EE Biology 3270, Ecosystem Ecology NAME_____________________________________
Point values of questions are shown. Be TERSE (be brief) and please, PLEASE, print clearly!
1. The net radiation budget at the surface of the earth is:
S(1-a) = L + LE + H + G + Ps (see board for definitions)
Where Ps is the energy captured by photosynthesis. This amount is often so small as to be an “error term” in measurements. Why, then, do plants matter in this budget? For the energy terms a, L, LE, H, and G explain how vegetation can alter these values. (2 pts each)
a_________________________________________________________
L__________________________________________________________
LE_________________________________________________________
H__________________________________________________________
G__________________________________________________________
2. You testify before congress about how climate change is affecting ecosystems.
A congressman asks you, “What is an ecosystem?”
(You are allowed to use scientific jargon. He/She won’t understand, but that’s ok here.) (4 pts)
3. Write a formula for rock weathering that is “ecologist-friendly” (i.e., we understand it) (2 pts)
4. What is the common source of acid used to drive chemical reactions in soil? (2 pts)
5. We looked at soil profiles in class. We noted that, for the same climate, the same topography,
the same type of parent material, and the same age of the parent material, that soil profiles could differ markedly in their appearance (and chemical composition). What can cause that? (2 pts)
6. Examine the following graph. NPP = Net plant production or aboveground plant production.
The two lines represent soils composed of different textures.
For the graph below, what soil texture is represented by the line marked “a” ?: (2 pts)
a) organic matter b) sand c) silt d) clay
7. Write a two sentence description explaining what this graph is trying to say. (4 pts)
8. The pattern portrayed on the graph makes sense if: (2 pts each for multi-choice from here)
a) Differences are due to soil nutrients
b) the amount of 2:1 clays in the soil must differ.
c) different reflectivity of soil types causes this difference
d) sunlight removes water in the top few centimeters of both soil types
9. The best science explanation for finding groundwater beneath arid soils is:
a) climate change d) macropore movement of water
b) intelligent design e) a deep soil profile consisting of clays and sands
c) failure of plant roots to keep water at shallower depths
10. A soil is at permanent wilting and holds 0.3 ml of water per CC of soil.
This soil is capable of holding 0.5 ml of water at field capacity and 0.6 ml of water at saturation.
a) what’s the pore space in this soil?
1. 0.3 CC
2. 0.5 CC
3. 0.6 CC
4. can’t determine from data given
b) if a 2 cm (2 CC) rain event falls, we should find the soil to be wetted to:
1. 2 cm
2. 10 cm
3. 15 cm
4. 18 cm
5. if the soil has only micropores you can’t be sure.
11. In a humid environment, a good estimate of the amount of energy transported from
The surface of a forested ecosystem in the form of water vapor would be
a) 14%
b) 46%
c) 64%
d) 90%
12. (2 pt) You knew the above answer because:
a) sensible heat averages 14% of incoming solar energy, assuming water is present
b) latent heat averages 46% of solar energy, assuming water is present.
c) Longwave radiation averages 64% of incoming solar energy, assuming water is present.
d) I always get 90% on these exams.
13. The best index of soil fertility (ability to provide nutrients) is
a) amount of sand
b) amount of silt
c) amount of clay
d) amount of pore space
14. You should expect soil fertility to be highest in soils with lots of
a) 2:1 clays like those found on the prairie
b) 1:1 clays like those found in the eastern deciduous forest
c) iron and aluminum oxides like those found in the tropics.
d) High amounts of silica
15. The best measurement of plant available water per unit of soil volume is:
a) saturation minus field capacity.
b) Saturation minus permanent wilting
c) Field capacity minus permanent wilting
d) Pore space – field capacity
e) Pore space – permanent wilting.
Info: soil texture is composed of sand, silt and clay. Soils are a gradient of these materials, with loam soils defined as a mixture of the three.
16.__________ soils will usually hold the most nutrients, but _______ soils usually are best at holding plant-available water per unit of soil volume. The blanks should be (pick one letter):
a) sand, clay
b) clay, sand
c) clay, loam
d) loam, clay
e) clay, loam
f) sand, loam
g) loam, sand
17.Eugene Odum, the father of modern ecosystem ecology, used to talk about “emergent” properties of ecosystems. These were characteristics that can’t easily be explained by studying “parts” alone. Give an example of an emergent property of an ecosystem and a one sentence explanation for your choice.
(NOTE: do not use “water” as your example. (2 pts).
18.Speaking of water, name two traits that make water a “real player” in terms of energy use in ecosystems (what characteristics or properties make it special?) (2 pts)
19.Why is it wetter, on average (more rainfall) in the Southern Hemisphere than in the Northern Hemisphere? ( 2 pts)
20.More longwave energy leaves at the poles than comes in from solar radiation. How is that possible? (2 pts)
21. Human changes of ecosystems is affecting global climate in many ways. List an example of how (2 pts each)
a) Land use change can REDUCE the absolute amount of energy available at the surface
b) A modification involving water that will result in local cooling.
c) A modification to vegetation that will increase surface water amounts (this was something suggested in Colorado towards the end of the 2002 drought!)