Carbon cycle

• Leaves that fall off trees are broken down by bacteria and fungi, and the nutrients are recycled back into the ecosystem
• There is a constant recycling of chemicals on the planet
• The carbon atoms in your body have probably been part of someone else before
• When organisms die and are buried, the carbon atoms go back into the soil and get broken down by bacteria and fungi, then may end up going into a plant, and then an animal may have eaten that plant, and then you may have eaten that animal
• The same carbon atoms are just being cycled around the planet and being constantly reused
• Microorganisms such as bacteria


  • They play a key role in breaking down complex organic molecules and returning the elements to the environment so they can be reused again
  • Elements can move between the living and the non-living world
• Carbon cycle


  1. Carbon dioxide in the air

  2. Photosynthesis (carbon dioxide + water -> glucose + oxygen)

  3. Respiration (organisms return carbon dioxide to the atmosphere)

  4. Decomposition (carbon in organisms' bodies and excretion returned to soil)

  5. Fossilization (some organisms get fossilized into coal and oil)

  6. Combustion (fossil fuels release carbon dioxide back to the atmosphere)
• The carbon that is in us will go on to build other living things in years to come, and we are built of carbon that has already been living things before us