Principles of Ecology, Exam 2 Page 1 of 9

Exam 2. Principles of Ecology. April 6, 2011. Name ________________________________________

This exam has 100 points with 6 extra credit points possible. I apologize for not asking questions that you knew

the answers to! Many important topics have been overlooked. I apologize for this! Here are some useful

equations that might be referenced in the exam. (Note to finish on time take at most 30 secs / point)

Nt = Not Nt = Noe

rt Nt+1 = Nt + roNt(1-Nt/K) Nt = K/(1 + [(K – No)/No] * e

–rt)

dN/dt = rN(1-N/K) Ncaptured and marked initially = Nmarked at recapture

Ntotal Ntotal recaptured

dS/dt = - β SI – dS + R dI/dt = βSI – vI – dI - I dR/dt = vI – dR - R

dH/dt = rH – cHP dP/dt = acHP –dP dP/dt = mP(1-P) – eP

dN1/dt = r1N1(K1 – N1 – 12N2)/K1 dN2/dt = r2N2(K2 – N2 – 21N1)/K2 Nt+1 = (so B + sa) Nt

C = L/[S(S-1)/2]

Use the ScanTron for these multiple guess questions (4 pts each,40 pts total).

1. The population of wolves in Yellowstone went from 137 to 121 in one year. What was r if the population grew

according to the exponential growth during this time? Which of the following is the closest estimate for “r”

during this time period?

a.

b. -0.08

c.

d. 0.88

e. None of the above. I got __________________

2. If a population has a spatial dispersion pattern that yields a variance:mean ratio (s2/mean) = 1.5 and a X2 test

yields p = 0.01 then our best interpretation would be that our population dispersion pattern is

a. random.

b. clumped.

c. uniform.

d. still unknown.

e. unknowable.

3. A stream has the following numbers of individuals in each of four species: A = 10, B = 20, C = 30, D = 40. Which

is the best description of the stream's diversity?

a. H' = 1.28

b. H' = 0.56

c. Species richness = 4

d. H' = 0.91

e. There are four species with 100 individuals

4. Which of the following is the best answer to why many "neo-tropical migrant birds" migrate to western NY for

the summer?

a. There are more potential mates here than in the tropics.

b. Nesting sites are more abundant here than in the tropics.

c. They are escaping nest predators, such as monkeys and snakes.

d. All of the above are the best reason for the migration.

e. None of the above. Birds have always migrated in the past.

Principles of Ecology, Exam 2 Page 2 of 9

5. Which of the following is your best estimate for a population of animals if you first capture 25 animals, mark

them, and then release them and a week later you capture 33 animals and find 5 are marked?

a. 7.

b. 38.

c. 63.

d. 125.

e. 168.

6. If the human population is 6.90 billion people now and r, as we estimated it based on real data, is 0.00692, what

will the population be in 100 years, assuming it is growing exponentially and r remains unchanged?

a. 6.95 billion.

b. 13.09 billion

c. 13.78 billion

d. 14.47 billion

e. We do not have enough information.

7. Which of the following is a correct matching of community development theory and scientist?

a. Individualistic concept………………………………………. Gleason

b. Organismal concept, or "relay floristics"……………………. Egler.

c. Initial floristics composition model………………………….. Clements.

d. All of the above are correctly matched.

e. None of the above are correctly matched.

8. In a very recent "What's new?" discussion we learned of an interaction between two species of Streptococcus

bacteria in our mouths. One of the species creates biofilms on our teeth, the other does not. Which of the

following best describes the interaction between these bacteria in our mouths (abstract in lecture and notes, too)?

a. competition

b. predator-prey

c. parasites/pathogens

d. commensalism

e. amensalism

9. Given the model to the right which equilibrium point will the

current population (solid dot) end up at?

a. point a.

b. point b.

c. point c.

d. point d.

e. the point is already in equilibrium.

Principles of Ecology, Exam 2 Page 3 of 9

10. Thomas Park's work on competitive interactions between two species of flour beetles is summarized below.

Which of the following statements best identifies the significance of this work? (A "think" question – couldn't

memorize this!):

a. ecological systems are simply too complex to understand.

b. competitive exclusion between two closely related species is inevitable.

c. competitive coexistence is possible if the competitors are different species.

d. competitive coexistence would be possible if environmental conditions fluctuated.

e. competition is a stochastic process; winning is much like gambling.

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Mandatory 5 point question.

1. Describe the four easily observed characteristics of natural selection. (5 pts, -2 pts for first wrong)

a.

b.

c.

d.

