- Ask pupils about the types of animals that might feed on the crops grown and establish that these are competing with humans for the crops. Ask pupils to find out what these animals,
eg fieldmouse, cabbage white butterfly, aphid, snail, slug, feed on, and emphasise that, for these animals, the food crops are part of the food web. Help pupils construct pyramids of numbers for some of the feeding relationships identified.
- Ask pupils how farmers respond to pests, and consider methods of management, including the use of pesticides. Show packaging or advertisements,
eg for insecticides, snail and slug treatment, and ask pupils to find out about what chemicals are used, how dangerous they are, and whether they are specific to one type of animal.
- Show a food web and identify a pest species that could be eliminated by a pesticide. Ask pupils to predict some effects of this on the pest species and on other populations,
eg fewer insect pests leads to a decrease in the bird population, and to relate this to pyramids of numbers.
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- identify some common animals, including pests, which feed on crops and explain that they compete with humans for these resources
- explain how the elimination of pests will affect the populations of predator animals such as birds, relating explanations to pyramids of numbers
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