Environment, Ecology & Biodiversity – Concise Revision Notes
Tailored for JKSSB Accounts Assistant (Finance) – General Knowledge
These structured notes cover key concepts, definitions, and facts for efficient revision.
1. Environment – Basic Concepts
Definition: The sum total of all external conditions (biotic & abiotic) that influence the life, development, and survival of an organism.
Components
- Biotic: Living organisms (plants, animals, microbes).
- Abiotic: Non‑living factors (temperature, light, water, soil, atmosphere, nutrients).
Key Highlights
- Environment = Habitat + Niche (the role of an organism).
- Homeostasis: Self‑regulating processes that keep internal conditions stable despite external changes.
2. Ecology – Study of Interactions
Definition: Scientific study of the relationships between living organisms and their environment.
Hierarchy of Ecological Organization
- Organism
- Population
- Community
- Ecosystem
- Biome
- Biosphere
Core Principles
- Energy Flow: Unidirectional (sun → producers → consumers → decomposers).
- Material Cycling: Nutrients move in biogeochemical cycles (Carbon, Nitrogen, Phosphorus, Sulfur, Water).
- Population Dynamics: Governed by birth, death, immigration, emigration, and carrying capacity (K).
- Succession: Progressive change in species composition.
- Primary: On bare rock.
- Secondary: After a disturbance.
Useful Mnemonics
- Trophic Levels: “Please Eat Meat, but Don’t Forget Veggies” → Producers, Erst (Primary) consumers, Meat (Secondary) consumers, Don’t (Tertiary) consumers, Forget (Decomposers) Veggies.
- Biogeochemical Cycles: “Cats NAP in Water” → Carbon, Nitrogen, Aphosphorus (actually P), Water.
3. Ecosystem – Structure & Function
| Aspect | Description |
|---|---|
| Structure | Abiotic (climate, soil, water) + Biotic (producers, consumers, decomposers). |
| Function | Energy flow, nutrient cycling, ecological stability, productivity. |
| Productivity | Gross Primary Productivity (GPP) – total solar energy captured. Net Primary Productivity (NPP) – GPP minus plant respiration (energy available to herbivores). |
| Ecological Pyramids | Pyramid of Numbers (often inverted), Biomass (usually upright), Energy (always upright, 10 % rule). |
Types of Ecosystems
| Category | Examples (India) | Salient Features |
|---|---|---|
| Terrestrial | Tropical rainforest (Western Ghats), Deciduous forest (Central India), Thorn forest (Rajasthan), Grassland (Tarai), Desert (Thar), Alpine tundra (Himalayas) | Defined by precipitation & temperature; vegetation determines fauna. |
| Freshwater (Lentic) | Lakes (Dal, Wular), Ponds, Swamps | Standing water; stratification (epilimnion, metalimnion, hypolimnion). |
| Freshwater (Lotic) | Rivers (Ganga, Brahmaputra), Streams | Flowing water; high oxygen, continuous nutrient renewal. |
| Marine | Coral reefs (Andaman & Nicobar), Estuaries (Sundarbans), Open ocean, Deep sea | Salinity ~35 %; high biodiversity in coral reefs; estuaries act as nurseries. |
| Artificial | Reservoirs, Aquaculture ponds, Urban parks | Man‑modified; often require management for sustainability. |
4. Biodiversity – Variety of Life
Definition: Variability among living organisms from all sources, including terrestrial, marine, and other aquatic ecosystems, and the ecological complexes of which they are part.
Levels of Biodiversity
| Level | What it Means | Examples |
|---|---|---|
| Genetic | Variety of genes within a species. | Different rice varieties (Basmati, IR64). |
| Species | Variety of species within a region. | Bengal tiger, Indian one‑horned rhinoceros. |
| Ecosystem | Variety of habitats, communities, ecological processes. | Mangroves, coral reefs, grasslands. |
Mnemonic: “GSE” → Genetic, Species, Ecosystem.
Importance of Biodiversity
- Ecological: Stabilizes ecosystems, provides resilience.
- Economic: Source of food, medicine, fibers, tourism (ecotourism).
- Cultural: Spiritual, aesthetic, traditional knowledge.
- Scientific: Basis for research, biotechnology, climate regulation.
5. Biodiversity Hotspots
Criteria (Myers et al., 2000):
- ≥ 1,500 endemic vascular plant species (>0.5 % of world’s total).
