Which of the following organisms is correctly paired with a trophic level?
a. cyanobacterium—secondary consumer
b. grasshopper—primary consumer
c. zooplankton—primary producer
d. grass—decomposer
Which of the following organisms is correctly paired with a trophic level?
a. cyanobacterium—secondary consumer
b. grasshopper—primary consumer
c. zooplankton—primary producer
d. grass—decomposer
Which of these ecosystems has the lowest net primary production per square meter? a. a salt marsh b. an open ocean c. a coral reef d. a tropical rain forest
Nitrifying bacteria participate in the nitrogen cycle mainly by a. converting nitrogen gas to ammonia. b. releasing ammonium from organic compounds, thus returning it to the soil. c. converting ammonium to nitrate, which plants absorb. d. incorporating nitrogen into amino acids and organic compounds.
Which of the following has the greatest effect on the rate of chemical cycling in an ecosystem? a. the rate of decomposition in the ecosystem b. the production efficiency of the ecosystem's consumers c. the trophic efficiency of the ecosystem d. the location of the nutrient reservoirs in the ecosystem
Which of the following was a result of the Hubbard Brook watershed deforestation experiment? (A) Most minerals were not recycled within the intact forest ecosystem. (B) Calcium levels remained high in the soil of deforested areas. (C) Deforestation decreased water runoff. (D) The nitrate concentration in waters draining the deforested area became dangerously high.