IGCSE Biology glossary
Variation
Biology editorial review is supported by the named review panel. Reviewer participation may vary by guide. Checked against Cambridge IGCSE Biology 0610 (2026–2028); last reviewed August 2026.
Definition
Differences between individuals of the same species. Continuous variation (e.g. Height) shows a complete range and is affected by many genes and environment; discontinuous variation (e.g. Blood group) has distinct categories and is usually controlled by genes alone.
What to include in an exam answer
Classification questions give you a feature and ask which type. Decide by asking 'is there a full range or separate boxes?'. Mutation, meiosis and random fertilisation as causes of genetic variation is a recurring 3-marker.
Example in context
Classifying a feature: 'Height shows continuous variation because it has a full range of values, controlled by many genes and affected by the environment.'
Related syllabus topic
Variation & selection