability. Be sure your answers are complete. Allocate about 15 minutes each. Plan before you write! (5 points each)

1. The two graphs represent the number

of species of birds (top) and mammals (bottom) on

mountain tops in the Great Basin. Interpret the

significance of the graph. Axes are the same in

both graphs. The equations are not very important

since axes' units are the same. The y-axes show the

number of resident species; the x-axes show the

area above 2300 m.

3. Why should we give a hoot about human-induced climate change?