The Carbon and Nitrogen Cycles

1
The Carbon and Nitrogen Cycles
2
What is Carbon?

• Carbon is an element that is in all living
  things.
• Molecules containing carbon are called Organic.

3
Carbon Cycle

• The movement of carbon from the environment into
  living things and then back again is the Carbon
  Cycle.
• You already know how carbon dioxide cycles
  between photosynthesis and cellular respiration.

4
Carbon Cycle

• Carbon dioxide in the air enters into living
  things through photosynthesis.
• Oxygen and glucose produced from photosynthesis
  are then used by plants and animals for cellular
  respiration.
• Cellular respiration produces carbon dioxide to
  be released again.

5
Carbon Cycle

• Keep in mind all living things have carbon in
  them, so when they die, decomposers help return
  that carbon to the environment and soil.

6
Carbon Cycle

• Carbon in the environment is used to make coal,
  oil, and natural gas (fossil fuels).
• Fossil fuels are burned in a process called
  Combustion.
• Combustion releases carbon dioxide back into the
  air.

7
What is nitrogen?

• Nitrogen is used to build proteins and DNA.

8
Nitrogen Cycle

• The movement of nitrogen from the environment to
  living things and back again is the Nitrogen
  Cycle.
• About 78 of the Earths atmosphere is nitrogen
  gas, however most organisms cannot use nitrogen
  when its in a gas form.

9
Nitrogen Cycle

• Nitrogen fixation is when lightning or bacteria
  in the soil change nitrogen gas into a form that
  can be taken up by plant roots.

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Nitrogen Cycle

• Animals eat the plants and therefore take in
  nitrogen.
• When animals and plants die, decomposers help
  return the nitrogen to the soil.
• Other bacteria then change the nitrogen in the
  soil back into a gas to be released back into the
  air.