Endangered species and how to conserve themSpec B16.2.1, B16.2.2
In short
Endangered species risk dying out through habitat loss, hunting or pollution; captive breeding, seed banks and protected reserves help conserve them.
An endangered species is at risk of dying out. A species is extinct when no individuals are left alive anywhere.
Why organisms become endangered or extinct
| Cause | Explanation |
|---|---|
| Climate change | Habitats change too quickly for species to adapt or move |
| Habitat destruction | Loss of food, shelter and breeding sites |
| Hunting | Animals are killed for meat, fur, horns or tusks faster than they reproduce |
| Overharvesting | Plants or animals are collected or caught faster than they can be replaced |
| Pollution | Poisons or waste make habitats unsuitable or kill organisms |
| Introduced species | A non-native species may compete with, prey on or spread disease to native species |
Supplement (what this means)
Supplement: only for the Extended papers (2 and 4). Core students can skip it. What the labels meanHow endangered species can be conserved
Supplement (what this means)
Supplement: only for the Extended papers (2 and 4). Core students can skip it. What the labels mean- Monitoring and protecting species and habitats: populations are counted, and reserves and laws protect the animals and their habitats.
- Education: people are taught why species matter, so they support conservation.
- Captive breeding programmes: animals are bred in zoos and reserves, and young may be released into the wild.
- Seed banks: seeds of rare plants are stored at low temperature so that plants can be grown later if the wild population dies out.
Captive breeding programmes alone do not save a species. The habitat must also be protected so that the animals can be released.
Quick check
Give four reasons why species become endangered or extinct.
Show answer
Any four of: climate change, habitat destruction, hunting, overharvesting, pollution, introduced species.
Supplement What is a seed bank?
Show answer
A store of seeds from rare plants, kept so that the plants can be grown again if wild populations are lost.
Written and checked against the Cambridge IGCSE Combined Science (0653) specification · Updated October 2026