The Nitrogen Cycle

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The Nitrogen Cycle

• Major Processes
• Nitrification
• Denitrification
• Decomposition
• Assimilation

Denitrification
Nitrogen Fixation
Nitrification
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Components of the Nitrogen Cycle

• N2 (nitrogen gas)
• In the atmosphere cannot be used by plants or
  animals
• NH3 (ammonia)
• Found in soil cannot be used by plants or
  animals
• NO2 (nitrite)
• Found in soil cannot be used by plants or animals

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Components of the Nitrogen Cycle (Continued)

• NO3- (nitrate) NH4 (ammonium)
• Only compounds of nitrogen that plants can use
• Various nitrogen compounds such as amino acids
• Many different compounds that living things need
  for survival

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Processes of the Nitrogen Cycle

• Nitrification
• The process by which unusable nitrogen compounds
  are changed into compounds used by plants and
  animals.
• Ex Conversion of nitrogen gas (N2) to ammonium
  (NH4)
• Carried out by nitrogen-fixing bacteria
• Ex Conversion of nitrogen gas (N2) to nitrate
  (NO3-)
• Occurs when lightening strikes

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Processes of the Nitrogen Cycle

• Denitrification
• The process of changing complex nitrogen
  compounds into atmospheric nitrogen
• Ex Conversion of nitrate (NO3-) to nitrogen gas
  (N2)
• Carried out by denitrifying bacteria

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Processes of the Nitrogen Cycle

• Decomposition
• The process of changing dead plants animals
  into simple nitrogen compounds.
• Assimilation
• The process of changing usable nitrogen compounds
  by plants into complex plant or animal nitrogen
  compounds.

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Switch to handout on Nitrogen Cycle
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Question of the day

• What are the four stages in the nitrogen cycle?
  And in what order?
• The nitrogen cycle would not function without
  these two key organisms
• Name a legume plant and define what that means.

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Back of Nitrogen Cycle Handout

• What source of energy ultimately drives the
  nitrogen cycle? Explain.
• The Sun It gives plants the energy to
  absorb soil nitrates (NO3)- so the plant can make
  protein and grow.

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Back of Nitrogen Cycle Handout

• 2. How do animals obtain nitrogen as shown in
  Figure 3-13?
• Animals eat plant or animal protein to get
  N. They digest it and then use amino acids to
  make protein.

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Back of Nitrogen Cycle Handout

• 3. In what form does nitrogen appear in the
  air? Where does it come from?
• N2 (nitrogen gas).
• Bacteria break down plant animal protein
  and N compounds in soil.

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Back of Carbon Cycle Handout

• 4. What form on nitrogen are most plants able
  to absorb? How does it get into that form?
• Nitrates (NO3)
• Special bacteria (nitrogen-fixers) are in
  little nodules on roots of certain
  plants-legumes. Ex Clover, peanuts, soybeans,
  alfalfa
• You can cross out 5 on your sheet ?

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Review Video

• https//www.youtube.com/watch?vLbBgPekjiyc

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Mineral/Rock cycle

• Living organisms need other minerals, like Ca,
  Mg, Fe, etc.
• They come from the releasing of minerals from
  rocks.
• So, how does the rock cycle work and how are
  minerals incorporated in the environment?

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(No Transcript)
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The mineral cycle
See page 33 of textbook
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What to study

• HW from textbook and any textbook readings
• Class notes
• Food web diagrams, concept map, N,C and H20 cycle
  diagrams
• Vocabulary
• Case Study Reintroduction of Wolves