It was generally believed that cyanobacteria, the blue-green algae, that evolved photosynthesis appeared 2.5 billion years ago when the `Great Oxidation Event` (a spike in oxygen levels) happened.
Oxygen production by photosynthetic cyanobacteria may have initiated as early as three billion years ago, much earlier than previously thought, scientists say.
Great Oxidation Event has obvious implications for the origins and evolution of the first forms of eukaryotic life.
Day in Pics: 23rd November
Showbiz World - November 23, 2014
Los Angeles Auto Show