Notes: Cycles of Nature: Thursday 31507

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Notes Cycles of Nature Thursday 3/15/07
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An average H2O molecule takes 7 days for it to
cycle through
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Evaporation

• Heat energy from the sun causes water in puddles,
  streams, rivers, seas or lakes to change from a
  liquid to a water vapor.
• The vapor rises into the air and collects in
  clouds.  
• ENDOTHERMIC PROCESS (energy is absorbed requires
  energy)
• This is called evaporation.

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Condensation

• H2O vapor collects in clouds. As the clouds cool
  the water vapor condenses into H2O drops.
• EXOTHERMIC PROCESS (energy is released gives off
  energy)
• These drops fall to the earth as rain, snow or
  hail.
• This is called condensation.

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Precipitation

• H2O falls to the earth from clouds. Mainly as
  rain, but sometimes as snow and hail.
• This is called precipitation.

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Transpiration

• Transpiration is the process by which plants lose
  H2O out of their leaves. 
• Transpiration gives evaporation a bit of a hand
  in getting the H2O vapor back up into the air.

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The H2O Molecule is polar
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Photosynthesis
Cellular Respiration
Decomposition
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Carbon exists in the nonliving environment as
1. carbon dioxide in the atmosphere
2. carbonate rocks like limestone
3. deposits of coal, petroleum, and natural gas
4. dead organic matter
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Carbon enters the biotic world through the
action of autotrophs
photoautotrophs, like plants and algae, use the
energy of light to convert carbon dioxide to
organic matter.
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Carbon returns to the atmosphere by
respiration burning decay
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• Converts atmospheric nitrogen (N2) into a form
  living things can use

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4 processes participate in the cycle of nitrogen
through the biosphere nitrogen fixation
decay nitrification
denitrification
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Nitrogen Fixation
Break the nitrogen molecule apart so it can
combine with other atoms
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Nitrogen Fixation
Nodules on plant roots
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Decay
Break nitrogen compounds into ammonia
(NH3)
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Nitrification
Converting organic nitrogen ammonia, into
nitrates
(N2)
(NH3)
(NO3-)
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Denitrification
Reduces nitrates to nitrogen gas