This deep dive covers Extinction within Evolution for GCSE Biology. Theory of evolution, natural selection, and evidence for evolution It is section 7 of 13 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 7 of 13
Practice
26 questions
Recall
25 flashcards
🦕 Extinction
Extinction is the permanent loss of all members of a species — there are none left alive anywhere on Earth.
Causes of Extinction
- Habitat destruction — deforestation, urbanisation, and farming remove the places organisms live and breed
- New diseases — a pathogen can wipe out a species that has no resistance
- New predators or competitors — introduced species can outcompete native ones for food and resources
- Climate change — changes in temperature or rainfall can happen faster than species can adapt
- Hunting and overexploitation — humans hunting faster than populations can reproduce (e.g. dodo, passenger pigeon)
- Catastrophic events — volcanic eruptions, asteroid impacts, ice ages can cause mass extinctions
Why Extinction Matters
Every species lost reduces biodiversity — the variety of life on Earth. Lower biodiversity makes ecosystems less stable and less able to recover from change. Once a species is extinct, its unique genes are lost forever.