CAIE A Level Biology 9700 · Classification, biodiversity and conservation
A student investigates plant biodiversity in a large meadow. They place 20 quadrats (0.5 m × 0.5 m) only in the area closest to the footpath, because it is easier to access. They record the number of individuals of each plant species in each quadrat and calculate Simpson's index of diversity (D).
Explain why the student's sampling method is inadequate and why random sampling is essential for estimating biodiversity.
6 marks, so the mark scheme is looking for about 6 separate creditworthy points. Making the same point twice in different words earns it once.
Explain means: Give the reasons or the mechanism: why or how something happens. Link each point to the next with because, so or which means. A list of facts with no links usually loses the reasoning marks.
Written by Markquill to follow the Cambridge International syllabus. Markquill is independent and is not affiliated with or endorsed by Cambridge International.