2.2
Cycles of Matter
Water cycle
• A continuous process by which water moves
from Earth’s surface to the atmosphere and
back.
Evaporation
• Process by which
molecules of liquid
water absorb energy
and change into a gas.
Condensation
• The process by which a
gas changes to a liquid.
Precipitation
• As more water
condenses, the drops of
water in a cloud grow
large and fall to the
ground as rain.
Water Cycle
The Carbon and Oxygen cycles
• Producers , consumers and decomposers each
play a role in the carbon cycle and the oxygen
cycle.
Carbon Cycle
STEP 1
• Carbon dioxide is absorbed by producers to
make sugars during photosynthesis. These producers then
put off oxygen.
Carbon Cycle
STEP 2
• Consumers feed on the plants. Thus passing the carbon
compounds along the food chain. Most of the carbon these
consumers consume however is exhaled as carbon dioxide.
This is through the process of respiration. The producers and
consumers then eventually die.
Carbon Cycle
STEP 3
• The dead producers and consumers are eaten
by decomposers. The carbon that was in their bodies is then
returned to the atmosphere as carbon dioxide.
Oxygen Cycle
• Producers release oxygen as a result of
photosynthesis.
• Most organisms take in oxygen from the air
and use it to live.
Human impact
• Humans affect the levels of carbon and oxygen
in the atmosphere.
• When we burn fuels like wood and gasoline
carbon dioxide is released into the air.
The Carbon and Oxygen cycles
Nitrogen Cycle
• Nitrogen moves from the air to the soil, into
living things and back into the air.
Nitrogen Fixation
• The process of changing
free nitrogen into a
usable form of nitrogen.
• Nodules
• Legumes
–
–
–
–
–
Clover
Beans
Peas
Alfalfa
Peanuts
Nitrogen Cycle