quality:correction, stylistic:tone, information:classification, information:filtering
Effects on life

The Great Oxygenation Event had the first major effect on the course of evolution. Due to the rapid buildup of oxygen in the atmosphere, the mostly anaerobic microbial biosphere that existed during the Archean eon was devastated, and only the aerobes that had antioxidant capabilities to neutralize oxygen thrived out in the open. This then led to symbiosis of anaerobic and aerobic organisms, who metabolically complemented each other, and eventually led to endosymbiosis and the evolution of eukaryotes during the Proterozoic eon, who were now actually reliant on aerobic respiration to survive. After the Huronian glaciation came to an end, the Earth entered a long period of geological and climatic stability known as the Boring Billion. However, this long period was noticeably euxinic, meaning oxygen was scarce and the ocean and atmosphere were significantly sulfidic, and that evolution then was likely comparatively slow and quite conservative.