# Ecological succession

The gradual change in species over time in an area. Primary succession starts on bare ground, such as new volcanic rock. Secondary succession follows a disturbance, such as a fire, on soil that already exists, and is faster.

Biology (university) · Part 10: Ecology and the environment · Card 8 of 9 · Last updated 2026-10-19

## Analogy

A new housing estate growing from bare plots into a mature neighbourhood.

## In practice

Lichens and mosses colonise bare rock, then grasses, shrubs and finally trees arrive.

## Practice

### Flashcards

- **How does secondary succession differ from primary?** It starts on existing soil after a disturbance, so it is faster.

### Interview questions

**Discuss the main threats to biodiversity and one strategy for conservation.**

- Habitat loss
- Invasive species, pollution, over-harvesting, climate change
- Protected areas or corridors
- Genetic diversity and stability

## Questions people ask

### What is a climax community?

A climax community is the stable, mature stage that succession tends toward, for example a forest. Ecologists now see this as less fixed than once thought, because disturbances like fires, storms and changing climate keep resetting parts of the landscape, so it is often a patchwork of stages.

### What are pioneer species?

Pioneer species are the first to colonise bare or newly disturbed ground, such as lichens, mosses and fast-growing weeds. They tolerate harsh conditions and help create soil as they die and decay. This makes it possible for other plants to arrive and take over.

## Related concepts

- [Biodiversity](https://studyvisually.com/learn/science/biology-university/biology-university-part-10/biology-university-part-10-concept-9)
- [Ecological niche](https://studyvisually.com/learn/science/biology-university/biology-university-part-10/biology-university-part-10-concept-2)
- [Symbiosis](https://studyvisually.com/learn/science/biology-university/biology-university-part-10/biology-university-part-10-concept-3)

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