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Author Topic:   Cyanobacteria weren't first, but last?
blitz77
Inactive Member


Message 1 of 7 (21564)
11-05-2002 2:16 AM


An article on Eurekalert has an article saying that cyanobacteria, the supposed earliest life on earth which produced oxygen, saying that they came ~1 billion years after than assumed. In Carrine Blank's model, sulfur-loving bacteria came ~2.4 billion years ago and the cyanobacteria about 100 million years about that. If this theory is correct, how do banded iron formations, etc fit in? Blank used genetic family trees to support this. Using the genetic tree, Blank was able to show that cyanobacteria would branch off last of the primitive bacteria.

Eurekalert


Replies to this message:
 Message 2 by Quetzal, posted 11-05-2002 6:08 AM blitz77 has responded

  
Quetzal
Member (Idle past 3980 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 responded

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 Message 3 by blitz77, posted 11-07-2002 1:03 AM Quetzal has not yet responded

  
blitz77
Inactive Member


Message 3 of 7 (21754)
11-07-2002 1:03 AM
Reply to: Message 2 by Quetzal
11-05-2002 6:08 AM


Maybe this isn't about evolution but abiogenesis, but since it is dealing with the reducing/oxidizing early atmosphere it can't really be classified in abiogensis/origin of life as it is talking about what organisms could have converted the supposed early reducing atmosphere into an oxidizing atmosphere. This may be considered as further evidence against an early reducing atmosphere--because otherwise you would need some other organism to produce oxygen, and no other candidate has been put forward. Until then, this is further evidence against an early reducing atmosphere.

[This message has been edited by blitz77, 11-07-2002]


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 Message 2 by Quetzal, posted 11-05-2002 6:08 AM Quetzal has not yet responded

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 Message 4 by John, posted 11-07-2002 1:30 AM blitz77 has responded

  
John
Inactive Member


Message 4 of 7 (21756)
11-07-2002 1:30 AM
Reply to: Message 3 by blitz77
11-07-2002 1:03 AM


quote:
Originally posted by blitz77:
This may be considered as further evidence against an early reducing atmosphere--because otherwise you would need some other organism to produce oxygen, and no other candidate has been put forward.

The article you linked-to in your post is discussing these other organisms.

Note that per the article cited, cyanobacteria are not the EARLIEST bacteria, but came along after the sulfer loving bacteria. It does not say that NO BACTERIA came before the cyanobacteria.

------------------
www.hells-handmaiden.com


This message is a reply to:
 Message 3 by blitz77, posted 11-07-2002 1:03 AM blitz77 has responded

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 Message 5 by blitz77, posted 11-07-2002 1:48 AM John has not yet responded

  
blitz77
Inactive Member


Message 5 of 7 (21757)
11-07-2002 1:48 AM
Reply to: Message 4 by John
11-07-2002 1:30 AM


quote:
Note that per the article cited, cyanobacteria are not the EARLIEST bacteria, but came along after the sulfer loving bacteria. It does not say that NO BACTERIA came before the cyanobacteria.

Of course, according to the article cyanobacteria aren't the first bacteria. But my point still stands-or are you suggesting these sulfur-loving bacteria produced the first oxygen in the reducing atmosphere?

[This message has been edited by blitz77, 11-07-2002]


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Replies to this message:
 Message 6 by Sepiraph, posted 12-12-2002 9:07 PM blitz77 has not yet responded

  
Sepiraph
Inactive Member


Message 6 of 7 (26455)
12-12-2002 9:07 PM
Reply to: Message 5 by blitz77
11-07-2002 1:48 AM


quote:
Originally posted by blitz77:
Of course, according to the article cyanobacteria aren't the first bacteria. But my point still stands-or are you suggesting these sulfur-loving bacteria produced the first oxygen in the reducing atmosphere?

[This message has been edited by blitz77, 11-07-2002]


Well, whether true or not, that's what they're teaching in undergraduate microbiology courses these days.


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 Message 7 by Quetzal, posted 12-13-2002 1:39 AM Sepiraph has not yet responded

  
Quetzal
Member (Idle past 3980 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 yet responded

  
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