An ecologist wants to estimate the size of a population of woodlice in a small section of a woodland.
She catches a sample of woodlice, marks them with a small dot of non-toxic paint, and then releases them back into their habitat. A few days later, she captures another sample and counts how many of them are marked.
What is the name of the method she is using?
Systematic sampling
Belt transect
Capture-recapture
Random quadrat sampling
25 exam-style questions on OCR GCSE Biology 6.1 Monitoring and maintaining the environment, covering 6.1.1 Field investigation of distribution and abundance, 6.1.2 Human interactions and biodiversity, 6.1.3 Maintaining biodiversity, and 6.1.4 Environmental change and distribution of organisms. Each one has a worked solution and a mark scheme showing where the marks go.