Pasteur effect The transition from an anaerobic to an aerobic life-style, which occurs among certain organisms when the oxygen content of the atmosphere is 1% of that of the present day. The critical point of transition is the ‘Pasteur point’. The gradual oxygen enrichment of the Earth's atmosphere during the Precambrian passed through the Pasteur point approximately 700 Ma ago, resulting in a general transition to an aerobic life-style.

Pasteur effect The transition from an anaerobic to an aerobic lifestyle, which occurs among certain organisms when the oxygen content of the atmosphere is 1 per cent of that obtaining now. The critical point of transition is the ‘Pasteur point’. The gradual oxygen enrichment of the Earth's atmosphere during the Precambrian passed through the Pasteur point approximately 700 Ma ago, resulting in a general transition to an aerobic lifestyle.