(edited 3/30/14)
Study questions for aquatic ecology sections (added at end of N & P talks)
1) Streams are classified by their distance from headwaters.
Explain how the following limiting factors change as one goes from headwaters
to largest rivers:
a) light limitation; b) nutrient limitation ; c) NPP (plant productivity)
2. If headwater streams have extremely low in-stream NPP values, why can they be full
of insects? (often 10 times the biomass found on land)
3. While coastal areas of the ocean are often thought to be nitrogen limited, the main
part of the ocean is phosphorus limited. Why is that?
4. How do large, deep lakes sometimes function like the open ocean in terms of NPP?
5. What is the main difference between deep lakes and the open ocean in terms of
water density and temperature? Why does this make lakes more productive during
portions of the year?
6. How do latitudinal patterns of oceanic NPP differ from that observed on land?
What causes the oceanic patterns? (hint: NOT AET....that's a land pattern).
9. Animal examples of ‘nutrient pumps’ (move nutrients uphill) are few and usually
connected to aquatic systems. Name a few animals that function as nutrient pumps.
(hint: see http://www.bouldercounty.org/os/openspace/pages/ospreycamera.aspx ).
10. About what percentage of NPP is consumed by herbivores in the open ocean (and
selected other aquatic ecosystems)? How does this compare to terrestrial ecosystems?
11, Why doesn’t the ocean experience ‘turn-over’ like our temperate lakes? Where do
we find nutrient-rich oceanic surface waters?
Study questions for first two lectures on trophic dynamics (chpt 10)
1. In the relationship: productivity = ingestion minus respiration minus egestion
(P=I-R-E), and where production = Assimilation minus Respiration (P=A-R),
How does a) food 'quality' affect the equations?
b) the energy used to capture food affect the equations?
2. An elk herd that has no predators is not increasing or decreasing in energy content
on an annual basis (i.e., average herd size and average animal size is constant).
Where's the production in this herbivore component?
3. Can energy cycle? Can a hunk of energy travel several times through a food web?
4. Trophic level analyses (biomass or energy pyramids) may be interesting descriptions
and interesting ways to compare ecosystems. However, what's the "fairy tale" in this
picture? Why do most ecologists not put much emphasis in trophic level analyses?
6. Write a commercial for "The diet to end all diets" i.e., a guaranteed weight
loss program. What’s the basic principal behind the diet (think P=I-E-R or P = A-R)?
7.Cattle/hog/chicken growers have been heard to boast of "20% efficiency" in developing
their products. Why is this fact not only extremely unlikely, but probably a gross
overestimate of the efficiency?
8) what ecosystem has the highest percentage of NPP consumed, on average, by
herbivores.
7) Name a chemical of very large molecular weight that functions to dilute resource
quality and therefore discourage herbivory?
8) Name some chemicals that are small molecular weight that function as herbivore
poisons or feeding deterrents.
9) Do anti-herbivore chemical defenses contain materials other than carbon, hydrogen,
and oxygen? If so, what are these called and where are they found?
10) Some plants are only fed upon by 'specialist herbivores'. What's special about these
animals?
11) Explain how the relative growth rate (RGR) of a plant can a) increase, b) remain
the same or c) decrease when plants are grazed by (say) ungulates.
12. What factors may cause the relative growth rate of foliage to increase after other
foliage is removed by herbivores?
****we may not get to some of these questions on 4/7. If not covered in class, they’re
not on the exam.