# A population of bacteria is introduced to a nutrient-rich culture medium. Initially the population grows slowly, then increases very rapidly, before eventually levelling off. Explain why the population growth eventually levels off and remains relatively stable.

> Cambridge International IGCSE Biology (0610) — 19.4 Populations · Explain · 4 marks

## Mark scheme (4 marks)

1. Resources (e.g. food/nutrients) become limited as population size increases
2. Increased competition leads to a higher death rate
3. Birth rate falls or equals death rate
4. Population stabilises at the carrying capacity of the environment

## Key terms

- [population](https://www.gradenine.co.uk/glossary/population)

## Related

- [Revision notes for Cambridge International IGCSE Biology (0610)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/a-population-of-bacteria-is-introduced-9b6c6c25) · Published by Druglandscape Ltd.