Energy flow through trophic levelsपोषण स्तरों से ऊर्जा प्रवाह

NCERT Fig 12.3 · Class 12 Biology · Chapter 12 · interactive diagram

Parts and their functions

• Sun (सूर्य) — The only source of energy for all ecosystems on Earth, except the deep-sea hydro-thermal ecosystem.
• PAR (photosynthetically active radiation) (प्रकाश संश्लेषणी सक्रिय विकिरण (PAR)) — Less than 50% of the incident solar radiation is PAR — the part plants can use.
• Producers (उत्पादक) — Plants capture only 2–10% of the PAR — and this small amount sustains the entire living world.
• Herbivores (primary consumers) (शाकाहारी (प्राथमिक उपभोक्ता)) — 10 per cent law: only about 10% of the energy of a level reaches the next.
• Primary carnivores (प्राथमिक मांसाहारी) — Secondary consumers; get about 10% of the herbivores’ energy.
• Secondary carnivores (द्वितीयक मांसाहारी) — Very little energy is left — this is why the number of trophic levels in a grazing food chain is limited.
• Heat loss (ऊष्मा हानि) — At every level energy is lost as heat to the environment (second law of thermodynamics). It never comes back — energy flow is unidirectional.
• Decomposers (अपघटक) — When organisms die they become detritus — an energy source for decomposers.

Steps

1. The sun is the source of energy for (almost) all ecosystems.
2. Less than 50% of incident solar radiation is PAR.
3. Plants capture only 2–10% of PAR and store it as food; some energy is lost as heat.
4. Herbivores receive only about 10% (10 per cent law).
5. Primary carnivores get about 10% of that.
6. Secondary carnivores get even less — so food chains stay short.
7. Dead organisms at every level pass energy to decomposers (detritus).

Original diagram drawn by Simple Learning Hub, based on NCERT Fig 12.3. Report a mistake