Earth’s biogeologic clock

21 09 2009

earth biogeologic clock

The major lineages of pigments involved in anoxygenic photosynthesis arose before the development of oxygenic photosynthesis. The six major bacterial lineages had largely developed by the mid-Archean, around 3000 to 2800 Ma, and perhaps much earlier. The early biosphere passed through a stage during which even its photosynthetic populations depended exclusively on abiotic sources of reducing power.

Source: David J. Des Marais, “When Did Photosynthesis Emerge on Earth?” Science, 289, 1703 – 1705 (2000)




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