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Earth Canada Science

3.77-Billion-Year-Old Fossils Found, Could be Earliest Evidence of Life On Earth (theguardian.com) 82

An anonymous reader shares The Guadian report: Scientists say they have found the world's oldest fossils, thought to have formed between 3.77bn and 4.28bn years ago. Comprised of tiny tubes and filaments made of an iron oxide known as haematite, the microfossils are believed to be the remains of bacteria that once thrived underwater around hydrothermal vents, relying on chemical reactions involving iron for their energy. If correct, these fossils offer the oldest direct evidence for life on the planet. And that, the study's authors say, offers insights into the origins of life on Earth. "If these rocks do indeed turn out to be 4.28 [bn years old] then we are talking about the origins of life developing very soon after the oceans formed 4.4bn years ago," said Matthew Dodd, the first author of the research from University College, London. With iron-oxidising bacteria present even today, the findings, if correct, also highlight the success of such organisms. "They have been around for 3.8bn years at least," said the lead author Dominic Papineau, also from UCL.
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3.77-Billion-Year-Old Fossils Found, Could be Earliest Evidence of Life On Earth

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  • by Anonymous Coward

    Why do we need more evidence of life on Earth? Haven't we already proven that life exists on Earth?

    (Note: this is a joke)

    • We know that there is life om Earth ... the question is: is the life on Earth intelligent ?

    • by The Raven ( 30575 ) on Wednesday March 01, 2017 @06:21PM (#53958207) Homepage

      I know it's a joke, but just for the sake of discussion I'd like to address it.

      Finding out that life took 'only' 100 million years to appear after the formation of liquid oceans makes it a lot more likely that life (as we know it) is ubiquitous in favorable conditions. It means that if we are ever able to investigate the cosmos, we may find that most worlds that have liquid water have at least primitive life on them (rather than 'some' or 'occasional'). And there is always the possibility of life as we don't know it; life in gas giants, on neutron stars [wikipedia.org], in the gluon soup of the first moments of the cosmos (Stephen Baxter, but I can't remember which story), in the accretion disks of black holes [wikipedia.org], in the photosphere of stars [wikipedia.org].

      There are so many ways that organization could form out of chaos, and that life would be invisible to us. If there was a form of life that lived in our sun's photosphere how would we tell it existed? We only recently learned that there are microbes in our upper atmosphere that is evolved to survive there permanently... and we flew through it for decades!

      The more alien life is, the easier it is for us to overlook or not recognize the signs of its existence. Not only that, but the less likely we are to visit (or closely investigate) the environment it lives in because that environment is inhospitable to us.

      So yeah... finding out that life evolved early on on Earth is fascinating, and it really lends weight to the possibility of life being all over the place... even where we have not tried to look.

      • by MightyMartian ( 840721 ) on Wednesday March 01, 2017 @06:27PM (#53958249) Journal

        I remember reading an observation by a chemist or molecular biologist years ago that abiogenesis events might go on all the time, but the problem for any new protolife is that if it appears in an already active biosphere where a fair portion of the existing organisms are very very good at gobbling stray bits of organic material, it's not going to last long at all.

        • by tsa ( 15680 )

          That is not hard to come up with. What's hard to come up with is a scenario where only one of all those different early life forms on this enormous planet of ours manages to prevail very very early in the history of said planet and bethe oldest ancestor of all life on Earth as we know it today.

      • Just for the sake of completeness I would like to mention that it's possible we just got lucky and got seeded from outer space early on. All it takes is a single organism in the right place at the right time.
    • by PPH ( 736903 )

      Earliest? Do you mean before my morning coffee?

  • Huh? (Score:4, Funny)

    by Frosty Piss ( 770223 ) * on Wednesday March 01, 2017 @05:30PM (#53957785)

    There must be something wrong with their testing protocol, we all know that the earth is about 6,000 years old.

  • by Anonymous Coward

    Their DNA contained only 50% chicken.

  • SUBJECT REQUIRED (Score:5, Interesting)

    by beelsebob ( 529313 ) on Wednesday March 01, 2017 @05:44PM (#53957923)

    With life being at least 83% as old as the planet according to this result, it makes me begin to wonder "has life been on earth ever since it formed?"

    That's clearly not a question we're going to answer today, but it might have drastic impacts on the drake equation if there was some requirement for life that has to happen as the planet forms.

    • what if that life arrived as "contamination" from elsewhere?

