ECOSYSTEM - Complete NEET Guide
20-Year NEET Trends Analysis + NCERT Based PYQs (2004-2024)
🌿 3 MUST-KNOW FACTS FOR NEET 2025
🌱 ECOSYSTEM COMPONENTS - NEET NCERT Highlights
| Component Type | Key Concept | NEET Example |
|---|---|---|
| Abiotic | Non-living physical & chemical factors | Temperature, light, pH (NEET 2019) |
| Producers | Autotrophs (Photo/Chemo-synthesis) | Green plants, Cyanobacteria (NEET 2021) |
| Consumers | Heterotrophs (Herbivores, Carnivores) | Food chain levels (NEET 2017) |
| Decomposers | Break down organic matter | Bacteria, Fungi (NEET 2020) |
NEET 2025 Tip: Remember the 3 main ecosystem types - Terrestrial, Aquatic (Freshwater & Marine), and Artificial (asked 7 times in last decade)
☀️ PRODUCTIVITY
- Primary Productivity: Rate of biomass production
- GPP vs NPP: GPP - Respiration = NPP
- NEET Focus: Ocean productivity highest in coral reefs (NEET 2016, 2022)
- Limiting Factors: Light, Temperature, Nutrients
♻️ DECOMPOSITION
- Process Steps: Fragmentation, Leaching, Catabolism, Humification, Mineralization
- Factors Affecting: Oxygen, Moisture, Temperature
- NEET Favorite: Detritus food chain starts with decomposers (NEET 2018, 2021, 2023)
- Importance: Nutrient cycling back to ecosystem
⚡ ENERGY FLOW & ECOLOGICAL PYRAMIDS
Energy Flow - 10% Law
- Unidirectional: Sun → Producers → Consumers
- 10% Rule: Only 10% energy transferred between trophic levels
- NEET Example: Food chain with 4 levels - energy at 4th level? (NEET 2019)
Ecological Pyramids
- Pyramid of Energy: Always upright (NEET favorite)
- Pyramid of Biomass: Inverted in aquatic
- Pyramid of Numbers: Can be inverted (parasitic food chain)
- NEET Special: Compare all three pyramids (NEET 2020, 2022)
NEET Special: Remember exceptions - Pyramid of biomass inverted in aquatic, Pyramid of numbers inverted in parasitic food chains
🌳 ECOLOGICAL SUCCESSION & NUTRIENT CYCLING
Ecological Succession:
- Primary: Bare area to climax community
- Secondary: After disturbance
- Pioneer Species: Lichens in primary
- Climax Community: Stable final stage
- NEET Focus: Hydrarch vs Xerarch succession (NEET 2021)
Nutrient Cycling - NEET Pattern:
- Carbon Cycle: Photosynthesis & Respiration
- Nitrogen Cycle: Nitrogen fixation, Nitrification, Denitrification
- Phosphorus Cycle: Sedimentary cycle (no gaseous phase)
- NEET Favorite: Rhizobium role in N2 fixation (NEET 2020)
NEET Must-Know: Difference between Gaseous (C, N) and Sedimentary (P) cycles - Asked 4 times in last 5 years
📜 NEET PYQ TRENDS (2014-2024)
2023: Which ecological pyramid is always upright?
Pyramid of Energy (Correct Answer)
2021: In aquatic ecosystem, which pyramid is inverted?
Pyramid of Biomass (NCERT based)
2019: What percentage of energy is transferred between trophic levels?
10% (Direct NCERT line)
