Extinction — AQA GCSE Biology
Test yourself on Extinction with AQA GCSE practice questions.
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Extinction explained
Extinction means no members of a species remain alive anywhere.
Read the full explanation
Several factors can contribute, often acting together. A new predator or competitor may outcompete native species for food and territory. A new disease can spread rapidly through a population with little resistance. Environmental change, such as climate shifts, drought or habitat destruction, may remove breeding sites and food sources. Human activity, including deforestation, pollution and overhunting, accelerates these pressures. For example, introduced rats on islands prey on ground-nesting birds, while habitat loss removes their nesting cover, so the population cannot replace itself and eventually disappears. Describing means naming each factor and explaining how it reduces numbers until reproduction fails and the species is lost.
Your focus
- State at least three factors that may contribute to extinction.
- Explain how a named factor reduces a population until the species is lost.
- Apply the concept to an unfamiliar example and predict the likely outcome.
Extinction exam tips
Marking Points
- Identifies a named factor such as a new predator, competitor, disease, environmental change or human activity.
- Explains the mechanism by which the factor reduces the population, for example competition for limited food or destruction of breeding habitat.
- Links the factor to a fall in population size until no breeding individuals remain.
- Uses a specific example, such as an introduced predator or habitat loss, to support the description.
- Recognises that several factors often act together rather than in isolation.
Examiner Tips
- 💡Use the command word describe: give clear points about each factor and how it acts.
- 💡Support each factor with a brief named example to show understanding.
- 💡Link factors to population decline and loss of breeding, not just to harm to individuals.
Common Mistakes
- Confusing extinction with a species becoming endangered; the correction is that extinction means no living members remain.
- Treating a single factor as always sufficient; the correction is that factors often combine and interact.
- Describing extinction as an instant event; the correction is that it is usually a gradual decline over generations.