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Material Cycles
Material Cycles
• On your own…
– What is a cycle?
– Make a list of things in an ecosystem need to
be cycled and reused in order for ecosystem
to be stable.
Material Cycles
• Although an ecosystems needs
continuous supply of energy from outside
itself…
– Its raw materials are continuously cycled and
reused.
• Carbon-Hydrogen-Oxygen Cycle
• Water Cycle
• Nitrogen Cycle
Carbon- Hydrogen- Oxygen Cycle
Carbon- Hydrogen- Oxygen Cycle
• Carbon (C), Hydrogen (H) and Oxygen (O)
are cycled by the process of:
– Respiration
• The C and H found in organic compounds
(glucose) react with O to produce CO2 and H2O
– Photosynthesis
• H2O is broken down to H and O, Oxygen gets
released and H is combined with CO2 to make the
organic compound (glucose)
The Water Cycle
The Water Cycle
• Water on the earth’s surface enters the
atmosphere in the form of water vapor by
– Evaporation: comes from body of water
– Transpiration: comes from plants
• It returns to the surface by
– Condensation: clouds
– Precipitation: rain, snow, hail , sleet
The Nitrogen Cycle
• What do organisms need Nitrogen (N) for?
– TO MAKE PROTEINS!!!!
• Decomposers play an important role in the
nitrogen cycle
– Decomposers and other soil bacteria are
essential in converting the nitrogenous waste
(ex: Urine) into a form of nitrogen useable by
plants as a fertilizer
The Nitrogen Cycle
• Nitrogen in the atmosphere is absorbed by
NITROGEN FIXING BACTERIA and convert it
into nitrate salts
– This nitrogen fixing bacteria live in small nodes on the
roots of leguminous plants
• Plants in the area take up these nitrates and use
them to make proteins
• As plants are consumed by herbivores the protein
from the plant will be convert to animal protein
within the cell
The Nitrogen Cycle
• When these plants or animals die their
bodies are consumed by Bacteria of
Decay.
– Which releases AMMONIA (NH4)
• This can be absorbed by denitrifying
bacteria which will break it down and
convert it back in to N2 (gas) for the
atmosphere