Environment and Ecosystem
Overview
Environment and Ecosystem is a foundational topic in the Science section of MP TET Varg-2, bridging biology with environmental awareness. Questions typically test your understanding of ecological relationships, energy flow through food chains and webs, types of biodiversity, and the causes and effects of pollution.
This topic carries moderate weightage but is conceptually interconnected with other chapters like Natural Resources and Agriculture. Examiners often frame application-based questions—identifying trophic levels, explaining bioaccumulation, or linking human activities to environmental degradation. Mastery here also supports the pedagogy component, as environmental education is emphasised in NCF 2005 and NEP 2020.
Students must clearly distinguish between related terms (environment vs ecosystem, food chain vs food web), understand energy flow principles, and recognise local examples from Madhya Pradesh's rich biodiversity.
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Key Concepts
- **Environment** refers to all living (biotic) and non-living (abiotic) factors surrounding an organism, while an **ecosystem** is a functional unit where biotic and abiotic components interact through energy flow and nutrient cycling.
- **Biotic components** include producers (green plants), consumers (herbivores, carnivores, omnivores), and decomposers (bacteria, fungi). **Abiotic components** include sunlight, water, temperature, soil, and air.
- **Food chain** is a linear sequence showing "who eats whom" (e.g., Grass → Grasshopper → Frog → Snake → Eagle). **Food web** is an interconnected network of multiple food chains in an ecosystem.
- **Trophic levels** are feeding positions: T1 = Producers, T2 = Primary consumers (herbivores), T3 = Secondary consumers (carnivores), T4 = Tertiary consumers, and so on.
- **10% Law (Lindeman's Law)**: Only about 10% of energy is transferred from one trophic level to the next; the rest is lost as heat through respiration.
- **Biodiversity** refers to the variety of life at three levels: genetic diversity (within species), species diversity (between species), and ecosystem diversity (variety of habitats).
- **Pollution** is the introduction of harmful substances (pollutants) into the environment, classified as air, water, soil, and noise pollution based on the medium affected.
- **Bioaccumulation** is the build-up of toxins in an organism over time; **biomagnification** is the increasing concentration of toxins at higher trophic levels.
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