[Maursault]

> Life began in that alien environment, and at some point between 3.2 and 2.8 billion years ago, cyanobacteria began to use sunlight to split hydrogen from water, discarding oxygen as waste.

David Attenborough brilliantly explains the beginning of life and the role of cyanobacteria in the first episode of Life on Earth (1979), "The Infinite Variety,"[1] (in less than 20 minutes; doesn't need to be that long, but I wanted to catch him riding the mule, sooooo... strap in and enjoy).

[0] https://www.dailymotion.com/video/x2i43qc?start=673