Some farmers keep pigs indoors in temperature-controlled buildings. Other farmers keep pigs outdoors in open fields.
The table below shows the energy inputs and energy outputs for keeping pigs in both systems:
| Energy in kJ/m2/year\text{kJ/m}^2/\text{year}kJ/m2/year | Indoors | Outdoors |
|---|---|---|
| Input as feed | 15,00015,00015,000 | 8,8008,8008,800 |
| Input as electricity and heating | 5,0005,0005,000 | 200200200 |
| Output as meat | 150150150 | 181818 |
Calculate the total energy input for keeping pigs outdoors. Use data from the table.
The total energy input for keeping pigs indoors is 20,000 kJ/m2/year20,000\text{ kJ/m}^2/\text{year}20,000 kJ/m2/year. Calculate the percentage efficiency of keeping pigs indoors.
Use the equation:
percentage efficiency=energy outputtotal energy input×100 \text{percentage efficiency} = \frac{\text{energy output}}{\text{total energy input}} \times 100 percentage efficiency=total energy inputenergy output×10061 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.