Ecology 203, Exam I, March 1, 1999 Name _________________________ (1 pt extra credit, spelling counts)

Rules: Read carefully, work accurately and efficiently, place longer answers in blue book. I recommend marking the questions you want to answer before you begin writing. If you get stuck on a question move on and return if you have time. The last question will take some time and is worth 20 points so plan ahead.

Good Luck!!!

1. A problem in physiological ecology might involve determining
1. why lions commit infanticide
2. why dandelions defend themselves
3. how lions deal with the heat of mid-day.
4. the size of a lion population
2. An example of a physiological tradeoff for plants occurs when they have to either
1. grow or die
2. defend themselves or die
3. defend themselves or grow
4. all of these
5. none of these
3. An example of an abiotic constraint on organisms, potentially leading to density-independent regulation, is
1. a rare drought event
2. competition
3. predation
4. all of the above
5. none of the above
4. What information below would allow you to best predict what the vegetation might look like in any particular place on earth:
1. yearly rainfall
2. yearly average temperature
3. soil depth
4. yearly rainfall and yearly average temperature
5. soil type and predator community
5. A population with r = 0.5 (recall dN/dt = rN which, when solved yields N_t = N_o e ^rt) is
1. increasing
2. decreasing
3. oscillating
4. all of the above
5. none of the above

1. T F The overlap of fundamental niches between two species means these two species are competing.
2. T F Plant photosynthetic pathways are determined entirely by the amount of rainfall.
3. T F Populations can increase exponentially and yet maintain a constant ratio of old to young individuals.
4. T F Fish in oceans need to drink water.
5. T F Camels use their humps to store water.
6. T F Not all communities are dependent on energy from the sun, captured through photosynthesis.

Science Predator Functional Response

Biodiversity "Hot Spot" Logistic Growth

1. Why do seasons change?
2. I discussed several characteristics of niches. Discuss two characteristics in detail.
3. I presented the data below in class. What is the interpretation of these data?

4. Animals often visit a variety of feeding areas during each day. Assuming that an individual animal enters a random patch what do you expect their net energy gain looks like as a function of time spent in the patch (residence time)? Graph the relationship, labeling your axes very clearly, AND briefly describe why you think this is what the graph looks like.
5. What are the four, easily observed characteristics that constitute natural selection. Briefly discuss each.
6. Last week I found this quote in the NY Times: "At that time [back in the 1970’s], it didn't matter what [disease] human beings got, because we could always pump them with antibiotics. We don't have that luxury anymore." Why not? Please explain your answer.

7. What is the significance of this graph to the

mechanism of natural selection? (Hint: two

characteristics are satisfied.) Explain and,

if you have to, draw (literally) on the graph and

refer to your marks in your answer.

 

 

 

 

 

 

 

 

 

 

 

 

 

8. Explain what is meant, using an example, by the statement "there is usually an interaction between resources." A graph would likely help your answer.
9. You are interested in estimating the size of a small, hard to see rodent population. You set out traps, collect 50 individuals, and mark them. You come back one week later and resample. In your recapture of a sample of these rodents you find 25 of the 100 captured are marked. In an audience with an omnipotent being you are told that your estimate is a little low. What was your estimate AND what might have happened to lead you to underestimate the population. (Recall N marked at t₁/N_total = N_{marked t2}/N total captured at t₂.)
10. Graph the number of individuals in a population against time. Assume that the population begins at 1000 individuals and continues for 10 years and changes in a discrete, geometric fashion with l = 0.75 (Recall that N_t+1 = l N_t). Calculate the size of the population for each of the 10 years (some rounding is acceptable) and draw a graph of your data. Label your axes completely. Why might a population behave this way?

Mandatory (20 points)

Write a question you think should have appeared on this test but didn’t and answer it. You will be graded on the creativity of the question, its difficulty, and your answer. I recommend it not be too difficult because you have to answer it. I’d avoid an easy T-F question, despite the high likelihood of getting the correct answer. Requiring a graph or discussion of real data encountered in lecture or the book is fair.