5. Eco System

Eco-System:

Definition and Concept of Eco-System

1. The term 'Ecosystem' was coined by Sir Arthur Tansley in 1935.
2. An ecosystem is a structural and functional unit of nature where living organisms (biotic components) interact with each other and with the non-living (abiotic) environment.
3. It includes all the organisms and the physical environment with which they interact, maintaining a dynamic balance.

Structure & Components of Ecosystem

1. Biotic Components

• Producers (Autotrophs): Mainly green plants and some bacteria that convert solar energy into chemical energy via photosynthesis.
• Consumers (Heterotrophs): Animals and other organisms that consume producers or other consumers (Herbivores, Carnivores, Omnivores).
• Decomposers (Saprotrophs): Microorganisms like bacteria and fungi that break down dead organic matter, recycling nutrients.

2. Abiotic Components

• Physical factors: Sunlight, temperature, water, air, minerals, soil, etc.
• Chemical factors: Nutrients like nitrogen, carbon, phosphorus, etc.
• Climatic factors: Rainfall, humidity, wind, etc.

Functions of Eco-System

1. Productivity

• Primary Productivity: Rate at which producers convert light energy to chemical energy.
• Secondary Productivity: Rate at which consumers convert energy from food into biomass.

2. Energy Flow

• Unidirectional: Solar energy → Producers → Consumers → Decomposers → Environment.
• Only about 10% of energy is transferred to next trophic level (10% law).

3. Nutrient Cycling (Biogeochemical Cycles)

• Continuous cycling of elements (carbon, nitrogen, phosphorus, water, etc.) between biotic and abiotic components.

4. Decomposition

• Breakdown and recycling of organic matter, replenishing nutrients.

5. Regulation (Homeostasis)

• Ecosystem maintains a balance through negative feedback mechanisms.

Types of Eco-System

1. Natural Ecosystems

• Terrestrial Ecosystems: Forests, grasslands, deserts, tundra.
• Aquatic Ecosystems: Freshwater (ponds, lakes, rivers), Marine (oceans, estuaries).

2. Artificial Ecosystems

• Created or modified by humans: Crop fields, aquariums, urban parks.

Key Concepts in Ecosystem

1. Food Chain

• Linear sequence of organisms where one is eaten by the next in the chain. E.g., Grass → Grasshopper → Frog → Snake → Hawk.

2. Food Web

• Network of interconnected food chains, depicting complex feeding relationships.

3. Ecological Pyramids

• Graphical representation of number, biomass or energy at each trophic level (Pyramid of Numbers, Biomass, Energy).

4. Trophic Levels

• Producers → Primary consumers → Secondary consumers → Tertiary consumers → Decomposers.

5. Ecological Succession

• Gradual and sequential change in species composition in an ecosystem over time (primary and secondary succession).

Ecosystem Services

1. Provisioning Services: Food, water, timber, fiber, medicine.
2. Regulating Services: Climate regulation, disease control, water purification, pollination.
3. Supporting Services: Nutrient cycling, soil formation, primary production.
4. Cultural Services: Recreation, spiritual and aesthetic benefits.

Importance of Ecosystem

1. Maintains ecological balance and supports life on Earth.
2. Supplies raw materials and resources for survival and development.
3. Regulates biogeochemical cycles and climate.
4. Protects against environmental hazards and disasters.

Threats to Ecosystems

1. Deforestation and habitat loss.
2. Pollution (air, water, soil).
3. Climate change and global warming.
4. Overexploitation of resources.
5. Introduction of invasive species.

Conservation and Preservation Strategies

1. Protected areas (National Parks, Wildlife Sanctuaries).
2. Afforestation and reforestation.
3. Sustainable resource utilization.
4. Environmental Impact Assessment (EIA).
5. Restoration ecology.

Conclusion

• India is rich in diverse ecosystems (Western Ghats, Himalayas, Sundarbans, etc.).
• Ecosystem-based approaches are included in government schemes like PMKSY, National Afforestation Programme, etc., to balance development with conservation.

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