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Author Topic:   Cyanobacteria weren't first, but last?
Quetzal
Member (Idle past 5983 days)
Posts: 3228
Joined: 01-09-2002


Message 2 of 7 (21575)
11-05-2002 6:08 AM
Reply to: Message 1 by blitz77
11-05-2002 2:16 AM


Oddly enough, cyanobacteria have not been considered to be the earliest forms of life - not even the earliest photosynthetic forms of life (look up the green bacteria Chloroflexus aurantiacus - the probable evolutionary precursor to cyanobacteria). The abstract of the actual article (vice the press release you cited), COULD CYANOBACTERIA HAVE PROVIDED THE SOURCE OF OXIDANTS FOR BANDED IRON FORMATION indicates only that Blank is arguing for about a 0.5 gy difference between the expected origin of cyanobactera around 2.8 gya, and her hypothesis of 2.3 gya. I should point out that Blank also states in the abstract:
quote:
At this time, this hypothesis is not strongly supported, because some geologic indicators support it, while others do not.
If you read the cited abstract, you'll note she's talking about the banded iron formations requiring a different mechanism than cyanobacteria poop. Ask one of the geologists.
She's also not the first to come up with the late arrival of cyanobacteria - Feng, et al, for instance in this article from 1997, Determining divergence times with a protein clock: Update and reevaluation mentions 2.1 gya cyanobacteria and Gram-positive and Gram-negative eubacteria divergence, with the divergence of archaea and eubacteria between 3 and 4 billion years ago. Or maybe The origin of atmospheric oxygen on Earth: The innovation of oxygenic photosynthesis?
Now, given that it's you posting this, blitz, we're to assume that somehow the press release you quoted refutes evolution, correct? Would you care to expand on just HOW changing the date of the emergence of cyanobacteria is supposed to do that?

This message is a reply to:
 Message 1 by blitz77, posted 11-05-2002 2:16 AM blitz77 has replied

Replies to this message:
 Message 3 by blitz77, posted 11-07-2002 1:03 AM Quetzal has not replied

  
Quetzal
Member (Idle past 5983 days)
Posts: 3228
Joined: 01-09-2002


Message 7 of 7 (26474)
12-13-2002 1:39 AM
Reply to: Message 6 by Sepiraph
12-12-2002 9:07 PM


Hey Sep!
Actually blitz's "point" was pretty much obliterated waaay up in my first post on this thread when I pointed out that cyanobacteria weren't the first photosynthetic organisms on Earth. Green bacteria like Chloroflexus were the precursors to cyanobacteria. I would bet (and this is opinion only) that there were bacteria species that were transitional between the sulfur bacteria and the green bacteria. Blitz simply slid past that bit to continue reasserting his original claim.

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 Message 6 by Sepiraph, posted 12-12-2002 9:07 PM Sepiraph has not replied

  
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