Environment: Ecology Principles and the Legal Framework
Environment questions combine ecological principles with the Indian legal and international framework for conservation. Learn the principle, then the instrument that protects it.
Principles to know cold
- Levels of organisation: individual → population → community → ecosystem → biome → biosphere.
- Food chain and food web; trophic levels; the 10% law; pyramids of number, biomass and energy - the energy pyramid is always upright.
- Biotic interactions: mutualism, commensalism, parasitism, predation, competition.
- Biogeochemical cycles: carbon, nitrogen, oxygen, water; nitrogen fixation by Rhizobium and cyanobacteria.
- Succession: hydrarch (wet to dry) and xerarch (dry to wet); pioneer and climax communities.
- Biodiversity: in-situ (national parks, sanctuaries, biosphere reserves) vs ex-situ (zoo, botanical garden, seed bank); India's four hotspots - Himalaya, Western Ghats, Indo-Burma, Sundaland (Nicobar).
Law and policy
Wildlife (Protection) Act 1972; Forest (Conservation) Act 1980; Environment (Protection) Act 1986, the umbrella law that followed Bhopal; Biological Diversity Act 2002; Forest Rights Act 2006. International: Ramsar Convention on wetlands (1971), CITES on wildlife trade, CBD (1992), UNFCCC and the Paris Agreement.
Worked example
Grassland producers fix 10,000 kJ. How much reaches the tertiary consumer? Each transfer keeps 10%: primary consumer 1,000 kJ, secondary 100 kJ, tertiary 10 kJ - three transfers, so 10 kJ. Count the number of steps, not the number of animals.
Traps
- Ramsar = wetlands, CITES = trade, CBD = biodiversity; options shuffle these.
- The ozone hole is a stratospheric CFC problem, distinct from the greenhouse effect.
- In-situ and ex-situ reversed.
- High BOD means polluted water; high DO means clean water - the pair is inverted in options.