IGCSE Biology glossary
Transect
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
A line placed across a habitat along which organisms are sampled at regular intervals, usually with quadrats. A transect is used to study how the distribution of organisms changes across an environmental gradient, such as from a shoreline to inland or from light to shade.
What to include in an exam answer
Use a transect when investigating how species distribution changes across an area (not random sampling). A belt transect places quadrats at regular intervals along a line; a line transect records organisms touching the line.
Example in context
Explain when a transect would be more suitable than random sampling (2 marks): A transect is more suitable when investigating how the distribution of organisms changes across a habitat in response to an environmental gradient, such as changes in light intensity from a forest edge to the interior.
Related syllabus topic
Organisms & their environment