1. INVESTIGATING THE CARBON CYCLE
Think about the following:
What biological molecules contain carbon?
What process releases carbon dioxide from living things?
What process takes in carbon dioxide and converts it into glucose?
How does carbon pass from one organism to the next in a food chain?
Bacteria, fungi and other decomposers feed on dead organisms and waste material such as faeces. How would these organisms return carbon into the atmosphere?
Under the right conditions, carbon in dead organisms is locked up in coal, oil, gas and other fossil fuels. High pressure and incomplete decay lead to the production of such fossil fuels over thousands of years. How is the carbon in these materials being returned to the atmosphere?

2. Now complete the diagram on the next slide, completing text boxes and using these words:
Respiration, photosynthesis, combustion, carbon dioxide, decomposition, consumption/eaten by
Finally, make a drawing of this simplified carbon cycle onto a Cornell sheet, for your file.

4. EXTENSION What role does limestone play in the carbon cycle?
Can you find out how much carbon is stored in each of the reservoirs in which it is found (for example, the ocean, fossil fuels, the atmosphere, sedimentary rock, the Earth's mantle)?
How are human activities affecting the carbon cycle?