1. Cycling of Materials in
the Ecosystem

2. Carbon Dioxide-Oxygen Cycle
• Plants photosynthesize
Plants use carbon
dioxide for the process of
photosynthesis, together
with water. Using the
energy of the Sun, plants
make sugars and oxygen
molecules. All of the nonphotosynthetic creatures
on the planet use the
oxygen. Every creature on
the planet uses the sugars
and starches created by
plants.

3. Carbon Dioxide-Oxygen Cycle
• Respiration
Animals take in
oxygen from the
atmosphere and give off
carbon dioxide during
respiration. This occurs day
and night.
Plants, however, give off
oxygen and take in carbon
dioxide when they
photosynthesize during the
day. At night, when plants
are in darkness and cannot
photosynthesize, they
“breathe” just like animals.
They take in oxygen and

4. W
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• Water in the atmosphere is found in clouds
and water vapor.
• When weather is created one of the most
common results is precipitation.
• It could be rain, snow, drizzle, fog, dew, or
hail. Whatever path, the water comes out of
the atmosphere and makes it to the surface.

5. W
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Snow can melt and become rivers that flow
into the oceans. Water can collect
underground (groundwater). Water can
collect in the oceans.
• Water moves from the ground or oceans
into the atmosphere through a process
called evaporation.
•

6. Nitrogen Cycle

7. How do Human Activities
Affect the Ecosystem?
“Do you know why people die? Its because
of your trash...”
Monoculture

8. How do Human Activities
Affect the Ecosystem?
“Do you know why people die? Its because
of your trash...”
Herbicides and
Insecticides

9. How do Human Activities
Affect the Ecosystem?
“Do you know why people die? Its because
of your trash...”
Chemical
Fertilizers