The Process of Decay (WJEC GCSE Biology)

• Waste products and the bodies of dead organisms are broken down by decomposers such as bacteria and fungi
  • The process by which dead and waste material is broken down is known as decay
• Decomposers digest the molecules in dead or waste material; the results of this process include:
  • Products of digestion can be used by the microorganisms for growth and other life processes such as reproduction and respiration
    • Respiration in microorganisms releases carbon dioxide which enters the atmosphere
  • Products that are not needed by the microorganisms, or that are produced in excess, re-enter the surrounding environment where they are available to other organisms once again
    • E.g. nitrogen from the breakdown of waste proteins can be converted into nitrates and taken up by plants
• The activity of decomposers depends on environmental factors such as temperature, oxygen concentration and water availability; if conditions are not right then decay may not take place
  • When decay does not occur carbon compounds may remain locked up in dead tissues for extended time periods
  • This can result in the formation of coal, oil and natural gas; these are fossil fuels that contain stored chemical energy in the form of carbon compounds

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Decomposers, such as fungi and bacteria, break down dead and waste material