A researcher kept two groups of 20 young mice, which are mammals, at different air temperatures for 14 days. The researcher measured the dry biomass of food eaten, the dry mass of faeces produced and the increase in the dry biomass of the mice.
Assume that food biomass not present in the faeces was absorbed.
| Air temperature in °C | Dry biomass of food eaten in g | Dry mass of faeces in g | Increase in dry biomass of mice in g |
|---|---|---|---|
| 25 | 480 | 120 | 90 |
| 10 | 480 | 120 | 36 |
Calculate the difference between the percentages of absorbed biomass used to make new tissue at the two temperatures.
A third group is kept at 5 °C for 14 days. The dry biomass of food eaten and the dry mass of faeces produced are the same as for each group in the table.
Predict how the increase in dry biomass of the third group will compare with the increase at 10 °C.
Explain your prediction using the results of the investigation.
103 exam-style questions on AQA GCSE Biology 7.4 Trophic levels in an ecosystem, covering 7.4.1 Trophic levels, 7.4.2 Pyramids of biomass, and 7.4.3 Transfer of biomass. Each one has a worked solution and a mark scheme showing where the marks go.