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Roles in Evolution
The tiny respirations of these organisms over millions of years largely created Earth's oxygen-rich atmosphere, paving the way for more complex living things.
— Bill Bryson
P.S. This is Archean Eon, the second of four geologic eons of Earth's history, from 4 to 2.5 billion years ago, when the cyanobacteria first appear with others anaerobic bacteria and archaea
During Archean Eon


Anaerobes domination(phototropic)
High Temperature-High concentration of Greenhouse gases

Atmopshere composition :Abundant CO2, methane, H2O, and little oxygen (frequent volcanoic eruptions)


Absence of currently existing ozone layer
Frequent volcanic and cometic activities


Cyanobacteria's unique ability of producing oxygen using sunlight through the process of photosynthesis induce the Oxygen Catastrophe
The Great Oxidation

Impact page
The Impacts of The Great Oxidation
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