Ecologists compare changes in the distribution of four species. Which observation shows a change in distribution caused by a geographic change?
A river changes course, and a population is found only on one side of the new channel
Air pollution increases, and a sensitive population disappears from sites close to a town
Each winter, a population moves from exposed ground into sheltered parts of the same valley
The soil becomes drier, and a moisture-dependent population retreats from part of a grassland
83 exam-style questions on AQA GCSE Biology 7.2 Organisation of an ecosystem, covering 7.2.1 Levels of organisation, 7.2.2 How materials are cycled, 7.2.3 Decomposition, and 7.2.4 Impact of environmental change (HT only). Each one has a worked solution and a mark scheme showing where the marks go.