Substantial environment altering event in occurring in the vicinity of 2.7 to 2.3 billion years ago.

The oxygen revolution, which particularly involved the release of molecular oxygen into and the , is a direction consequence of the invention by organisms of "modern", photosynthesis by cyanobacteria.

We can date the timing of this event in terms of the appearance of in the , particularly the appearance of substantial amounts of .

The result of the oxygen revolution was both a substantial reorganization of what could live where (particularly, could no longer live "everywhere") along with a opportunity for the appearance, in much larger numbers of locations/niches, of organisms which could generate ATP via cellular respiration.