Study Questions for Ecosystems

FOR FALL 2006: CONCENTRATE ONLY ON QUESTIONS 7 - 9 (8 & 9 were added today, 12/6/06)

1.       Distinguish an ecosystem from a biological community.  How large is an ecosystem?

2.       What is the general difference in the nature of energy flow in ecosystems versus the flow of mineral nutrients (e.g., Nitrogen, Phosphorus, etc.)?

3.       Which is more likely to occur in nature: a food web or a food chain?  Why?

4.       Discuss the problems associated with pyramids of numbers and biomass when displaying trophic relationships in an ecosystem.  What is a fundamental problem with a pyramid of energy flux?

5.       You are asked by the Department of Ecology to estimate the primary productivity of forests in western Washington in 100 years given that climate change will occur.  What kind of information would be useful and why?

6.       If corn fields in Iowa produce 12,500 J per square meter of chemical energy in primary production, how much energy does this translate into for the cows that eat that corn and the humans (you!?) that eat the hamburgers from those cows? 

7.       Draw the nitrogen cycle and identify the major pools and fluxes. On the exam I will expect you to know the major pools and fluxes of the nitrogen cycle and the things that affect those fluxes.  Identify where humans have significant impacts on this biogeochemical cycle.

8.   In what steps of the nitrogen cycle are bacteria key players?

9.   Imagine a forest where mushroom hunters have disrupted the population and function of fungi, a major class of decomposers. Describe what might happen to nitrogen cycling (examine the different steps: pools and fluxes; how would they change?) and how this might impact overall ecosystem primary productivity.