Question
Differentiate between in situ and ex situ conservation. Give examples of each. What are biosphere reserves, national parks, and wildlife sanctuaries? How do they differ?
(NCERT Class 12 — directly asked in NEET and CBSE boards)
Solution — Step by Step
In situ (Latin: “in place”) means conserving organisms in their natural habitat.
| Type | Description | Example |
|---|---|---|
| National parks | Strictly protected; no human activity (grazing, forestry) allowed | Jim Corbett (Uttarakhand), Kaziranga (Assam), Gir (Gujarat) |
| Wildlife sanctuaries | Some human activities allowed (grazing, timber collection with permission) | Bharatpur Bird Sanctuary (Rajasthan), Periyar (Kerala) |
| Biosphere reserves | Large areas with core zone (no activity), buffer zone (limited activity), transition zone (human settlements) | Nilgiri, Nanda Devi, Sundarbans, Gulf of Mannar |
| Sacred groves | Forest patches protected by tribal communities on religious grounds | Khasi and Jaintia hills (Meghalaya), Aravali hills (Rajasthan) |
India has 106 national parks, 567 wildlife sanctuaries, and 18 biosphere reserves.
Ex situ (Latin: “off site”) means conserving organisms outside their natural habitat in controlled environments.
| Type | Description | Example |
|---|---|---|
| Zoos | Live animals maintained in captivity; breeding programmes | Delhi Zoo, Mysore Zoo |
| Botanical gardens | Collections of living plants | Indian Botanical Garden (Kolkata), Kew Gardens (UK) |
| Seed banks | Seeds stored at low temperature for long-term preservation | National Bureau of Plant Genetic Resources (NBPGR), New Delhi |
| Cryopreservation | Gametes, embryos stored in liquid nitrogen (-196°C) | Used for endangered species’ genetic material |
| Tissue culture | Plants propagated from small tissue pieces in labs | Orchids, endangered medicinal plants |
| Feature | In situ | Ex situ |
|---|---|---|
| Location | Natural habitat | Artificial/controlled environment |
| Scale | Protects entire ecosystem | Protects individual species |
| Cost | Lower per species | Higher per species |
| Genetic diversity | Maintained (natural breeding) | May decrease (small populations) |
| Examples | National parks, sanctuaries | Zoos, seed banks, botanical gardens |
Why This Works
In situ conservation is preferred because it protects not just individual species but the entire ecosystem — the habitat, food web, and ecological relationships. An animal in a zoo survives but doesn’t contribute to its ecosystem.
Ex situ conservation serves as a backup — when a species is critically endangered and may go extinct in the wild, captive breeding and seed banks preserve its genetic material. The ideal strategy combines both: breed in captivity (ex situ), then reintroduce into protected habitats (in situ).
Alternative Method — Protected Areas Quick Facts
For NEET, remember these distinctions:
- National park → Strictest protection. No human activity. Government-owned.
- Wildlife sanctuary → Some activities permitted. Can include private land.
- Biosphere reserve → Largest. Three zones (core, buffer, transition). May contain national parks and sanctuaries within them.
NEET often asks: “Which type of protected area allows limited human activity?” Answer: Wildlife sanctuary (not national park).
Common Mistake
Students confuse national parks with wildlife sanctuaries. The critical difference: national parks have stricter protection — no human habitation or activities like grazing are permitted. Wildlife sanctuaries allow limited human activities with government permission. Also, sacred groves are an often-forgotten example of in situ conservation. NEET has asked about sacred groves in Meghalaya (Khasi hills) — don’t miss this NCERT point.