BACTERIA

*Aerobic Photoautotrophs
          - rely on sunlight as a source of energy and CO2 as a source of carbon
          - primary producers
     *Cyanobacteria
          -blue-green bacteria (blue-green algae)
          - with chlorophyll a + bluish pigment
          - like plants (photosynthesis)
          - supplied O2 to premedial Earth
     *Nitrogen Fixers
          - fixation of atmospheric nitrogen
          - develop heterocysts

*Anaerobic Photoautotrophs
          - lack the key light-trapping pigment of plants, chlorophyll a anb b
          - with bacteriochlorophylls
          - purple and green bacteria
          - rely on hydrogen sulfide or H2 gas instead of H2O
          - don't produce O2

*Chemoheterotrophs
     *disease-causing bacteria
          - pathogens
     *decomposers
          - produce enzymes that breakdown organic compounds
     *fermenters

*Commercially Important Bacteria
          - used to address environmental problems
     ex: pseudomonads