Environmental Science 362-302 Name_______________________
EXAMINATION #3
[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 Histisol
1.2 Return Interval
1.3 Photo-inhibition zone
1.4 Thinning stage
1.5 Alpha diversity
1.6 Nitrate Reductase
Part II. Short Answers. Answer 7 of 9 (6 points each for a total of 42 points).
2.1 What are the major mechanisms that have been proposed to account for successional
change in community composition and how do they differ?
2.2 What are the major similarities and differences in the symbiotic strategies land plants
have developed to aid in the uptake of soil N and P?
2.3 List and define each of the Raunkier life form guilds for plants, and give an example
of each.
2.4 Describe two equilibrium mechanisms that can account for species richness patterns
over ecological time scales.
2.5 Describe three non-equilibrium mechanisms that can account for species richness
patterns over ecological time scales.
2.6 Why do gardeners often add chopped Sphagnum peat to improve plant growth in
sandy soils, even though this peat has very low nutrient levels?
2.7 Diagram the major ways that communities have been thought to be organized by
showing how their composition varies along a given environmental gradient.
2.8 Show the chemical equations that are vital in describing the global atmospheric
Carbon cycle.
2.9 Why are terrestrial ecosystems most often limited by Nitrogen, while aquatic systems
are most often limited by Phosphorus?
Part III. Problem Sets.
3.1 A series of 1x1 meter sample quadrats are placed in a Sphagnum bog in northern
Langlade County. A few of these are sealed off, and the atmospheric chemistry inside of
them is measured. The yearly levels of energy flux from sunlight on this bog is 1.2
million kcal per square meter. By monitoring the change in CO2 levels, it is estimated
that during an average growing season 9500 kcal of energy in the form of C6H12O6 is
accumulated by the vegetation in this quadrat. By measuring fluctuations in nighttime
CO2 levels, it is estimated that, on average, 8700 kcal of energy per year is released
through respiration. The rare Freija Fritillary butterfly lives on the vegetation found in
this bog. On average, this species consumes 2000 kcal of vegetation per year per quadrat.
During this time, it releases 700 kcal per year in the form of feces and 200 kcal per year
in the form of urine. At the end of each year, 60 kcal of energy has been stored as
butterfly biomass, and 15 kcal has been provided to butterfly reproduction.
From this data calculate:
A. GPP efficiency (3 pts)
B. Production efficiency of the Freija Fritillary (3 pts)
C. Consumption efficiency of the Freija Fritillary (2 pts)
D. Lindeman's efficiency between the vegetation and the butterfly (hint: plant
assimilation is
equal to what?) (3 pts)
3.2 The vegetation of these quadrats is also identified. A total of five species are
recorded, and their abundances measured:
Leatherleaf 20
Cranberry 17
Pitcherplant 2
Cottonsedge 22
Bog Rosemary 7
A. Do you think the Probability Theory or Information Theory indices will have the
highest heterogeneity? Defend your answer! (4 pts)
B. Now, test your hypothesis. Calculate heterogeneity for this sample using both
indices. Was your prediction correct? (8 pts)
Part IV. Longer essay. Answer 1 of 2 (15 points)
4.1 Even though the same genera of forest trees are found in eastern North America and
eastern Asia, the richness of tree species in Asian forests is at least five times greater.
Propose a series of hypotheses that could help explain this pattern, and defend each.
4.2 Given the information you now know about global biogeochemical cycles, discuss
those which you feel most significantly impact Brown County terrestrial systems. Do the
same for Brown County aquatic systems. Defend your answers, and suggest ways in
which these impacts can be mitigated.