The Carbon Cycle

• The carbon cycle starts with carbon dioxide in the atmosphere.
• The only way that carbon can enter the carbon cycle is by photosynthesis
• Carbon dioxide returns to the atmosphere via aerobic respiration
• 1. Carbon dioxide in the atmosphere
  2. Plants and algae take in carbon dioxide in photosynthesis
  3. The carbon is used to make carbohydrates, fats, and proteins, which make up the cells of plants and algae
  4. Plants and algae respire
  5. Some of the carbon is released back into the atmosphere as carbon dioxide
  6. Plants and algae can be eaten by animals
  7. Those animals can be eaten by other animals
  8. At this point, the carbon that was part of the plants becomes part of the carbohydrates, fats, and proteins in the cells of animals
  9. Animals respire and some of the carbon dioxide goes back into the atmosphere
• The carbon cycle - decay:

  • Animals produce waste products and remains when they die
  • These products are then broken down by decomposing microorganisms (bacteria and fungi)
  • When the decomposers carry out respiration, the carbon dioxide goes back into the atmosphere
• Decomposers are important as they cycle materials through an ecosystem
• Decomposers also release mineral ions into the soil
• Under certain conditions, decomposers cannot function effectively (lack of oxygen)

  If this happens, then the carbon in the dead remains can slowly be converted to fossil fuels
• Fossil fuels --> Combustion --> carbon in the atmosphere