NEET2026BiologyChapterActual
In a terrestrial ecosystem, the Gross Primary Productivity (GPP) of the producers is 20,000 kcal m ⁻² yr ⁻¹ . If the producers utilize 20 % of this energy for their own respiration, what amount of energy will be available to the secondary carnivores in a four-trophic-level food chain?
Options
- A160 kcal m ⁻² yr ⁻¹
- B1,600 kcal m ⁻² yr ⁻¹
- C20 kcal m ⁻² yr ⁻¹
- D2,000 kcal m ⁻² yr ⁻¹
Correct answer
A. 160 kcal m ⁻² yr ⁻¹
Step-by-step solution
The Gross Primary Productivity (GPP) of producers is 20,000 kcal m ⁻² yr ⁻¹ . The energy utilized for respiration (R) by producers is 20 % of GPP. R = 20 100 20,000 = 4,000 kcal m ⁻² yr ⁻¹ The Net Primary Productivity (NPP) is the energy available to the primary consumers (herbivores). NPP = GPP - R NPP = 20,000 - 4,000 = 16,000 kcal m ⁻² yr ⁻¹ According to Lindeman's 10 % law of energy transfer, only 10 % of the energy is passed on to the next trophic level. Energy available to primary consumers (herbivores) = 16,