Explain how the fossil record provides evidence for evolution.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Scientists have discovered a series of fossils in rock layers of different ages. The oldest fossils show simpler organisms, whilst the more recent fossils show organisms with increasingly complex characteristics.
Model answer (4 marks)
1. Fossils are the remains or impressions of dead organisms that are preserved in rock layers that are millions of years old.
2. The fossil record shows that organisms have changed over time, with older fossils being simpler and newer fossils more complex.
3. Natural selection acts on variation, favouring advantageous alleles so that they are passed on to offspring over many generations.
4. This gradual change in inherited characteristics, recorded in the fossil record, supports the theory of evolution and can lead to the formation of new species.
2. The fossil record shows that organisms have changed over time, with older fossils being simpler and newer fossils more complex.
3. Natural selection acts on variation, favouring advantageous alleles so that they are passed on to offspring over many generations.
4. This gradual change in inherited characteristics, recorded in the fossil record, supports the theory of evolution and can lead to the formation of new species.
Examiner tips
- Use the exact wording from the mark scheme (e.g., "fossils are the remains or impressions…"),
- Show the sequence of change from simple to complex fossils,
- Explain natural selection as the mechanism driving the change,
- Link the gradual change to the formation of new species.
Mark scheme (4 marks)
- Fossils are the remains or impressions of dead organisms found in rocks that are millions of years old
- Fossils show that organisms have changed / inherited characteristics have changed over time
- Natural selection acts on variation so that advantageous alleles are passed to offspring over many generations
- This gradual change in inherited characteristics over time shown by the fossil record supports evolution / may result in the formation of a new species
Key terms in this question
Related
- All WJEC GCSE Biology (Wales) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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