Evolution (OCR GCSE Biology A, Combined (Gateway Science Suite)): Revision Notes
📚 Revision Notes
6.2.2 Evolution
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Evolution is a change in the inherited characteristics of a population over time through a process of natural selection which may result in the formation of a new species.
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Theory of Evolution: All species have evolved from simple life forms that first developed more than three billion years ago.
Evolution occurs because of natural selection.
- Mutations occur which provide variation between organisms.
- If a mutation provides a survival advantage the organism is more likely to survive to breeding age.
- The mutation will then be passed onto offspring.
- Over many generations, the frequency of the mutation will increase within the population.
This may cause one population of a species to become so different that they can no longer interbreed to produce fertile offspring. This means they have become a new species. This is called speciation.