An ecologist estimates the total population of beetles in a study area using the capture-recapture method.
On Monday, she captures a sample of 505050 beetles, marks them with a non-toxic paint, and releases them.
On Tuesday, she captures a second sample of 404040 beetles and finds that 888 of them are marked.
Estimate the total beetle population in the study area.
67 exam-style questions on OCR GCSE Biology 4.1 Ecosystems, covering 4.1.1 Cycling of materials in ecosystems, 4.1.2 Microorganisms in cycling materials, 4.1.3 The carbon and water cycles, 4.1.4 Factors affecting decomposition, 4.1.5 Levels of organisation in an ecosystem, 4.1.6 Abiotic and biotic factors affecting communities, 4.1.7 Interdependence and competition, 4.1.8 Trophic levels, 4.1.9 Pyramids of biomass, and 4.1.10 Efficiency of biomass transfers. Each one has a worked solution and a mark scheme showing where the marks go.