C4.2 Transfer of energy and matter

C4.2.1 Ecosystems

C4.2.2 Sunlight

C4.2.3 Flow of chemical energy through food chains

C4.2.4 Construction of food chains and food webs

C4.2.5 Supply of energy to decomposers

C4.2.6 Autotrophs

C4.2.7 Use of light as the external energy source

C4.2.8 Heterotrophs

C4.2.9 Release of energy in both autotrophs and heterotrophs

C4.2.10 Classification of organisms into trophic levels

C4.2.11 Construction of energy pyramids

C4.2.12 Reductions in energy availability at each successive stage in food chains

C4.2.13 Heat loss to the environment in both autotrophs and heterotrophs

C4.2.14 Restrictions on the number of trophic levels in ecosystems

C4.2.15 Primary production as accumulation of carbon compounds in biomass by autotrophs

C4.2.16 Secondary production as accumulation of carbon compounds in biomass by heterotrophs

C4.2.17 Constructing carbon cycle diagrams

C4.2.18 Ecosystems as carbon sinks and carbon sources

C4.2.19 Release of carbon dioxide into the atmosphere during combustion

C4.2.20 Analysis of the Keeling Curve in terms of photosynthesis, respiration and combustion

C4.2.21 Dependence of aerobic respiration on atmospheric oxygen produced by photosynthesis

C4.2.22 Recycling of all chemical elements required by living organisms in ecosystems