Cycles in Nature continued
Precipitation is rain, snow, sleet or hail
Under certain conditions, decaying
When plants and animals die or give off waste,
that falls from clouds onto the earth’s
organisms form fossil fuels. Humans
decomposers convert the stored nitrogen back
surface
burn fossil fuel to produce power.
Run-off is water that flows across land
During combustion, fossil fuels are
and collects in rivers and streams and
converted to carbon dioxide and water.
eventually returns into the ocean.
Infiltration is the movement of water into
the ground due to the pull of gravity.
Percolation is the downward movement of
water through pores and other spaces in
soil due to gravity.
The CO2 is returned to the atmosphere.
The CO2 in the atmosphere can then be
passed through the cycle again.
to ammonia.
Nitrifying bacteria convert the ammonia to
nitrates. Another type of bacteria in soil called
denitrifying
bacteria convert the nitrate
to Nitrogen Gas.
Cycles in Nature Notes
Water Cycle
The continuous movement of water from
the ocean to the atmosphere to the land
Carbon Cycle
Nitrogen Cycle
Carbon moves from the atmosphere into
Nitrogen is very important to living things.
living things through photosynthesis.
During photosynthesis plants, algae, and
and back to the ocean is called the water
some bacteria use carbon dioxide to make
cycle.
sugar.
About 79% of the atmosphere is made up of
nitrogen gas. However most organism cannot
use nitrogen gas directly.
Certain bacteria in soil and in some plant roots
are able to convert the nitrogen gas to
Evaporation occurs when liquid water
During respiration organisms break down
from the earth’s surface and from living
sugar molecules to release energy. Carbon
organisms changes into water vapor.
dioxide and water are released as by
Other bacteria in soil called nitrifying bacteria
products.
convert the ammonia to another type of
Condensation occurs when water vapor
cools and changes into liquid water
When organisms decompose some of the
droplets that form clouds in the
carbon is returned to atmosphere
atmosphere.
ammonia.
nitrogen compound called nitrates. Plants
absorb some of the ammonia and nitrates.
Most animals get the nitrogen they need by
eating plants.