Microbes Switched to Oxygen 2.72 Billion Years Ago

Scientists have known for a while that the Earth's atmosphere switched rather quickly from very little oxygen to near our current levels around 2.4 billion years ago. The development of photosynthesis is generally offered as an explanation for the change. (Here is the Story)

Two researchers from the Carnegie Institution and Penn State University have discovered evidence showing microbes adapted to living with oxygen 2.72 billion years ago, at least 300 million years before the rise of oxygen in the atmosphere. The finding is the first concrete validation of a long-held hypothesis that oxygen was being produced and consumed by that time and that the transition to an oxygenated atmosphere was long term.

This is a very interesting story regarding an important evolutionary development. Its amazing to think that all of this was occuring billions of years ago.