Environment & Ecology: Quick Notes for 2-3 Guaranteed Questions
Environment and Ecology gives you 2-3 questions in almost every competitive exam — and these are questions that most students skip during preparation because they think it's too 'science-heavy.' The truth? Exam questions on environment are mostly about definitions, international agreements, and India-specific facts. No complex biology needed. Read these notes carefully, revise them in the app before your exam, and pick up those easy marks that others leave on the table.
Ecosystem Basics: Food Chain, Trophic Levels & Energy
An ecosystem is a community of living organisms interacting with their physical environment. Food Chain: the linear path of energy — Grass → Grasshopper → Frog → Snake → Eagle. Food Web: multiple interconnected food chains in an ecosystem (more realistic). Trophic Levels: Producers (plants, T1) → Primary Consumers (herbivores, T2) → Secondary Consumers (small carnivores, T3) → Tertiary Consumers (top predators, T4). The 10% Energy Rule (Lindeman's rule): Only 10% of energy transfers from one trophic level to the next. So if plants have 10,000 joules, herbivores get 1,000, small carnivores get 100, and top predators get only 10. This is why food chains are rarely longer than 4-5 levels. Exam favorite: '10% rule' and 'who proposed it' (Raymond Lindeman, 1942).
Biodiversity Hotspots & Forest Types of India
India has 4 Biodiversity Hotspots (out of 36 globally): 1) Western Ghats — richest biodiversity, includes Kerala, Karnataka, Tamil Nadu hill regions. 2) Eastern Himalayas — includes Northeast India, Nepal, Bhutan. 3) Indo-Burma — includes Northeast India (Manipur, Mizoram), Myanmar. 4) Sundaland — includes Nicobar Islands. Exam trick: India's hotspots = 'WE IS' (Western Ghats, Eastern Himalayas, Indo-Burma, Sundaland). Major forest types in India: Tropical Evergreen (heavy rainfall areas — Western Ghats, Northeast), Tropical Deciduous (most widespread — teak, sal), Mangrove Forests (Sundarbans is the largest — Royal Bengal Tiger), Thorn Forests (Rajasthan, Gujarat — dry areas), Alpine/Montane (high altitudes — Himalayas). Sundarbans is a UNESCO World Heritage Site — frequently asked.
International Agreements: The Big 5 for Exams
These 5 international environmental agreements are asked repeatedly: 1) Paris Agreement (2015): Signed at COP21, aims to limit global warming to 1.5°C above pre-industrial levels. India committed to reducing carbon intensity. Replaced Kyoto Protocol targets. 2) Kyoto Protocol (1997, enforced 2005): First legally binding climate treaty. Set emission reduction targets for developed nations. India was exempt as a developing country. 3) Montreal Protocol (1987): To protect the ozone layer by phasing out CFCs and other ozone-depleting substances. Considered the most successful environmental treaty ever. 4) CITES (Convention on International Trade in Endangered Species): Regulates trade in endangered wildlife. Also called the Washington Convention (1973). 5) Ramsar Convention (1971, Iran): For the conservation of wetlands. India has 80+ Ramsar sites — the number keeps increasing, so check latest. Important Ramsar sites: Chilika Lake (Odisha), Wular Lake (J&K — largest freshwater lake in India), Loktak Lake (Manipur — only floating national park), Sambhar Lake (Rajasthan — largest saltwater lake).
Pollution, Climate Terms & Indian Environmental Laws
Pollution types and key terms: Air Pollution — NAAQS (National Ambient Air Quality Standards) set by CPCB (Central Pollution Control Board). AQI (Air Quality Index) ranges from 0-500. PM2.5 and PM10 are the key pollutants measured. Water Pollution — BOD (Biochemical Oxygen Demand) measures organic pollution; high BOD = more polluted. COD (Chemical Oxygen Demand) measures total organic + inorganic pollution. Noise Pollution — Residential limit: 55 dB (day), 45 dB (night). Industrial limit: 75 dB (day), 70 dB (night). Climate terms: Carbon Footprint (total CO2 emissions by an individual/organization), Greenhouse Gases (CO2, Methane, N2O, CFCs — trap heat in atmosphere), Global Warming (increase in Earth's average temperature), Ozone Layer (in Stratosphere, absorbs UV rays, 'ozone hole' over Antarctica).
Indian Environmental Laws — learn the years and names: Wildlife Protection Act, 1972 (protects wild animals and birds, established National Parks and Sanctuaries). Forest Conservation Act, 1980 (restricts diversion of forest land for non-forest purposes). Environment Protection Act, 1986 (umbrella legislation after Bhopal Gas Tragedy, gives Central Government power to protect environment). Water (Prevention & Control of Pollution) Act, 1974. Air (Prevention & Control of Pollution) Act, 1981. National Green Tribunal (NGT) established in 2010 for effective disposal of environment-related cases. Exam hack: remember the years in order — 1972, 1974, 1980, 1981, 1986 — Wildlife, Water, Forest, Air, Environment. These 2-3 questions on environment could be the difference between clearing the cutoff and missing it by one mark. Don't leave them to luck — use the app's daily quiz to keep these facts fresh in your mind!