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Earth System Science
1. Which of the following elements is not a major component of living systems?
a. Carbon
b. Nitrogen
c. Oxygen
d. Potassium
Answer: d
2. Excluding human-induced effects, most elements enter freshwater systems from
a. rainfall.
b. oceans (through tidal movements).
c. actions of animals.
d. weathering of rocks (via groundwater).
e. plants and plant parts decaying in streams, lakes, and rivers.
Answer: d
3. Most of Earth’s nitrogen is in
a. the atmosphere.
b. the oceans.
c. freshwater systems.
d. soil.
e. organisms.
Answer: a
4. The gas that is removed from the atmosphere by plants and algae is
a. N2.
b. O2.
c. CO2.
d. methane.
e. water vapor.
Answer: c
5. Most of the world’s carbon is found
a. as CO2 in the atmosphere.
b. in living organisms.
c. as bicarbonate and carbonate ions dissolved in the oceans.
d. as carbonate minerals in sedimentary rock.
e. in the decaying remains of dead organisms.
Answer: d
6. Photosynthesis and respiration are central to which cycle?
a. Nitrogen cycle
b. Carbon cycle
c. Phosphorus cycle
d. Sulfur cycle
e. Hydrological cycle
Answer: b
7. Why is nitrogen often in short supply in terrestrial ecosystems?
a. There is very little free nitrogen in the air.
b. Atmospheric nitrogen is primarily in the stratosphere and does not come into contact
with terrestrial ecosystems.
c. Atmospheric nitrogen cannot be used by most organisms. It needs to be converted to
useful forms by bacteria and cyanobacteria.
d. Nitrogen solubility in water is very low and therefore atmospheric nitrogen enters cells
very slowly.
e. Atmospheric nitrogen varies widely from location to location. As a result local
shortages occur frequently.
Answer: c
8. The phosphorus cycle differs from the carbon cycle in that
a. phosphorus does not enter living organisms, whereas carbon does.
b. the phosphorus cycle does not include a gaseous phase, whereas the carbon cycle does.
c. the phosphorus cycle includes a solid phase, whereas the carbon cycle does not.
d. the primary reservoir of the phosphorus cycle is the atmosphere, whereas the primary
reservoir for the carbon cycle is rock.
e. phosphorus passes through living organisms many times, whereas carbon flows
through living organisms only once.
Answer: b
9. Acid precipitation
a. occurs naturally when clouds are formed by evaporation over land.
b. occurs naturally when clouds are formed by evaporation over oceans.
c. occurs as a result of the burning of fossil fuels that contain sulfur and nitrogen
compounds.
d. occurs because of carbon monoxide emissions by automobiles.
e. occurs when large forest tracts are logged or otherwise deforested.
Answer: c
10. The two main human-induced causes of increased CO2 levels are
a. the burning of fossil fuels and the burning of forests.
b. the burning of fossil fuels and the raising of cattle.
c. modern agricultural fertilizers and the raising of cattle.
d. pollution-induced mortality of oceanic algae and the burning of forests.
e. modern agricultural fertilizers and pollution-induced mortality of oceanic algae.
Answer: a
11. In the movement of energy and nutrients through ecosystems, energy _______, and
nutrients _______.
a. flows; flow
b. flows; cycle
c. cycles; cycle
d. cycles; flow
e. flows; either cycle or flow
Answer: b
12. Which of the following does not influence a terrestrial ecosystem?
a. Solar energy fluxes
b. Earlier successional stages
c. Local species richness
d. Global atmospheric circulation
e. Eutrophication
Answer: e
13. Which of the following statements regarding the hydrological cycle is false?
a. Most input to the oceans occurs via runoff from rivers.
b. The amount of water that evaporates from the surface of the oceans is greater than the
amount that falls as rain over them.
c. The amount of water that evaporates from the surface of the land is less than the
amount that falls as rain over it.
d. Water found in sedimentary rock is constantly exchanged with the ocean.
e. The energy driving the hydrological cycle is heat from the sun.
Answer: d
14. Which of the following biogeochemical cycles is characterized by a major reservoir
that is gaseous, and a major gas phase that can be utilized only by a small group of
bacteria and cyanobacteria?
a. Carbon cycle
b. Nitrogen cycle
c. Phosphorus cycle
d. Sulfur cycle
e. Oxygen cycle
Answer: b
15. In which of the following biogeochemical cycles is the gaseous phase a major
greenhouse gas?
a. Carbon cycle
b. Nitrogen cycle
c. Phosphorus cycle
d. Sulfur cycle
e. More than one cycle
Answer: a
16. Which of the following biogeochemical cycles lacks a gaseous phase?
a. Carbon cycle
b. Nitrogen cycle
c. Phosphorus cycle
d. Sulfur cycle
e. Oxygen cycle
Answer: c
17. Which of the following biogeochemical cycles has a gaseous phase made up of
emissions from volcanoes and fumaroles?
a. Carbon cycle
b. Nitrogen cycle
c. Phosphorus cycle
d. Sulfur cycle
e. Oxygen cycle
Answer: d
18. The land compartment of Earth is connected to the atmospheric compartment through
a. runoff from rivers.
b. organisms that process chemical elements.
c. zones of upwelling.
d. chemical elements that enter groundwater.
e. None of the above
Answer: b
19. In the human-induced condition called eutrophication, the main biogeochemical cycle
that is altered is the _______ cycle; the effect is the creation of _______ conditions and a
decrease in species diversity.
a. hydrological; aerobic
b. phosphorus; anaerobic
c. hydrological; aerobic
d. phosphorus; aerobic
e. nitrogen; anaerobic
Answer: b
20. In the human-induced condition called acid precipitation, the main biogeochemical
cycles that are altered are the _______ cycles.
a. phosphorus and nitrogen
b. phosphorus and nitrogen
c. nitrogen and sulfur
d. nitrogen and sulfur
e. phosphorus and sulfur
Answer: c
21. Which of the following occurrences is not considered to be a likely consequence of
global warming?
a. Melting of the polar ice caps
b. Flooding and increased precipitation in coastal areas
c. Increased ozone depletion
d. Average worldwide temperature increase of 3–58°
Answer: c
22. Primary production is higher in zones of upwelling because
a. water in these zones conducts nutrients poorly.
b. nutrient levels are lower in these zones.
c. a thermocline exists in these zones.
d. water is more dense at 4ºC.
e. the water in these areas has a greater concentration of nutrients.
Answer: e
23. Which of the following gases is not part of Earth’s atmosphere?
a. O2
b. N2
c. Chlorine
d. Water vapor
e. CO2
Answer: c
24. The process that redistributes nutrients in freshwater lakes is called
a. upwelling.
b. eutrophication.
c. the hydrological cycle.
d. turnover.
e. denitrification.
Answer: d
25. The sulfur cycle influences the global climate because
a. sulfur compounds are important greenhouse gases.
b. sulfur compounds help transfer carbon from the atmosphere to the oceans.
c. sulfur compounds in the atmosphere are particles around which water condenses to
form clouds.
d. sulfur compounds contribute to acid precipitation.
e. The sulfur cycle does not influence the global climate.
Answer D.