Q11 of 42 Page 1

Write the relationship between productivity, gross primary productivity, net primary productivity and secondary productivity.

• Productivity-The rate of biomass production is called productivity.


• Gross primary productivity (GPP) of an ecosystem is the rate of production of organic matter during photosynthesis.


• Net primary productivity (NPP)-A considerable amount of GPP is utilized by plants in respiration. Therefore the net primary productivity is the gross primary productivity minus respiration losses (R).


GPP – R = NPP


• For the consumption of heterotrophs (herbivores and decomposers), the available biomass is the net primary productivity.


• Secondary productivity- the rate of formation of new organic matter by consumers.


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