PDS APES 8th Period 2009-10

• They form the building blocks of life ( 4 macromolecules)
• Can be limiting factors if too little or too much is present

Limiting factor- (an abiotic factor that prevents growth or life of a species

Major Cycles

1)    Carbon - CHO “every living thing has CHO in it”

• Reservoirs – 1) Sedimentary Rock – 2) Oceans – 3) Fossil Fuels
• Key equations – Photo synthesis ( takes CO2 from atmosphere)

-Respiration (puts CO2 into atmosphere)

-Burning Coal, Natural Gas or Gasoline (puts CO2 into atmosphere)

-Carbonic Acid (takes CO2 out of atmosphere)

• Anthropogenic impacts (human)

-       Burning CO2 increases atmosphere

-       Deforestation (trees are a reservoir)

1)    Nitrogen – Critical for Amino Acids and Nucleic Acids. Also Nitrate (NO3)

critical for plants.

• Reservoirs – 1) Atmosphere (78% N2 “N2 is unusable to living creatures”) – 2) Oceans – 3) Soil Matter
• Key Equations – 3 Nitrogen Equations (Nitrogen Fixations, Nitrification,

Denitrification)

-Nitrogen Fixation by lightning

-Burning Fossil Fuels (Oil, Coal, Gasoline)

• Anthropogenic Impact

-Harbor-Bosh (Artificial Fertilizers)

-Burning Fossil Fuels (HNO3- Acid Rain)

-Run off from Fertilizers

N Cycle from http://www.fossweb.com/resources/pictures/16327852.gif