Extinction
Recap Extinction for GCSE Biology with this free worksheet and full mark scheme — Foundation and Higher exam-style questions with worked answers for AQA, Edexcel and OCR. Extinction occurs when there are no individuals of a species left anywhere; be ready to explain its main causes.
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These worksheets and mark schemes are original, written for Virtus Academy and checked against the current AQA, Edexcel and OCR specifications. Every worksheet comes with a full mark scheme.
Topic overview
Extinction occurs when there are no remaining individuals of a species still alive. It is a permanent loss, not a temporary decline.
Species become extinct for several reasons. The environment may change over geological time. A new predator, a new disease, or a new more successful competitor may appear. A single catastrophic event such as a volcanic eruption or asteroid collision may destroy habitats.
Humans have accelerated extinction through habitat destruction, hunting and pollution. Understanding extinction matters because it connects the topics of natural selection, biodiversity and human impact on ecosystems.
Revision notes
What extinction means
A species is extinct when there are no remaining individuals of that species still alive.
It is permanent. A species reduced to very low numbers is endangered rather than extinct.
Causes of extinction
The environment changes over geological time, and the species cannot adapt quickly enough.
A new predator, disease or more successful competitor appears. A single catastrophic event such as a volcanic eruption or asteroid collision destroys habitats.
Human impact
Habitat destruction, hunting and pollution have greatly increased the rate of extinction.
This links to biodiversity: each extinction reduces the variety of species in an ecosystem and can destabilise it.
Key points
- Extinction means no individuals of a species remain alive.
- It is permanent.
- Environmental change can cause extinction.
- New predators, diseases or competitors can cause extinction.
- Catastrophic events can destroy habitats.
- Human activity has increased extinction rates.
Worked examples
Example 1
Define extinction. [1 mark]
Model answer
Extinction occurs when there are no remaining individuals of a species still alive (1 mark).
Example 2
Give three factors that may lead to the extinction of a species. [3 marks]
Model answer
A change in the environment over geological time (1 mark). The appearance of a new predator, disease or more successful competitor (1 mark). A single catastrophic event such as a volcanic eruption or asteroid collision (1 mark).
Example 3
Explain why a species may become extinct when a new predator is introduced. [2 marks]
Model answer
The species may have no adaptations to defend itself against the new predator (1 mark), so individuals are killed faster than they can reproduce and eventually none remain (1 mark).
Common mistakes
Confusing extinct with endangered.
Endangered means very few remain; extinct means none do.
Giving only human causes.
Natural causes such as environmental change and catastrophic events are also required.
Saying extinction is always sudden.
It may result from gradual environmental change over long periods.
Not explaining the mechanism.
Say why the species could not survive, not just that it died out.
Exam tips
- Use the precise definition — no individuals remaining.
- Give both natural and human causes.
- Explain the mechanism when asked why a species died out.
- Link extinction to biodiversity when the question allows.
Key terms
- Extinction
- When no individuals of a species remain alive.
- Endangered
- When a species has very few individuals remaining.
- Competitor
- Another species using the same resources.
- Catastrophic event
- A sudden event such as a volcanic eruption or asteroid impact.
Related topics
Written and reviewed against the current AQA, Edexcel and OCR specifications. Spotted an error? Let us know.