      • Re:SUBJECT REQUIRED (Score:5, Interesting)

        by MightyMartian ( 840721 ) on Wednesday March 01, 2017 @06:22PM (#53958211) Journal

        I'm not a huge fan of panspermia in general, as it seems to add an additional step to a problem, but really just pushes the question back. I can concede that it is possible that Mars, which may have been more conducive to life earlier, may have been the source of life on Earth, but until we find some evidence that life actually existed on Mars at some point, and further can show enough molecular commonality with life on Earth, I think Occam's razor suggests we have to stick for the moment with life being indigenous to Earth. That being said, even if we found life on Mars that appeared to be part of the same twin-nested hierarchy as life on Earth (in other words, we're all on the same family tree), that still wouldn't really answer the question, since it's easily conceivable that the transit could have been the other way; Earth to Mars.

        What we do know right now is that some of the most ancient genes suggest these early organisms at the root of the tree of life were autotrophic and probably hung around deep sea vents in waters rich in iron and sulfates (this is the idea behind the iron-sulfur world hypothesis [wikipedia.org]). While this doesn't necessarily discount Mars either, as Mars in this early era had oceans and was very likely geologically active, it still suggests to my mind that Earth is still a pretty clear contender for the source of the life we see today.

        A lot will depend on whether we can find other life in the solar system. If we go to Mars or Europa and end up finding organisms that have a clear molecular relationship to life on Earth, it certainly proves the limited form of panspermia happened, whereas if it turns out there is no evident genetic relationship, then that ought to tell us life is pretty damned common in the universe, and even in conditions like the Hadean Epoch, when Earth was quite literally at points a hell, life can not only evolve but possibly even flourish.

        • I'm not a huge fan of panspermia in general, as it seems to add an additional step to a problem, but really just pushes the question back.

          Surely it's more likely that life developed at all, compared to life developing on one particular planet. I agree there's the additional probability/step of getting life from there to here, but that would balance it out to some extent.

          I also wonder how similar life elsewhere turns out in case there's no panspermia. For example, the handedness of molecules in Earthly life is related to CP violation of physics, which I expect to be the same all around.

          • I guess some of it depends on how much imagination you want to apply to the potential kinds of life. If we imagine that life has a few key requirements; namely some sort of universal solvent, plentiful energy, and chemistry capable of creating fairly sophisticated molecules and chains of molecules, then I think we're probably looking at the classic "organic soup" of water, complex organic compounds, or the capacity to produce them, and ready sources of energy. If that's the case, then I imagine that while t

            • by rtb61 ( 674572 )

              How long can a fossil survive ie how long would it take for every rock on a planet to be recycled. Rock to not rock and back again and again and again. What limits are there upon survivability of fossils over time, especially larger ones. The only reason larger fossil are never discovered further back in surviving rock history is because they simply did not survive the rock recycling process.

              • There's enough of the ancient crust to demonstrate that there were no large complex lifeforms before 600 million to a billion years ago.

                • I'd just like to add to that that one of the indirect ways we know that larger more complex multicellular lifeforms didn't involve into the last billion years is because oxygen levels didn't normalize through the Great Oxygenation Event until about a billion years ago. Oxygen is pretty darned important to most, if not all multicellular organisms, but is toxic to many anaerobic organisms, which are almost inevitably single-celled, and which would have dominated for much of Earth's history.

          • by khallow ( 566160 )

            For example, the handedness of molecules in Earthly life is related to CP violation of physics,

            I strongly doubt that. I would suggest instead that handedness is a result of it being more efficient to have key molecules of one handedness rather than both. Then it becomes random chance which handedness becomes dominant, assuming there was ever a competition in the first place rather than handedness manifesting from the beginning.

        • Re:SUBJECT REQUIRED (Score:4, Informative)

          by Sique ( 173459 ) on Wednesday March 01, 2017 @08:02PM (#53958853) Homepage
          I agree wholeheartedly, and I want to add some other arguments against panspermia.

          We know that simple organic compounds form spontaneously from anorganic matter. Amino acids like lysine or nucleic acids for instance appear, if you treat a mixture of water, carbondioxide and nitrogenium with lightning. So yes, organic compounds have been found in comets or meteorids, but that's because they are quite aboundant in space and form sponaneously given the right conditions.

          Yes, some of those compounds on Earth might have arrived via a cosmic impact, but it seems they were just the literal drop in an ocean of organic compounds formed on Earth itself. And an asteroid impact sets free a large amount of energy, comparable to a nuclear detonation, which means that any more complex molecules have been destroyed by the impact.

