1.6.5Additional lessons
How to Preserve Biodiversity — IB Biology SL Revision Notes & Topical Questions
5 min read 4 parts Lesson 10 of 142
Curriculum Equation Key قوانين الرقم الهيدروجيني والاتزان الأيوني - pH & Acid-Base Equilibrium FormulasFast Exam Solution
pH = -log[H⁺] | pOH = -log[OH⁻] | pH + pOH = 14 | [H⁺][OH⁻] = 10⁻¹⁴
Word Equation & Conditions: الرقم الهيدروجيني = -لوغاريتم تركيز أيون الهيدروجين | pH + pOH = 14
Location & Specifications: الاتزان الأيوني، كيمياء 3 ثانوي، التحصيلي، و AP Chemistry.
Part 1 of 4In Situ Conservation
Definition
- Definition Conservation in the natural habitat of the species, so that it keeps its ecological relationships and natural selection pressures.
Protected areas
- Protected areas National parks and reserves limit hunting, building and farming, and control human access to reduce disturbance.
Rewilding
- Rewilding Restoring ecosystems to a former natural state, either actively by reintroducing species or passively by leaving land to recover.
Reclamation
- Reclamation Repairing land damaged by mining, farming or dumping so that native vegetation and animals can return.
Benefit
- Benefit Protecting a whole habitat conserves many species together and keeps genetic diversity within wild populations.
Limits
- Limits Protected areas need enforcement and enough space, otherwise poaching, pollution and edge effects still reduce biodiversity.
Part 2 of 4Ex Situ Conservation
Ex situ methods conserve species outside their natural habitat.
Ex Situ Conservation
Zoos
- Zoos Captive breeding can build up numbers of rare animals, and zoos also carry out research and education.
Botanic gardens
- Botanic gardens Living collections of plants are grown and studied, and gardens can propagate threatened plants for reintroduction.
Seed banks
- Seed banks Seeds are dried and stored at low temperature, which preserves large numbers of plant genotypes in a small space.
Tissue banks
- Tissue banks Germplasm such as sperm, eggs and embryos, or somatic tissue, is kept frozen to preserve genetic material.
| Feature | In situ | Ex situ |
|---|---|---|
| Location | Natural habitat | Zoo, garden or bank |
| Species interactions | Maintained | Largely lost |
| Risk | Habitat can still be damaged | Captive breeding may reduce genetic variation |
| Best use | Whole ecosystems | Species too rare to survive in the wild |
Part 3 of 4Choosing Priority Species
1
Resources for conservation are limited, so decisions are needed about which species receive protection first.
2
The EDGE approach ranks species that are Evolutionarily Distinct, meaning they have few close relatives and unusual features.
3
It also considers how Globally Endangered the species is, using its IUCN Red List category.
4
Species that score highly on both, such as the largetooth sawfish, Chinese giant salamander and purple frog, become priorities.
5
Prioritising raises ethical questions because choosing some species over others also means other species receive less help.
Part 4 of 4Exam Checklist & Tips
1.6.5 – Key Points for the Exam
- In situ conservation Protecting species in their natural habitat.
- Ex situ conservation Protecting species outside their natural habitat, for example in zoos or seed banks.
- Rewilding Restoring ecosystems towards a natural state, sometimes by reintroducing lost species.
- Seed bank A facility storing seeds in cold, dry conditions to preserve plant genetic diversity.
- EDGE species Species that are evolutionarily distinct and globally endangered.
Common Mistakes
- Stating that zoos are in situ because they protect animals; they are ex situ.
- Forgetting that captive populations can lose genetic diversity when numbers are very small.
- Treating rewilding as simply doing nothing; some projects actively reintroduce species or remove barriers.
- Saying EDGE only counts endangered status; it also needs evolutionary distinctness.
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