Environmental Science 362-302 Name_______________________
EXAMINATION #2
[Note: You are given several choices for questions to answer. If you answer more than
the required number, I will only grade as many as you were supposed to answer -- any
additional answers will not be graded.]
Part I: Identification. Briefly define 5 of 6 (4 points each for a total of 20 points)
1.1 Zooxanthellae
1.2 S-Strategist
1.3 Michaelis-Maenten Curve
1.4 Appearancy Hypothesis
1.5 Muellerian Mimic
1.6 Convection
Part II. Short Answers. Answer 8 of 10 (6 points each for a total of 48 points). Be
sure to label axes for any graphs, and parts of any diagram.
2.1 Diagram the distribution of carboxylase enzymes in the leaves of (a) C3, (b) C4, and
(c) CAM plants
2.2 Diagram the conditions under which competitive exclusion will occur in LotkaVolterra
competition models.
2.3 Illustrate hypothetical population pyramid diagrams for (a) the southern U.S. two
decades after the Civil War, (b) the population of Ft. Lauderdale during March, and (c) a
population which has reached replacement reproduction but which is still growing.
2.4 What environmental conditions will select for semelparity? Why?
2.5 List three strategies which plants have evolved to encourage seed dispersal via
animal vectors. In each case, tell me what the animal is getting out of this arrangement.
2.6 List three ways in which plants living in alpine tundra can achieve relative
temperature stability. Tell me which components of the basic energy flux model each is
modifying.
2.7 List 6 life history factors that distinguish r and K strategists, and provide how they
differ between these two groups.
2.8 Show me a ZNGI for a hypothetical species (a) before and (b) after an allelopathic
competitor arrives on the scene.
2.9 List and describe (through words or pictures) the three main assumptions which limit
the predictive ability of classical Lotka-Volterra predator-prey models.
2.10 Lots and lots of fingerling bass are dumped into an (a) nutrient rich and (b) nutrient
poor lake. Diagram the relationship between average individual mass and density for
these two lakes over time, assuming no more individuals are stocked into the lake.
Part III. Problems.
3.1 You observe a cohort of 550 fish for several years. You find that average number of
individuals alive during the first year 333, during the second is 82, during the third is 36,
during the fourth is 14, and during the fifth is 2. Determine lx, qx, and ex for this
population. (9 pts)
3.2 You also studied the reproduction within this population. You observed that the
average number of female offspring produced per female during the first year was 0.34,
in the second year 1.42, in the third year 1.88, in the fourth year 2.02, and 2.33 for all
females living past their fourth year. If you assume that there are no differences in the
survivorship between males and females, tell me the average generation time and
doubling time for this population. (8 points)
Part IV. Short Essay. Answer 1 of 2 (15 points).
4.1 Two very rare species are suddenly forced to live together due to habitat destruction.
Unfortunately, one of the species is able to cause competitive exclusion of the other.
Suggest (using words and drawings) a general plan to allow coexistence of these two
species in (a) Lotka-Volterra and (b) Resource Ratio models. Then, make specific, realworld
recommendations about how you would try to accomplish these goals.
4.2 Of the many factors of global change facing the planet right now, perhaps one of the
more profound is the enrichment of the atmosphere in CO2, which may cause substantial
global warming. Any such change in climate will cause the ranges of species to shift.
Some species may have their entire range shifted, as they will be completely unable to
survive in the areas they now occupy. Design (and justify) a research plan which will
help identify such species.