Prokaryote evolution study published

A genomic timescale of prokaryote evolution: insights into the origin of methanogenesis, phototrophy, and the colonization of land has just been published in BMC Evolutionary Biology.

The conclusion is that methane was generated by early prokaryotes, causing the land surfaces to warm sufficiently for terrestrial bacteria to colonise them. In short, oxygenation of our atmosphere was caused by terrestrial adaptations.