AQA GCSE · Question 07.6 · Inheritance Variation and Evolution
Trilobites A and B are now extinct. Give three possible causes of extinction.
How to approach this question
Think about major changes that could wipe out an entire species. These can be sudden events or gradual changes. Consider changes to the physical environment, the arrival of new organisms, or catastrophic events from space. List three distinct possibilities.
Full Answer
Extinction is the permanent loss of a species. It can be caused by a variety of factors:
- **Environmental Change:** Gradual or rapid changes in climate (e.g., an ice age or global warming) can make a habitat unsuitable for a species that cannot adapt quickly enough.
- **New Competitors:** A new species might evolve or be introduced that outcompetes the existing species for food, water, or shelter.
- **New Predators:** The evolution or arrival of a new, efficient predator can wipe out a prey species that has no effective defence.
- **New Diseases:** A new pathogen can spread through a species that has no immunity, causing mass death.
- **Catastrophic Events:** A single major event, such as a large asteroid impact or a massive volcanic eruption, can cause widespread destruction and rapid climate change, leading to mass extinctions.
Common mistakes
✗ Giving very similar answers, e.g., "a new predator" and "being eaten too much".
✗ Vague answers like "they died out" or "evolution". You need to state a specific cause.
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