Environment and Ecology

Overview

Environment and Ecology forms a critical component of the KTET Category II/III Science section, testing your understanding of how living organisms interact with each other and their physical surroundings. This topic bridges biology with real-world environmental concerns, making it both conceptually important and practically relevant.

For KTET, expect questions on ecosystem components and functions, food chains and webs, types of biodiversity, major pollutants and their effects, and conservation strategies. Kerala's unique ecological features—Western Ghats biodiversity hotspot, backwater ecosystems, and coastal environments—often appear in context-based questions. Mastering this topic requires understanding interconnections rather than memorising isolated facts.

Key Concepts

• **Ecosystem** is a functional unit comprising living organisms (biotic) and non-living environment (abiotic) interacting as a system. Examples: pond ecosystem, forest ecosystem, Kerala backwaters.

• **Biotic components** include producers (green plants), consumers (herbivores, carnivores, omnivores), and decomposers (bacteria, fungi). Abiotic components include sunlight, temperature, water, soil, and minerals.

• **Food chain** shows linear transfer of energy from producers to consumers. Food web is interconnected food chains showing complex feeding relationships in an ecosystem.

• **Ecological pyramid** represents trophic levels graphically—pyramid of numbers, pyramid of biomass, and pyramid of energy. Energy pyramid is always upright (10% law: only 10% energy transfers to next level).

• **Biodiversity** refers to variety of life at three levels: genetic diversity (within species), species diversity (between species), and ecosystem diversity (variety of habitats).

• **Biogeochemical cycles** are pathways through which elements like carbon, nitrogen, and water circulate between living organisms and environment.

• **Pollution** is introduction of harmful substances into environment. Types: air, water, soil, and noise pollution.

• **Conservation** includes in-situ (national parks, sanctuaries) and ex-situ (zoos, seed banks) methods of protecting biodiversity.

Formulas / Key Facts

| Concept | Key Fact | |---------|----------| | Energy flow | Only 10% energy passes from one trophic level to next (Lindeman's 10% Law) | | Oxygen in atmosphere | 21% of atmospheric composition | | CO₂ in atmosphere | Approximately 0.04% (increasing due to human activities) | | India's biodiversity | 12 mega-biodiversity countries; India is one of them | | Western Ghats | UNESCO World Heritage Site; one of 36 global biodiversity hotspots | | Silent Valley | Kerala's only national park with tropical rainforest; saved from hydroelectric project | | Periyar Tiger Reserve | Located in Idukki and Pathanamthitta districts of Kerala | | Ramsar Sites in Kerala | Vembanad-Kol wetland and Ashtamudi wetland | | Ozone layer | Found in stratosphere; protects from UV radiation | | BOD (Biochemical Oxygen Demand) | Higher BOD indicates more polluted water |