Photosythetic organisms are the producers of biomass for life on Earth
Food chains - start with a producer which sythesises new molecules
Producers are eaten by primary consumers - secondary consumers - tertiary consumers
In a stable community, numbers of predators and prey rise and fall in cycles
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Materials cycling
Material in the living world is recycled to provide building blocks for future organisms
Decay of dead animals and plants by microorganisms returns carbon dioxide and mineral ions to the soil
Carbon dioxide in the atmosphere is used by plants in photosynthesis
The water cycle provides fresh water for plants and animals on land before draining into the seas. Water is continuously evaporated, condensed, and precipitated
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The carbon cycle
The carbon cycle returns carbon from organisms to the atmosphere as carbon dioxide to be used by plants in photosynthesis
The decay of dead plants and animals by microorganisms returns carbon to the atmosphere as carbon dioxide
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Rates of decomposition
Factors that affect the rate of decay of organic matter are - temperature, oxygen availability, moisture levels
Gardeners and farmers try to provide optimum conditions for the rapid decay of waste organic matter. the compost produced is used as a natural fertiliser
Anaerobic decay produces methane gas. biogas generators can be used to produce methane gas as a fuel
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