NEETBotanyEcosystem
What is the annual net primary productivity of the whole biosphere?
Options
- A55 billion tons (dry weight)
- B170 billion tons (dry weight)
- C70 billion tons (dry weight)
- DNone of the above
Correct answer
B. 170 billion tons (dry weight)
Step-by-step solution
A constant input of solar energy is the basic requirement for any ecosystem to function and sustain. Primary production is defined as the amount of biomass or organic matter produced per unit area over a time period by plants during photosynthesis. It is expressed in terms of weight (g m–2) or energy (kcal m–2). The rate of biomass production is called productivity. It is expressed in terms of gm–2 yr –1 or (kcal m–2) yr–1 to compare the productivity of different ecosystems. It can be divided into gross primary pro