joe{at}removethispart.gs.washington.edu (Joe Felsenstein) wrote in
news:cj9cfv$6ve$1{at}darwin.ediacara.org: 

> In article ,
> Brett Aubrey   wrote:
>>My notes suggest that the earliest photosynthesis was around ~3.1 BYA,
>>which concurrently began to create an oxidized atmosphere.  This in
>>turn started the extinction of anaerobes and the rise of aerobic
>>organisms. 
>>
>>If these notes are relatively accurate, do we have an ballpark idea of
>>the length of time it took for the extinction of anaerobic organisms? 
>>(e.g. tens or hundreds of millions of years?)  Regards,  Brett Aubrey.
> 
> It seems to be taking forever.  That extinction is still not complete.
>  As I sit here my gut is loaded with an anaerobic bacterium
> (Bacteroides), for example.  So is yours.
> 

OK, so Brett didn't know how to properly phrase the question. But do you 
know if there is any good information on just how quickly environments 
changed from low to high redox potential, and how quickly populations 
changed from predominantly obligate anaerobes to a mix of aerobic, 
facultative, and anaerobic forms?

Yours,

Bill Morse
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