          And allthough organic matter forms spontaneously from anorganic matter, and organic matter can be transported via comets and other cosmic debris, if it arrives somewhere where life might form, there is a high probability that life has already formed there, when the organic matter arrives from space, and then it's just some additional nutrient for the local life forms, but it will not be the origin of a completely new life.

          • But there is zero evidence in the lab that amino acids self-assemble into self-replicating self-programming robots (aka organic life). What if that takes billions of years to happen by chance? As we explore space we may find that is indeed the case.

            • by Sique ( 173459 )
              As I said: I doubt that any long compounds of amino acids or nucleic acids survive a meteor strike.
            • But there is zero evidence in the lab that amino acids self-assemble into self-replicating self-programming robots

              Do try to keep within a couple of decades of the cutting edge. It is ages since self-catalysing oligonucleotides have been demonstrated in early-Earth analogues. It's not life, but it's another step in the right direction.

    • but it might have drastic impacts on the drake equation if there was some requirement for life that has to happen as the planet forms

      But that wouldn't even make sense. Because the planet, "as it was forming," was a completely life-hostile seething ball of super-heated molten stuff. Life-friendly things present at that time would have been cooked into oblivion. Things had to cool down and get wet, first.

      • Re:SUBJECT REQUIRED (Score:5, Interesting)

        by MightyMartian ( 840721 ) on Wednesday March 01, 2017 @07:10PM (#53958539) Journal

        That describes parts of the Hadean Epoch, and in particular the early parts, but there is some evidence that even during the Hadean Epoch there was liquid water, possibly even oceans. From https://en.wikipedia.org/wiki/... [wikipedia.org], it states that even though surface temperatures were much higher, the much higher atmospheric pressure meant that liquid water could exist. Considering some evidence that the earliest organisms were autotrophic and lived in an environment very much like existing deep sea vents, one can surmise that while this environment would be pretty damned hostile, it would still have had the critical ingredients; water, complex organic chemistry and an abundance of energy.

    • it might have drastic impacts on the drake equation if there was some requirement for life that has to happen as the planet forms.

      The Drake Equation allows for the possibility of exogenesis which thusly nullifies any requirements you might think to add to planets.

      fl = the fraction of planets that could support life that actually develop life at some point <-- allows for exogenesis.

      • The point was that it causes that coefficient to be rather low if some specific condition is needed at some very specific time in the planet's life, rather than generally being something that can happen at any moment.

    • "it might have drastic impacts on the drake equation if there was some requirement for life that has to happen as the planet forms."

      I'd have gone the opposite direction, actually. I'd say it would have drastic impact on the Drake Equation if life could form in an environment as hostile as the earth 3.87 bn years ago - iirc that was only very shortly after (we believe) water oceans formed.

  • cue the John McCain jokes

    • No no no... I'm pretty sure some of the fossils on the road around here pre-date McCain by at least 100M years.

  • by mykepredko ( 40154 ) on Wednesday March 01, 2017 @05:59PM (#53958051) Homepage

    When I RTFA and saw the reference to hematite, I wondered if this is similar to possible evidence of life found on Mars: http://mars.nasa.gov/mer/scien... [nasa.gov]

    Any biologists out there care to explain if this is similar or different?

    If this is similar, does this provide a clue as to how life starts to evolve on a planet?

    • When I RTFA and saw the reference to hematite, I wondered if this is similar to possible evidence of life found on Mars

      Funny, whenever I see a reference to hematite I think of Dwarf Fortress.

    • Try reading the FP [sci-hub.io] instead of reading a hastily-written summary prepared by journalists who don't actually understand what they're regurgitating from the press release. There's a reason that scientists write papers, after all, rather than communicating by press release.

      Personally, I take the presence of authigenic haematite as evidence that there was at least some organism in the environment increasing the oxygen activity of the system.

  • The vice-president of the USA believes that the world is only 6,000 years old. He knows, and he would not lie to us, would he?
    • by gtall ( 79522 )

      That's the problem, he believes he's telling the truth. "The Lord is my Shepard, I shall not think."

  • The Guadian, eh?

    I might be inclined to believe that it's a subtle joke [ulrikchristensen.dk], if it wasn't for the fact that it was posted by manishs who is such a mong he has 21 copies of chromosome 3.

  • Often scientists end up discovering natural processes that can resemble the patterns of life, both physical and chemical. Error on the side of skepticism.

  • Adam & Eve are gonna be pissed!

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