- ≥ 70 % loss of original habitat.
World Hotspots (36)
Notable ones: Mediterranean Basin, California Floristic Province, Madagascar & Indian Ocean Islands, Sundaland, Western Ghats & Sri Lanka, Himalaya, Indo‑Burma.
India’s Hotspots (4 Recognised)
- Western Ghats & Sri Lanka – Endemic amphibians, Shola grasslands.
- Eastern Himalayas – High species richness of orchids, rhododendrons.
- Indo‑Burma (North‑East) – Mammals like Hoolock gibbon, rare birds.
- Sundaland (Nicobar Islands) – Coral reefs, mangroves.
Key Highlight: Protecting hotspots yields disproportionate conservation benefits as they harbour a large fraction of endemic species under severe threat.
6. Threats to Biodiversity
| Threat | Mechanism | Examples in India |
|---|---|---|
| Habitat Loss & Fragmentation | Conversion to agriculture, urbanization, mining. | Deforestation in Northeast, wetland conversion. |
| Overexploitation | Unsustainable hunting, fishing, logging. | Poaching of tigers, overfishing. |
| Invasive Alien Species | Outcompete natives, alter habitats. | Lantana camara, African catfish. |
| Pollution | Chemical load degrades water/soil/air. | Industrial effluents in Yamuna, plastic in Ganges. |
| Climate Change | Shifts in temperature/precipitation, phenology mismatch. | Glacier retreat, coral bleaching in Andaman. |
| Disease | Pathogens spill over from livestock/humans. | Chytrid fungus affecting amphibians. |
7. Conservation Strategies
7.1 In‑Situ Conservation (Protected Areas)
| Category | Legal Status (India) | Examples |
|---|---|---|
| National Park | Strict protection; no human habitation. | Jim Corbett (Uttarakhand), Kaziranga (Assam). |
| Wildlife Sanctuary | Limited human activities allowed. | Periyar (Kerala), Ranthambhore (Rajasthan). |
| Biosphere Reserve | Core zone (strict), buffer (limited use), transition (sustainable). | Nilgiri, Sundarbans, Nanda Devi. |
| Community Reserve | Managed by local communities for wildlife. | Khonoma (Nagaland), Tawang (Arunachal Pradesh). |
| Conservation Reserve | Buffer zones around PAs, managed for wildlife. | Kodaikanal (Tamil Nadu). |
Mnemonic: “PANCS” → Parks, Allied Sanctuaries, National Parks, Community Reserves, Sanctuaries (or Biosphere).
7.2 Ex‑Situ Conservation
| Method | Purpose | Examples |
|---|---|---|
| Zoos & Aquariums | Captive breeding, education. | Delhi Zoo, Chennai Snake Park. |
| Botanical Gardens | Germplasm preservation, research. | Indian Botanic Garden (Kolkata), NBRI (Lucknow). |
| Seed Banks | Long‑term storage of plant genetic resources. | National Bureau of Plant Genetic Resources (NBPGR), New Delhi. |
| Cryopreservation | Storage of gametes/embryos at ultra‑low temps. | Buffalo semen bank, fish sperm banks. |
| Gene Banks | DNA libraries for future breeding. | International Rice Research Institute (IRRI) germplasm. |
7.3 Policy & Legislative Framework (India)
| Act / Policy | Year | Core Provision |
|---|---|---|
| Wildlife Protection Act | 1972 | Protects wild animals, birds, plants; establishes PAs. |
| Forest (Conservation) Act | 1980 | Requires central approval for non‑forest use of forest land. |
| Environment Protection Act | 1986 | Umbrella act; empowers central govt to protect environment. |
| Biological Diversity Act | 2002 | Implements CBD; sets up National Biodiversity Authority (NBA), State Biodiversity Boards (SBBs), Biodiversity Management Committees (BMCs). |
| National Wildlife Action Plan (NWAP) | 2017‑2031 | Landscape‑based conservation, climate‑change integration, community participation. |
| National Biodiversity Action Plan (NBAP) | 2008 (updated 2014) | 12 national targets aligned with Aichi Biodiversity Targets. |
| Green India Mission | 2010 (under NAPCC) | Increase forest/tree cover, improve ecosystem services, livelihoods. |
| National Clean Air Programme (NCAP) | 2019 | Reduce particulate matter (PM2.5/PM10)
|