1. Energy transfer between trophic levels

2. How much of the Sun’s energy is actually converted to organic matter? Why?

3. 1-3%1-3% 90+% reflected back into space by dust and clouds90+% reflected back into space by dust and clouds Some wavelengths of light cannot be absorbed by plantsSome wavelengths of light cannot be absorbed by plants Light might not fall on a chlorophyll molecule.Light might not fall on a chlorophyll molecule. Other limiting factors restrict the rate of photosynthesis such as CO2 concentration and temperature.Other limiting factors restrict the rate of photosynthesis such as CO2 concentration and temperature.

4. What are gross and net production?

5. Gross production is the total amount of energy converted into organic matter.Gross production is the total amount of energy converted into organic matter. 20-50% used in respiration.20-50% used in respiration. Net production is the energy remaining after respiration.Net production is the energy remaining after respiration. Net Production = Gross Production – Respiratory LossesNet Production = Gross Production – Respiratory Losses

6. Why is the percentage of energy transfer between trophic levels so low?

7. Not all the organism is consumed.Not all the organism is consumed. Not all parts are digestible so they are excreted.Not all parts are digestible so they are excreted. Some energy is lost in excretory substances.Some energy is lost in excretory substances. Considerable heat is lost by respiration.Considerable heat is lost by respiration.

8. What can be explained by the inefficiency of energy transfer between trophic levels?

9. The number of trophic levels being limited to 4 or 5, as there is insufficient energy to support a breeding population at this stage.The number of trophic levels being limited to 4 or 5, as there is insufficient energy to support a breeding population at this stage. Biomass decreases at higher trophic levels.Biomass decreases at higher trophic levels. Less energy is stored at each trophic level.Less energy is stored at each trophic level.

10. Calculating efficiency of energy transfers (kJ/m²/year) (Energy available after transfer ÷Energy available before transfer) x 100 (Energy available after transfer ÷ Energy available before transfer) x 100

14. Glossary Trophic level – the position of an organism in a food chainTrophic level – the position of an organism in a food chain Gross Production – total amount of the Sun’s energy converted to organic matterGross Production – total amount of the Sun’s energy converted to organic matter Net Production – organic matter available after respiratory/excretory lossesNet Production – organic matter available after respiratory/excretory losses Biomass – total mass of living material in a specific area at a given time.Biomass – total mass of living material in a specific area at a given time. Energy efficiency – the percentage of energy used after the transfer for growth and other processes rather than wasted.Energy efficiency – the percentage of energy used after the transfer for growth and other processes rather than wasted.