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Australia Science

World's Oldest Fossils Found In Australia 85

Dexter Herbivore sends this quote from the Washington Post: "Scientists analyzing Australian rocks have discovered traces of bacteria that lived a record-breaking 3.49 billion years ago, a mere billion years after Earth formed. If the find withstands the scrutiny that inevitably faces claims of fossils this old, it could move scientists one step closer to understanding the first chapters of life on Earth. The discovery could also spur the search for ancient life on other planets. These traces of bacteria 'are the oldest fossils ever described. Those are our oldest ancestors,' said Nora Noffke, a biogeochemist at Old Dominion University in Norfolk who was part of the group that made the find and presented it last month at a meeting of the Geological Society of America."
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World's Oldest Fossils Found In Australia

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  • Lightweight (Score:5, Funny)

    by LordLucless ( 582312 ) on Wednesday January 02, 2013 @06:31AM (#42448889)

    I'm sure there's plenty of older ones in Canberra

  • by ripnet ( 541583 ) on Wednesday January 02, 2013 @06:33AM (#42448895)
  • its where all the UK's old entertainers go to retire.....
  • by Anonymous Coward

    I didn't RTF, but how did they determine age for something like that, which Carbon-14, I think, couldn't date?

    • Re: (Score:3, Funny)

      by Anonymous Coward

      Probably tree rings.

    • Re:How Old? (Score:5, Informative)

      by Guido von Guido II ( 2712421 ) on Wednesday January 02, 2013 @09:10AM (#42449477)

      The article doesn't actually say and the Washington Post just links to the article abstract, but C-14 dating isn't used except for recent material because of its small half-life. There are a wide variety of methods used for older rocks (see here [wikipedia.org]). For instance, rubidium-strontium dating might be used, since rubidium-87 has a half life of 50 billion years. Rubidium-strontium can be used for isochron dating [wikipedia.org] as well, which doesn't require any assumptions about the amount of the daughter nuclide in the sample.

      Having said that, I don't have any details on the methods actually used to date rocks in this particular region.

    • They would have dated the rocks these fossils were found in. C-14 dating is only good for relatively recent dating (up to ~60000 yrs). They probably used K-Ar or U-Pb dating, although there are a few more options [wikipedia.org].
  • by Anonymous Coward

    The article contains the comment "Those are our oldest ancestors". That got me thinking... Since bacteria are asexual and reproduce by division then, technically, the ancestor of two bacteria was destroyed when it split into it's two children. If this is true then any fossilised bacteria must, since they are dead and in one piece not two, not have reproduced. If they didn't reproduce they can't be the ancestors of anything...

    • by Anonymous Coward

      But their twins could be.

    • What the article discusses is the age of a rock formation that appears to have been caused by bacterial activity, not any direct structural remnant of the bacteria themselves.
      • so this is the oldest known poop every discovered?

        • by AlecC ( 512609 )

          For poop, you need a bowel. Which was not invented until the Cambrian, or just before, about 540 million years ago. So these bacteria pre-date any poop, let alone discovered poop, by getting on for three billion years.

          Yes, once upon a time the world was not full of shit. Back then, shit didn't happen.

          No shit, Sherlock.

    • The same issue exists, albeit to a smaller extent, with any fossil. There's no guarantee that an individual that reproduced will be fossilised, or vice versa.

      So much data on our planet's history is lost to the bitter march of time. But we're winning! Eat that, time!

    • I had a similar thought. Granted that we share the same molecular machinery, but it seems to me that we probably evolved from the hosts the bacteria fed on, not from the bacteria themselves. Unless they ate rock, in which case we evolved from the hosts their mutations ("descendants") fed on. For me, the jump from asexual to sexual reproduction is the really interesting inflection point. Do we really believe that an ordinary mutation caused that? (IANAE).
      • Bacteria has a lot of interesting sexual (or sexual like) traits, like sharing chromosomes by way of membrane tunnels. So something like it has evolved many times over. But evolution doesn't use "hopeful monsters" (macroscale mutations), but proceeds mostly along darwinian pathways: small, survivable, on average fitness increasing steps. (See near neutral genetic drift and genetic bottlenecks for variation driven pathways.)
    • by rtb61 ( 674572 )

      Why would the original be defined as destroyed in splitting, that is illogical. You have an original living mass, which internal reproduces a copy of it's inner functions and DNA. The internalised copy is then ejected within a new cell wall. You always have the original up until something consumes it or it is destroyed via any one of countless methods.

      • In fact, the original (parent) usually ages as we do, as its continuing "half cap" membrane + associated cellular machinery will accumulate cellular damage and die after some ~ 200 divisions. (Seen in some experiments on modern bacteria.)
    • by jc42 ( 318812 )

      That got me thinking... Since bacteria are asexual and reproduce by division then, ...

      That's where you went wrong. Bacteria do have a sexual reproduction process, though mostly they produce by division. Their sexual process is a lot different than ours, but it does involve two bacteria joining cell membranes, exchanging and mixing up portions of their DNA, making a few copies, and then splitting up into cells that contain mixtures of both parents' DNA. This has the usual survival advantage: The offspring that have a "better" combination of genes will do better than the other half of the

  • Like everything else down under, these bacteria coulf kill with big, nasty teeth, poisonous spines, and deadly venom.

  • With the quick appearance of algae on Earth, it makes it seems as if basic life as cyanobacteria evolves quickly from chemicals or else evolved slowly some other place but survives the depths of space (which is possible).

    However, panspermia doesn't explain multi-cellular life or backbones, something that didn't happen until just recently in the timescale, less than 500 million years. Bacterial life may arise almost spontaneously across the galaxy but advanced life obviously takes more doing. We aren't eve

"Wish not to seem, but to be, the best." -- Aeschylus