Ques. 1AIPMT 2004
Which of the following is expected to have the highest value (g/m2/yr) in a grassland ecosystem ?
- Net production (NP)
- Secondary production
- Tertiary production
- Gross production (GP)
Answer
(4) Gross production (GP)
Solution
As per NCERT, gross primary productivity (GPP) is the rate of production of biomass during photosynthesis.
NPP = GPP - R (R = respiration losses), so NP is less than GP.
∵ Only about 10% of energy passes to each next trophic level, secondary and tertiary production are still smaller.
∴ GP > NP > secondary > tertiary production
Answer: (4)