This is a schematic image of the "living fossil " Cyanophora paradoxa that is a member of the algal phylum Glaucophyta. Atmospheric oxygen really took off on our planet about 2.4 billion years ago during the Great Oxygenation Event. At this key juncture of our planet's evolution, species had either to learn to cope with this poison that was produced by photosynthesizing cyanobacteria or they went extinct. It now seems strange to think that the gas that sustains much of modern life had such a distasteful beginning.

Johns Hopkins and National Taiwan University researchers have discovered more details about how an energy sensing "thermostat" protein determines whether cells will store or use their energy reserves.