IGCSE Biology glossary
Continuous 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
Variation that shows a complete range of phenotypes between two extremes, with no distinct categories. Examples include height, mass and foot length. Continuous variation is typically controlled by many genes (polygenic) and influenced by the environment.
What to include in an exam answer
Continuous variation is displayed as a histogram with a normal distribution curve. Examples: height, mass, hand span. Contrast with discontinuous variation, which has distinct categories.
Example in context
Distinguish between continuous and discontinuous variation, giving one example of each (4 marks): Continuous variation shows a range of values with no distinct groups (e.g. Height). Discontinuous variation has distinct categories with no intermediates (e.g. Blood group).
Related syllabus topic
Variation & selection