Question

Which of the following statements about productivity is true?

• A. Primary productivity of all ecosystems is a constant
• B. Annual net primary productivity of the whole of the biosphere is 17 billion tons (dry weight) of organic matter
• C. Net primary productivity is the amount of biomass available for consumption by carnivores
• D. Secondary productivity is defined as the rate of formation of new organic matter by decomposers
• E. Primary productivity depends upon the plant species inhabiting a particular area

Answer 1

The correct option is E Primary productivity depends upon the plant species inhabiting a particular area

a) Primary productivity of all ecosystems varies depending upon the number of producers in an ecosystem.

b) Annual net primary productivity of the whole of the biosphere is 170 billion tons (dry weight) of organic matter.

c) Gross primary productivity is the rate of photosynthesis. Net primary productivity is the rate of storage of organic matter except which is utilized for the respiration by plants. It is the total biomass available for consumers.

d) The rate of formation of new organic matter by producer is called as secondary productivity. Consumer level includes herbivores, carnivores and decomposers. In other words, it is the rate of formation of new organic matter by consumers.

e) In a food chain, energy stored at the producer level is called as primary productivity. Primary productivity depends upon the plant species inhabiting a particular area.

Thus, the correct answer is 'Primary productivity depends upon the plant species inhabiting a particular area.'