Ecology 203, Exam II, Oct. 22, 1999 Name _______________________ Section I II
Rules: Read carefully, work accurately and efficiently. Note that you don’t have to answer all questions in each section. Good Luck!!! (note: SS = student submission)
Multiple Guess. Complete five. Circle the correct answer. (2 pts each)
a) competition
b) predation
c) disease
d) all of the above
e) none of the above
3. What is the most likely explanation for why Thomson’s Gazelles stot? [SS]
a) it is used as an alarm signal
b) it’s a form of social cohesion
c) they are trying to confuse the predator
d) they are trying to appear unprofitable
e) there appears to be no explanation for their behavior.
4. What is the equation for exponential growth rate? [SS]
a) N t+1 = Nt + r Nt (1-Nt/K)
b) Nt = lt No
c) Nt = No ert
d) all of the above are exponential
e) none of the above, they represent geometric growth
Guessing whether statements are true or false. Circle the correct answer (T for true; F for false). Complete five. (2 pts each)
Fill in the missing word or phrase. Complete five. (2 pts each)
Provide short answers for the following in the space provided. Complete three. (10 pts each)
1. Mark-recapture: You wish to estimate the population of small rodents in the Arboretum. You set out traps and catch 25 and mark them and then release them. You wait a week and set traps again. This time you catch only 20 and 7 are marked. What is your estimate of the small rodent population in this area?
2. Given that Nt = Noert and r = 0.1, how long will it take for a population of bunnies to grow from 100 individuals to 200 individuals?
3. Describe the four easily observed characteristics of natural selection that were first described by Darwin.
4. Why do modeling in science?
Graphing exercises. Label axes. Complete four. (10 pts each)
1. Below, graph the spatial distribution of regularly distributed individuals in a population:
2. Below, graph the relationship between population density as a function of body size for animals.
3. Below, graph exponential and geometric growth of a population as N vs. time (do this on the same graph).
4. Analyze the graph below. [SORRY, DIDN'T EXPORT TO EXCEL]
5. Based on the graph above, in the space below provide a graph of N versus time. Use the three starting populations given in the above graph (marks on the N axis). Assume those are initial populations (No).
6. Provide a graph of per capita growth rate (r) as a function of N for populations growing exponentially and logistically. Do this on the same graph.
7. Provide a graph of the relationship between territory size and body size. On this one graph provide the relationship for both predators and herbivores.