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Biology Assessment: Ecology and Environment

QUESTION 1
Which region contains the largest amount of the global nitrogen pool?

• Fossil fuels
• Aboveground terrestrial systems
• Ocean
• Atmosphere

QUESTION 2
In general, litter with a C/N ratio greater than 30 leads to immobilization, litter with a
C/N ratio less than 20 leads to mineralization, and litter with a C/N ratio of 20-30 leads
to a balance of immobilization and mineralization resulting in no net N production. If
garlic mustard leaf litter collected on the forest floor had 43.2 percent C and 1.16
percent N, this tissue would lead to __________. (hint: divide C by N)

• immobilization
• mineralization
• a balance of immobilization and mineralization
• preferential consumption

QUESTION 3
Carbon dioxide concentrations fluctuate in predictable seasonal patterns on the surface
of the planet largely as a result of _____________.

• the influence of vegetation patterns in tropical systems
• weathering of rock surfaces following seasonal rain events
• vegetation growth and flux patterns in aquatic systems
• large-scale patterns of terrestrial plant uptake and dormancy

QUESTION 4
Which of the following is the slowest to decompose?

• Proteins
• Sugars
• Lignins
• Cellulose

QUESTION 5
Which of the following nutrients is most closely linked to the energy cycle in
ecosystems?

• Carbon
• Nitrogen
• Lead
• Sulfur

QUESTION 6
Match the answer to the question.
________ is the process by which plants absorb a portion of their nutrients from senescing tissues to be stored and used for the
production of new tissues. The breakdown of chemical bonds that were formed during the construction of plant and animal tissues is called ________. The release of organically bound nutrients into an inorganic form is called ________. The introduction of high levels of nutrients into a body of water is called ________. Precipitation brings appreciable quantities of nutrients into ecosystems that are collectively called ________. Large quantities of nutrients are bound tightly in ________ structure; they are not readily available until released by the activities of decomposers. Some nutrients are ________ from the soil and carried out of ecosystems by underground water ecosystems by underground water flow to streams. The element ________ is a basic constituent of all organic compounds and is involved in the fixation of energy by photosynthesis. The difference between the rate of carbon uptake in photosynthesis and the rate of carbon loss due to autotrophic and heterotrophic respiration is the net ________ productivity. Nitrogen is generally available to plants in only two forms: ammonium and ________. Biological nitrogen fixation is accomplished by symbiotic ________ living in mutualistic association with plants. Nitrogen can be returned to the atmosphere when certain bacteria convert it from nitrate into nitrogen gas, which is a process called ________. Microbial decomposition of organic matter results in NH4+ production through a process called ________. Nearly all of the phosphorus in terrestrial ecosystems comes from the ________ of calcium phosphate minerals. ___________ develop as a result of incomplete decomposition of organic matter in swamps and marshes. The process of ____________ produces a form of nitrogen that is easily lost from soil through leaching. ____________ is when too much nitrogen enters an ecosystem and causes forest decline. _________ primary productivity is the total rate of photosynthesis or energy assimilated by plants. Plants assimilate energy through the process of _______________.

1. decomposition
2. carbon
3. ammonification
4. fossil fuels
5. organic
6. denitrification
7. nitrification
8. leached
9. nitrate
10. net
11. photosynthesis
12. weathering
13. eutrophication
14. mineralization
15. respiration
16. gross
17. wetfall
18. ecosystem