Justify the following statement in terms | Class 12 Biology Chapter Ecosystem, Ecosystem NCERT Solutions

Productivity refers to the rate of formation of biomass in an ecosystem and is usually expressed in the unit of mass per unit area per unit time. Productivity is different from biomass as productivity is the rate at which organic matter is created by the producers whereas biomass is the amount of organic matter present at any given time which is generally expressed in wet and dry terms. In the P/R ratio P is the productivity and R is the respiration. In this the total rate of photosynthesis, including the biomass that used in respiration process during the measurement is known as Gross Primary Productivity (GPP). And, the rate of storage of biomass in the plants which exceeds the respiratory use by them is known as Net primary Productivity (NPP) which is the available biomass for the consumption to Heterotrophs. This can be described as following equation:

NPP (Net primary Productivity) = GPP (Gross Primary Productivity) - R (Respiration by autotrophs)

1. Nature tends to increase the gross primary productivity so that it can use much of their sunlight or solar radiations and convert it in the food.
2. Men tends to increase the net primary productivity so that enough food will be provided to the growing population of the human beings.