NEET Biology Ecosystem 2027 — Energy Flow and Food Chains
Ecosystem chapter (NCERT Class 12, Chapter 14) is a NEET favourite. Questions test understanding of energy flow, trophic levels, productivity, decomposition, and ecological pyramids — all clearly explained in NCERT.
Energy Flow — Key Concepts
| Concept | Key Fact |
|---|---|
| 10% Law | Only 10% energy transferred to next trophic level (Lindeman, 1942) |
| GPP vs NPP | NPP = GPP – Respiration losses |
| Standing Crop | Mass of living organisms per unit area at any time |
| Decomposition | Fragmentation → Leaching → Catabolism → Humification → Mineralisation |
| Detritivores | Earthworm, millipede, dung beetle — break detritus physically |
Ecological Pyramids — NEET Favourites
Three types: Number, Biomass, Energy. Remember:
- Pyramid of Energy — ALWAYS upright (never inverted)
- Pyramid of Biomass in Sea — Inverted (phytoplankton biomass less than zooplankton)
- Pyramid of Numbers in Parasitic chain — Inverted (one tree supports many insects)
Carbon cycle: reservoir = atmosphere (CO₂) | Nitrogen cycle: reservoir = atmosphere (N₂) | Phosphorus cycle: reservoir = sediment/rock (SEDIMENTARY — no atmospheric phase) | Water cycle: reservoir = oceans
Important NEET Questions from This Chapter
Previous year patterns show: ~2-3 questions on energy flow, 1-2 on decomposition, 1 on biogeochemical cycles, 1-2 on ecological pyramids. The NCERT text and diagrams are sufficient — no need for extra reference books.
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