AQA GCSE Biology Revision
What Is Variation in Biology?
Understand what variation means, why individuals differ, and how to use the definition in exam answers.
Exam answer
The short version
Variation means the differences in characteristics between individuals in a population. These differences can be caused by genes, the environment, or a combination of both.
Before the definition
Individuals in a population are not identical
Members of the same species can look or behave differently. Those differences are called variation, and they are important for inheritance, evolution and natural selection.
Examples of variation
Examples include height, mass, eye colour, blood group, leaf size, disease resistance and behaviour. Some examples are controlled mainly by genes, while others are strongly affected by the environment.
Genetic and environmental causes
Genetic variation comes from differences in genes inherited from parents. Environmental variation comes from surroundings and lifestyle, such as diet, climate or training. Many characteristics are affected by both.
Common exam trap
Do not define variation as evolution. Variation is the difference between individuals. Natural selection can act on variation over time, but the definition itself is about differences in characteristics.
How to answer it
Use the full definition
- 1Say that variation means differences.
- 2Specify differences in characteristics.
- 3Refer to individuals in a population.
- 4Add genetic, environmental or combined causes when the question asks why variation happens.
Key terms
Words to use in your answer
population
variation
Exam focus
This definition often starts longer answers about inheritance or evolution. A precise definition helps you avoid mixing up variation with natural selection.
Quick check
Can you answer these?
- What does variation mean?
- What is one genetic example of variation?
- What is one environmental example of variation?
- How can variation link to natural selection?
Practise this topic
Choose the next thing to do
More AQA GCSE Biology