🆚 In situ vs Ex situ (what to choose?)
Big Idea: Most real conservation uses both approaches. In situ protects ecosystems long-term, while ex situ prevents extinction when the wild is too risky.
In situ
- In the natural habitat
- Protects ecosystems and many species
- Keeps natural behaviours and interactions
- Best long-term if threats can be reduced
Ex situ
- Outside the natural habitat
- Emergency protection for very threatened species
- Supports breeding and genetic storage
- Needs reintroduction and habitat repair
📝 Decision checklist: choosing the best strategy
Use this checklist to justify your choice in evaluation questions.
- Urgency of extinction risk (very high → ex situ backup)
- Habitat condition (intact vs degraded)
- Threat controllability (poaching, invasives, pollution)
- Available space for a viable population
- Genetic diversity potential
- Cost and long-term management capacity
- Local community support and fairness
High marks = name a strategy and justify it using 2–3 checklist points.
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🤝 The strongest strategy is usually a mix
IB examiners reward answers that recognise no single strategy is perfect.
- Step 1: Reduce threats in the wild (laws, enforcement)
- Step 2: Protect and restore habitat (in situ)
- Step 3: Create an ex situ safety net (breeding / seed bank)
- Step 4: Reintroduce and monitor populations
Ex situ alone saves species short-term, but cannot replace habitat protection.
🏆 Exam tips: in situ vs ex situ questions
9-mark structure: Top answers include comparison + evaluation + justified conclusion.
- 1. Define both strategies briefly
- 2. Compare effectiveness (ecosystems vs emergency rescue)
- 3. Evaluate limitations of each
- 4. Apply to context (habitat quality, threat level)
- 5. Conclude with judgement (often a combined strategy)