Cheat sheet · NEET Preparation Botany
Ecosystem cheat sheet
The whole chapter on one page: key formulas, facts and the points to remember, for quick revision before a test.
NEET · Botany
Cheat sheet
Class 12 · Chapter 12Ecosystem
10% law: only about 10% of energy passes to the next trophic level.
1. Productivity
Annual NPP of biosphere ≈ 170 billion tonnes (dry weight); oceans ~55.
2. Decomposition
Fragmentation → leaching → catabolism → humification → mineralisation.
Faster when warm and moist; slower with lignin and chitin.
3. Energy Flow & Pyramids
- Unidirectional flow; grazing and detritus food chains.
- Pyramid of energy is always upright.
- Pyramid of biomass is inverted in the sea; pyramid of numbers inverted for a tree.
4. Succession
- Primary (bare rock) vs secondary (after disturbance).
- Pioneer species: lichens (xerarch), phytoplankton (hydrarch).
- Ends in a climax community.
5. Key Points
- Producers fix only 2–10% of PAR.
- Phosphorus cycle has no gaseous phase.
- Ecosystem services: pollination, purification.
- Standing crop = biomass at a time.
Remember: GPP/NPP | decomposition steps | pyramids | succession
Ecosystem: questions and notes
More NEET Preparation Botany cheat sheets
- The Living World
- Biological Classification
- Plant Kingdom
- Morphology of Flowering Plants
- Anatomy of Flowering Plants
- Cell: The Unit of Life
- Cell Cycle and Cell Division
- Photosynthesis in Higher Plants
- Respiration in Plants
- Plant Growth and Development
- Sexual Reproduction in Flowering Plants
- Principles of Inheritance and Variation
- Molecular Basis of Inheritance
- Microbes in Human Welfare
- Organisms and Populations
- Ecosystem
- Biodiversity and Conservation
Practise Ecosystem
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