# Evolution

The slow change of a species over many generations as natural selection favours helpful features.

Biology (school) · Part 06: Variation and evolution · Card 5 of 11 · Last updated 2026-10-19

## Analogy

A path worn into the grass by many feet over time.

## In practice

All the life on Earth today evolved from simple life forms that lived over three billion years ago.

## Practice

### Flashcards

- **How long does evolution take?** Many generations, usually thousands to millions of years.

### Interview questions

**Explain how natural selection can lead to evolution.**

- There is variation within a species
- Individuals with helpful features survive and breed
- They pass on the alleles for those features
- Over many generations the population changes

**What evidence supports evolution?**

- Fossils show gradual change over time
- Antibiotic-resistant bacteria evolve quickly
- Similar DNA in related species
- Extinct species found only in older rock layers

## Questions people ask

### Is evolution just a theory?

In science, a theory is a well-tested explanation backed by a large amount of evidence, not just a guess. The theory of evolution is supported by fossils, DNA comparisons, and observations like antibiotic resistance. It is one of the most strongly supported ideas in biology.

### Did humans evolve from monkeys?

No. Humans and modern monkeys share a common ancestor that lived millions of years ago. Our lines then split and each group evolved separately. Humans are more closely related to chimpanzees and other apes. Scientists support this using fossils and DNA comparisons.

## Related concepts

- [Natural selection](https://studyvisually.com/learn/science/biology-school/biology-school-part-6/biology-school-part-6-concept-3)
- [Extinction](https://studyvisually.com/learn/science/biology-school/biology-school-part-6/biology-school-part-6-concept-8)
- [Variation](https://studyvisually.com/learn/science/biology-school/biology-school-part-6/biology-school-part-6-concept-1)
- [Fossil](https://studyvisually.com/learn/science/biology-school/biology-school-part-6/biology-school-part-6-concept-7)

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