1.1. A farmer was interested in improving the stability of their agricultural ecosystem.

State the meaning of the term ecosystem.

1.2. The farmer investigated the effect of different types of animal grazing on beetles in their fields. They measured the number of different beetle species and the total number of beetles in cow grazed (1), donkey grazed (2) and sheep grazed (3) fields.

Their results are shown in Fig. 1 below. Note that the error bars represent standard deviation.

Fig. 1

Calculate the percentage difference in number of species of beetle between a cow-grazed field and a donkey-grazed field. Give your answer to one decimal place.

1.3. The farmer considered the results in Fig. 1 and concluded that the type of grazing had little effect on beetles, and therefore on the stability of the agricultural ecosystem.

Discuss the farmer's conclusion.

1.4. Suggest three considerations that the farmer should have taken into account when planning the investigation to ensure valid results.