Ecology 203, Exam I, October 14, 1998 Name ______________________________ (1 pt, spelling counts)

Rules: Read carefully, work accurately and efficiently. Answer all questions to the best of your ability. If you get stuck on a question move on and return if you have time. Good luck!

Multiple Choice. (Circle the one correct answer). (3 pts each; 24 pts total)

1. Relative to populations of equal size in a single habitat, metapopulations are

    1. more likely to exhibit positive assortative associations
    2. less likely to go extinct
    3. characterized by aposematic coloration
    4. organized into complex social systems
    5. none of the above

2. Introduced species: (submitted by fellow student)

    1. are mostly the result of humans
    2. usually spread rapidly
    3. always have high r and broad niches
    4. all of the above
    5. none of the above

3. The change in seasons is due to:

    1. the presence of our moon
    2. the rotation of the Earth on its axis
    3. the revolution of the Earth around the Sun
    4. the tilt of the Earth’s axis
    5. human-induced climatic variability

4. Higher latitudes (both north & south) are colder than lower latitudes (near equator) because

    1. the angle of the sunlight decreases at higher latitudes
    2. of El Nino
    3. ice makes it cold
    4. the circulation of the Earth’s atmosphere brings air from the tropics
    5. the atmosphere is thinner at higher latitudes

5. Evolution, the change in gene frequencies over time, occurs by:

    1. natural selection
    2. gene flow
    3. genetic drift
    4. all of the above
    5. only "a." above

 

6. Sexual dimorphism is caused by (submitted by fellow student)

    1. sexual selection
    2. allopatric speciation
    3. gene flow
    4. all the above
    5. none of the above
    6. only a and c

7. The change in density of a chaotic population is (submitted by fellow student)

    1. unpredictable and lacks pattern
    2. predictable and lacks pattern
    3. unpredictable with a pattern
    4. predictable with a pattern
    5. likely to lead to fortune on the stock market

8. The following is not an assumption of the Hardy-Weinberg Law: (submitted by fellow student)

    1. High mutation rate
    2. No selection
    3. Generations do not overlap
    4. Random mating
    5. None of the above (they all are valid assumptions)

True-False – circle T for true, F for false (3 pts each; 15 pts total).

T F Natural selection, the most important mechanism leading to evolution, can be observed in our lifetime.

 

T F Populations comprised of "r-strategists" grow and reproduce quickly. (submitted by fellow student)

 

T F Poikilotherms have no mechanisms to control their body temperature.

 

T F Populations that exhibit source-sink dynamics are in decline (population is decreasing).

 

T F Andrewartha and Birch studied a thrips population and concluded that the population was regulated primarily by weather. They did acknowledge, however, that some biotic factors may operate at times but that, in general, abiotic factors explained most of the variance in their multiple regression model used to predict population numbers.

 

Graph the relationship between realized population growth (dN/dt) and population size (N) under density-dependent regulation. Include the Allee Effect and identify all equilibrium points as stable or unstable. Label the axes. (5 pts)

 

Short answer (Complete TWO of the three): (6 pts each; 12 pts total)

1a. Given that you know Nt = No e rt, r = 0.01 annually, and that No for an insect population today is one hundred individuals. Assuming annual reproduction with non-overlapping generations what will the population be in 100 years?

 

 

1b. How many years does it take for this population to double in size (or when will Nt = 2 No assuming you know Nt = No e rt)?

 

2. A population has the following life table:

X lx bx

0 0.5 1

1 0.0 1

and No = 10, N1 = 5

Plot the number of individuals in both age

classes 0 and 1 over then next three years.

 

3. What are the four, observable characteristics of natural selection?

 

Short answer (Choose any FOUR of the following six questions): (3 pts each; 12 pts total)

1. Describe the mark-recapture method for estimating population size (the equation is required).

 

 

2. Why are models are useful in ecology?

 

 

3. Give an example of something that exhibits a stabilizing type of selection. (submitted by fellow student)

 

 

4. What are the constraints on the number of eggs laid by female birds (briefly discuss constraints for both low and high egg production).

 

 

5. What are some of the problems faced by organisms in high (or low – you choose) temperature environments? (submitted by fellow student)

 

 
  1. Graph the standard species-area relationship. Do not log-transform axes. Label the axes.

 

 

Define any TWO of the following (identify those you are defining). (5 pts each; 10 pts total)

Physiological ecology Niche

Null hypothesis

The Kill Curve

Statistical significance

Mimicry

Ecology

Fill in the missing word or phrase for FOUR of the following. (3 pts each; 12 pts total)

  1. Organisms displaying similar adaptations between similar environments is referred to as ______________________________________? (submitted by fellow student)
  2. The potential "multidimensional hyperspace" of resource use is referred to as an organism’s _________________________; where it actually lives is called its ________________________________.
  3. It was originally believed that the deer population on the Kaibab Plateau in Arizona grew rapidly following the elimination of ___________________________ but the population probably increased due to the elimination of _______________________________.
  4. If data are skewed you should use the _____________________ as an estimate of central tendency.
  5. The two most important factors influencing soil development and type are ___________________________ and _____________________________. (submitted by fellow student)

Design an experiment (10 pts)

The level of CO2 in the atmosphere has been increasing for several decades and is expected to double by the year 2050. Plants need CO2 to grow. Design an experiment to test the effect of increased CO2 on the height of goldenrod. Do not provide an introduction, results, justification, or poetry. Assume that you have the necessary equipment and time for this experiment. Feel free to provide a diagram of the experimental design if this reduces how much you have to write. (Continue on the back of this sheet if you must)