Class 12 NEET Biology Ecosystem Questions

(c) : The source of energy in all ecosystem is solar energy. About 50% of the solar energy incident over earth is present in PAR (Photosynthetically active radiation). About 1−5% of incident solar radiation or 2−10% of PAR is captured by the photosynthetic organisms in the synthesis of organic matter (gross primary productivity). Roughly 20% of it is consumed in respiration so that net capture of energy (net primary productivity) is 0.8−4% of incident radiation or 1.6−8% of PAR.