Review for Final Exam
Only a sample of these questions will be included in the final exam. I reserve to right to ask one ‘joker’
question – i.e. one question not in the list below.
1. The variety of microorganisms that live on your teeth have an ecology like any other community. What do
you think might be the similarities in the forces determining species richness (the number of species
present) in your oral community as opposed to a community of seaweeds living on boulders along the
shoreline?
2. Why do some temporal patterns in ecology need long runs of data to detect them, while other patterns
need only short runs of data?
3. Discuss the advantages and disadvantages of descriptive studies as opposed to laboratory studies of the
same ecological phenomenon.
4. What is a ‘natural field experiment’? Why are ecologists keen to take advantage of them?
5. In a study of stream ecology, you need to choose 20 sites to test the hypothesis that brown trout have
higher densities where the stream bed consists of cobbles. How might your results be biased if you chose
all your sites to be easy to access because they are near roads or bridges?
6. How might the results of the Cedar Creek study of old-field succession have been different if a single field
had been monitored for 50 years, rather than simultaneously comparing fields abandoned at different
times in the past?
7. When all the trees were cut in a Hubbard Brook catchment area, there were dramatic differences in the
chemistry of the stream water draining the catchment. How do you think stream chemistry would change
in subsequent years as plants begin to grow again in the catchment area?
8. What are the main factors affecting the confidence we can have in predictions of a mathematical model?
9. What do you consider to be the essential distinction between natural selection and evolution?
10. Why is the ‘survival of the fittest’ an unsatisfactory description of natural selection?
11. What is the essential difference between natural selection and the selection practiced by plant and animal
breeders?
12. What are reciprocal transplants? Why are they so useful in ecological studies?
13. In what ways do ectotherms and endotherms differ, and in what ways are they similar?
14. Describe the interaction of plants’ requirements to increase the rate of photosynthesis and to decrease the
rate of water loss. Describe, also, the strategies used by different types of plants to balance these
requirements.
15. Why are deserts more likely to be found at around 30 degrees latitude than at other latitudes?
16. Describe the various changes in climate that occur with changing latitude
17. Biomes are differentiated by gross differences in the nature of their communities, not by the species that
happen to be present. Discuss possible schemes for the objective classification of gross differences among
floras and faunas that can be used to distinguish among biomes.
18. The tropical rain forest is a diverse community supported by a nutrient-poor soil. Why?
19. Which of the Earth’s biomes do you think have been most strongly influenced by people? How and why
have some biomes been more strongly affected by human activity than others?
20. What is meant by the ‘stratification’ of water in lakes? How does it occur? And what are the reasons for
variations in stratification from time to time and from lake to lake?
21. Describe how the logging of a forest may influence *the community of organisms* inhabiting a stream
running through the affected area.
22. Why is much of the open ocean, in effect, ‘a marine desert’?
23. Discuss some reasons why community composition changes as one moves (1) up a mountain and (2) down
the continental shelf into the abyssal depths of the ocean.
24. Why are broad geographic classifications of aquatic communities less feasible than broad geographic
classifications of terrestrial communities? What characteristics of aquatic ecosystems buffer the effects of
climate?
25. In a mark-recapture exercise during which a population of butterflies remained constant in size, an initial
sample provided 70 individuals, each of which was marked and then released back into the population.
Two days later, a second sample was taken, totaling 321 individuals of which 74 bore a mark from the first
sample. Estimate the size of the population. State any assumptions that you have had to make in arriving
at your estimate.
26. Define annual, perennial, semelparous, and iteroparous. Try to give an example of both an animal and a
plant for each of the four possible combinations of these terms. In which cases is it difficult (or impossible)
to come up with an example and why?
27. Contrast the derivation of cohort and static life tables and discuss the problems of constructing and/or
interpreting each.
28. Describe what are meant by aggregated, random, and regular distributions of organisms in space, and
outline, with actual examples where possible, some of the behavioral processes that might lead to each
type of distribution.
29. Explain why an understanding of life-history trade-offs is central to an understanding of life-history
evolution. Explain the contrasting trade-offs expected to be exhibited by r-selected and K-selected species.
30. Some experiments concerning interspecific competition have monitored both the population densities of
the species involved and their impact on resources. Why is it helpful to do both?
31. Explain how environmental heterogeneity may permit an apparently ‘weak’ competitor to coexist with a
species that might be expected to exclude it. Use example(s).
32. True predators, grazers, and parasites can alter the outcome of competitive interactions that involve their
‘prey’ populations: discuss this assertion using one example for each category.
33. Predation is ‘bad’ for the prey that got eaten. Explain why it may be good for those that do not get eaten.
34. With the help of an example, explain why most prey species can be found in communities subject to an
intermediate intensity of predation.
35. What human activities are clearly unsustainable?
36. Why exactly is the human population problem?
37. Why is there a disagreement on the ultimate carrying capacity of the world – with regards to the human
population?
38. Describe some of the large-scale problems that have arisen due to monoculture. Be sure to describe and
not just list.
39. Describe, in detail, the major global pathways of nutrients in these cycles:
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Phosphorous Cycle
Nitrogen Cycle
Sulfur Cycle
Carbon Cycle
40. The hydrological cycle would proceed whether or not a biota was present. Discuss how the presence of
vegetation modifies the flow of water through an ecosystem.
41. Hilborn and Walters have suggested that there are 3 attitudes that ecologists can take when they enter the
public arena. The first attitude is to claim that ecological interactions are too complex, and our
understanding and our data too poor, for definite pronouncements to be made – for fear of being wrong.
The second attitude is for ecologists to concentrate exclusively on ecology and arrive at a recommendation
designed to satisfy purely ecological criteria. The third attitude is for ecologists to make ecological
recommendations that are as accurate and realistic as possible, but to accept that these will be
incorporated with a broader range of factors when management decisions are made -and may be rejected.
QUESTION: which of these attitudes do you favor – and WHY?
42. Explain, with examples, how the loss or introduction of a single species can have conservation
consequences throughout a whole ecological community?
43. Are there any circumstances where the intentional introduction of an exotic species can be considered a
good thing because it enhances biodiversity? Explain.
44. What is meant by a "monoculture". State one major advantage and one major disadvantage and describe
them briefly.
45. Discuss what is understood about the relationship between the complexity and stability of food webs.
46. It may be said that biomes occupying the extremes of the precipitation spectrum (very moist or very dry)
burn infrequently, but that those with moderate precipitation and seasonal drought burn readily and
regularly. Please explain this phenomenon.
47. Why does assimilation efficiency vary so widely among different kinds of animals?
48. What are the impacts of eating ‘low on the food chain’?
49. Discuss at least two guidelines for humans to consider if they wish to live in harmony with the natural
world.
50. What are the consequences of fragmentation on natural reserves?
51. How has this class changed your outlook, if at all?
52. Using what you have learned about ecology, describe why it is important to protect natural ecosystems
and other species.
53. Because new species will eventually evolve to replace those that humans are driving to extinction, why is
declining biological diversity such a threat to us?
54. The world today is starting to envision a sustainable society, one in which each generation inherits
sufficient natural and economic resources and a relatively stable environment. In Lebanon, in what ways is
our current system not sustainable? What might we do to work towards sustainability? What are the major
road blocks to achieving it? How would your life be different in a sustainable society?
Questions from a student:
1) what has ecology taught us?
2) how could you ecologically benefit the Lebanese public health?
3) if you want to build a healthy ecological community what would you do?
4) how did this course change your perception and behaviours and why ?