The activities of living things keep the levels of

oxygen and carbon dioxide in the atmosphere

balanced…

Plants remove…

…carbon dioxide from the atmosphere, and release…

…oxygen when they…

…PHOTOSYNTHESISE.

Animals, plants and microbes remove…

…oxygen from the atmosphere, and release…

…carbon dioxide when they…

…RESPIRE.

Burning fuels also removes…

oxygen from the atmosphere, and releases…

…carbon dioxide.

The Carbon Cycle

Carbon atoms on the planet Earth are constantly being recycled.

Photosynthesis converts carbon dioxide from the atmosphere into biomass.

Other chemical and biological processes release carbon dioxide from biomass into the atmosphere.

Formation of Fossil Fuels

Feeding

CO2 in atmosphere and oceans

COW

Photosynthesis

Combustion

Respiration

Death

Excretion

Decomposers

There are many ways to draw the carbon cycle…

Carbon dioxide in the air

Plants Animals

Decay

Burning of fossil fuels

Respiration by decomposers

Photosynthesis

Respiration

Respiration

Feeding

Death and Excretion

… make sure you understand the carbon cycle, and…

… do not learn it parrot fashion!

Tasks:

1. Draw out your own version of the carbon cycle.

2. What would be the effect of the following on the amount of oxygen in the atmosphere?

- an increase in the number of plants.- an increase in the burning of fossil fuels.- an increase in the number of animals.

3. How many ways can you think of increasing the amount of carbon dioxide in the atmosphere? List them.

Deforestation

• Removing plants decreases the rate of photosynthesis

• The removed trees are often burnt

• Waste plant material can be left to rot

• The cleared land is often used to farm animals like cattle, increasing the rate of respiration

• Increased industrial activity increases the use of fossil fuels

Deforestation increases the amount of carbon dioxide in the atmosphere: