The Oxygen Revolution: Cyanobacteria “hacked” the sun to split water, releasing oxygen as a byproduct and triggering the first global environmental catastrophe and subsequent biological reset.

By evolving oxygenic photosynthesis, Cyanobacteria unlocked an infinite energy source: water and sunlight. This success flooded the atmosphere with oxygen, a toxic gas that wiped out most anaerobic life (the Great Oxidation Event) but created the high-energy environment necessary for the later evolution of complex animals and plants.