Principles of Ecology, Exam 2 Page 4 of 9

Age N0 N

1 N

2 N

3

Na 10 30.0 12.0 18.5

Nb 10 5.0 15.0 6.00

Nc 10 3.5 1.75 5.25

Mandatory 15 point question.

1. In the diagram please provide (15 pts)

a. the values that belong in each of the 9 cells of the Leslie matrix (5 pts).

b. complete the model projection into the future (5 pts), and

c. calculate the values of . (5 pts)

If you can't do part "a" then use the filled in values for the given matrix.

If you can't do part "b" then use the values given below for a hypothetical population.

If stuck proceed with the following values for parts "b" and "c" (without points for a and b, respectively).

USE IF YOU CAN'T DO PART a USE IF YOU CAN'T DO PART b

Principles of Ecology, Exam 2 Page 5 of 9

10 Point questions – Choose ONE on this page

1. The graph on the left is a model of a single population which has no immigration or emigration.

Analyze the graph on the left (5 pts). On the right, graph N vs. time for each of the four starting points

which match to points on the x-axis in the graph on the left (5 pts). (10 pts total)

2. Regarding the SIR mathematical model from the front page (and from your R module, lecture, and your

text), create a phase-plane graph for "I" vs. "S". Assume S = 999, ST = 500, I = 1, and R = 0. I've provide

two sets of axes. One is for practice (left) and one will be your "final answer" (right). Label axes (2 pts

ea.), provide your starting point (2 pts), and the trajectory (4 pts). (10 pts total)

Practice Graph Here's your "final answer":

Principles of Ecology, Exam 2 Page 6 of 9

Five Point Questions – Choose ONE on this page.

1. Provide a graph of the approximate relationship between the maximum per-capita growth rate for

organisms and the mass of the organisms at adulthood. Identify at three groups of organisms in your

graph. Label your axes (1 pt each), and your three groups in the correct relationship (3 pts). (5 pts total)

2. Draw the theory of island biogeography for a small, far away island. Analyze the graph. Label your axes

(1 pt each), draw the theory (2 pts), and analyze the graph (1 pt). (5 pts total)

Principles of Ecology, Exam 2 Page 7 of 9

10 Point questions – Choose ONE on this page

1. We discussed the -3/2 Law a few times. Provide a graph of this relationship using realistic data (2 pts for

each axis label, 2 pts for correct relationship). Briefly describe an experiment that test this relationship

(4 pts). (10 pts total)

Describe an experiment that would result in

getting the data that would test this law.

2. We discussed a variety of ways that prey avoid predators and predation. Huffaker investigated this using

arrays of oranges with herbivorous and predator mites. Draw the original Lotka-Volterra model that he

started with and show a second graph of how he manipulated this model to achieve a dynamic

coexistence between predators and prey.

Before After

Principles of Ecology, Exam 2 Page 8 of 9

I. ANALYZE THE GRAPH and answer the questions. (15 pts)

1. Identify the points as either not an equilibrium point (NE) or which kind of equilibrium they are (LSE,

USE, or GSE). (1 pt each)

a. point a: _________________________________________________________________

b. point b: _________________________________________________________________

c. point c: _________________________________________________________________

d. point d: _________________________________________________________________

e. point e: _________________________________________________________________

3. What do the following lines represent (provide an equation or written description)? (1 pt each)

f. line f: ______________________________________________________________________

g. line g: ______________________________________________________________________

h. line h: ______________________________________________________________________

i. line i: ______________________________________________________________________

4. Provide the entire trajectory of the solid point on left to its equilibrium, assuming it adheres to the

model. (2 pts)

5. Draw the numbers of N1 and N2 on the right graph to their equilibria, assuming they start at the big, solid

point in the left diagram. Assume the scales for N1 and N2 are the same. (2 pts each, 4 pts total)

Principles of Ecology, Exam 2 Page 9 of 9

Extra Credit (6 pts possible)

1. What was the controversial proposal that was recently put forth regarding the management of introduced species

in the Galapagos? (1 pts)

2. What non-human North American land animal did I suggest could commute to Rochester under its own power? (1

pt)

3. Describe the latest research (that we discussed) on the effect of contrails on global climate. (1 pt

4. Which of the following men devised the "multidimensional hyperspace model" of niches? (1 pt)

b. Lord Robert May

c. Evelyn Hutchinson

d. Leslie (of Leslie matrix fame)

e. It is still to be proposed

5. Calculate the connectance (C) of the food web. (2 pts)

C =