An ecologist was studying a population of beetles in a woodland. She caught 80 beetles in the first sample. She marked them and released them. She caught 60 beetles in the second sample. 15 of these beetles were marked. Use this equation:
estimated population=number caught in first sample×number caught in second samplenumber in second sample that are marked \text{estimated population} = \frac{\text{number caught in first sample} \times \text{number caught in second sample}}{\text{number in second sample that are marked}} estimated population=number in second sample that are markednumber caught in first sample×number caught in second sampleWhat is the estimated population?
240
320
4800
72000
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.