Questions and Answers

State the roles of microorganisms in the nitrogen cycle, limited to: decomposition, nitrification, nitrogen fixation and denitrification (generic names of individual bacteria, e.g. Rhizobium, are not required)

Describe the nitrogen cycle with reference to: • decomposition of plant and animal protein to ammonium ions • nitrification • nitrogen fixation by lightning and bacteria • absorption of nitrate ions by plants • production of amino acids and proteins • feeding and digestion of proteins • deamination • denitrification

Describe the carbon cycle, limited to: photosynthesis, respiration, feeding, decomposition, formation of fossil fuels and combustion

Explain, in terms of energy loss, why food chains usually have fewer than five trophic levels

Explain why the transfer of energy from one trophic level to another is often not efficient

Discuss the advantages of using a pyramid of energy rather than pyramids of numbers or biomass to represent a food chain

Draw, describe and interpret pyramids of energy

Identify the following as the trophic levels in food webs, food chains and ecological pyramids: producers, primary consumers, secondary consumers, tertiary consumers and quaternary consumers

Describe a trophic level as the position of an organism in a food chain, food web or ecological pyramid

Discuss the advantages of using a pyramid of biomass rather than a pyramid of numbers to represent a food chain