Exam 57: Ecosystems

A desert environment has a very low NPP.What does this suggest about the number of trophic levels in its food webs?

The flesh of a dead animal is broken down by many types of decomposers.During the last part of this process, the flesh is turned into small soluble nutrients, such as ions of nitrogen, phosphorus, and sulfur, which can be used by plants in primary production.This final part of the decomposition process is known as

Refer to the figure. Using the graphic as a basis, explain the loss of energy at each trophic level in the grassland ecosystem.What causes the loss, and what happens to the energy?

According to FACE experiments performed in different ecosystems, trees are better able to increase their NPP in response to increasing CO₂ than are grasses, crops, and other herbaceous plants.This suggests that, to counteract the effects of increasing atmospheric CO₂, humans would obtain the most noticeable effects by

In forest ecosystems, bears often eat a varied diet.Two food chains in which they may participate are: If bears eat only rodents, they are secondary consumers.If they eat both rodents and berries, they are omnivores.How will ecosystem NPP change if bears act as omnivores rather than secondary consumers?

An important way sulfur is moved from its global pools into the active sulfur cycle is by

Pollution of lakes and streams by sewage or fertilizer runoff results in addition of excess nutrients, which in turn leads to the process of _______.

Refer to the figure. What ecosystem do these diagrams represent, and why is the biomass pyramid inverted (with a smaller biomass of primary producers than of primary consumers)?

Refer to the figure. A major difference between carbon cycling on land and at sea is that on land

A reduction in dimethyl sulfide production in the oceans would likely have what effect on global climate?

As CO₂ concentrations in the atmosphere increase, how might the increase be expected to influence land-based NPP rates?

Both desert and tundra have very low NPP values.What factor or factors determine NPP values in these two biomes?

Refer to the figure. How would the NPP of a three-level food web (left) compare with that of a two-level web (right) and why?

A major characteristic of the phosphorus cycle is that it

The Ogallala Aquifer runs from South Dakota to Texas in the plains of the Midwest.It has been depleted rapidly in recent years, as farmers have withdrawn water for irrigation, and will be 69 percent depleted by 2060.How does depletion of this and other aquifers affect the hydrologic cycle?

Refer to the figure. The algal bed and coral reef ecosystem type and the swamp and stream ecosystem type each have an average net primary productivity close to that of tropical rainforests.However, each makes up a much smaller percentage of Earth's net primary production than do rainforests.What factor accounts for this difference?

Studies in agricultural science show that the net efficiency of energy utilization differs in beef cattle and dairy cattle, with beef cattle being more efficient.This is because beef cattle store more body fat than dairy cattle, although the two store the same amount of protein.This information suggests that the researchers are measuring which type of efficiency?

A scientist studying the sulfur cycle is particularly interested in the movement of sulfur through organisms in terrestrial ecosystems.To see most of the interactions of sulfur with these organisms, she should concentrate her measurements on which environmental pool of sulfur?

Compared with ocean productivity, land productivity

Which description does not fit the definition of an ecosystem study?