Unit 2 Community Ecology Ecosystems and the Biosphere

3-4 Ecosystem Recycling
• Water cycle- Cells contain 70-90% water
for chemical reactions to occur.
• Carbon cycle- part of organic materials
(glucose) that living things use for energy
• Nitrogen cycle- Nitrogen is used for the
building of proteins (amino acids) and
Nucleic acids.
Water cycle
Carbon Cycle
Nitrogen cycle
• Nitrogen fixation=N2 into Nitrates (bacteria do
this for plants to use)
• Ammonification=decomposers break down the
Nitrogen in dead material into ammonia.
• Nitrification=Bacteria take up ammonia and
oxidize into nitrates and nitrites (plants use this
for amino acids)
• Denitrification=anaerobic bacteria break down
nitrates and release N2 back in the atmosphere.
Nitrogen Cycle