52. Ecosystems

What are the major factors that control primary production in terrestrial ecosystems?

What frequently causes eutrophication in lakes?

What is the amount of chemical energy in a consumer's food that is converted to its own new biomass over a period of time called?

In the transition from each trophic level of the food chain to the next trophic level, there is about a __________.

Which of the following best describes the base of a pyramid of net production?

In general, the biomass in an ecosystem will be greatest at the trophic level comprising __________.

What is the main abiotic reservoir for elements, such as calcium and phosphorus, involved in local biogeochemical cycles?

In ecosystems, organisms at the highest trophic levels usually contain less collective biomass than the organisms at lower trophic levels because __________.

Which of the following statements is correct?

The global water cycle supports a net flow of atmospheric water vapor __________.

Local conditions such as heavy rainfall or the removal of plants may limit the amount of nitrogen, phosphorus, or calcium available to a particular ecosystem, but the amount of carbon available to the system is seldom a problem. Why?

By which process is carbon dioxide released from plants back to the atmosphere?

Which of the following is a key part of the carbon cycle?

Bacteria are especially important in making __________ available to plants.

The direct product of nitrogen fixation is __________.