Re: Country roads revisited - life is old there..OLDER than the mountains...

On 7/29/2024 5:28 AM, burkhard wrote:

according to this new, but heavily disputed research on how old
complex life on Earth is
 https://www.bbc.co.uk/news/articles/c3geyvpxpeyo
 

https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.16249
This paper indicates that aerobic photosynthesis may have evolved a billion years before the great Oxidation event 2.3 billion years ago (could have evolved over 3 billion years ago).  It looks like anoxygenic photosynthesis evolved first and the Oxigenic photosystem cores evolved from anoxygenic cores.  A recent paper that I put up indicated that cyanobacteria evolved nitrogen fixation before they evolved oxygenic photosynthesis.  This means that it was an uphill climb for oxigenic photosynthesis when vital systems needed anaerobic conditions to function.  Chemotrophes are anaerobic, so oxygen was poison to lifeforms when oxygenic photosynthesis evolved, even to the cyanobacteria that evolved the system.  Anoxygenic photosynthetic bacteria still exist in oxygen poor environments.
The fact that all life was adapted to anaerobic conditions could have delayed the great oxidation event for a billion years.  No one wanted oxydative phototrophes for neighbors, not even the oxidative phototrophes that fixed nitrogen that had to deal with self inflicted oxygen generation.
Ron Okimoto