The oldest evidence for microbial life has been found in Greenland, with fossilized 3.7 billion year old stromatolites (layered bacterial colonies) found in the rocks. Here’s what they look like:
And here’s the abstract of the paper:
Biological activity is a major factor in Earth’s chemical cycles, including facilitating CO2 sequestration and providing climate feedbacks. Thus a key question in Earth’s evolution is when did life arise and impact hydrosphere–atmosphere–lithosphere chemical cycles? Until now, evidence for the oldest life on Earth focused on debated stable isotopic signatures of 3,800–3,700 million year (Myr)-old metamorphosed sedimentary rocks and minerals from the Isua supracrustal belt (ISB), southwest Greenland. Here we report evidence for ancient life from a newly exposed outcrop of 3,700-Myr-old metacarbonate rocks in the ISB that contain 1–4-cm-high stromatolites—macroscopically layered structures produced by microbial communities. The ISB stromatolites grew in a shallow marine environment, as indicated by seawater-like rare-earth element plus yttrium trace element signatures of the metacarbonates, and by interlayered detrital sedimentary rocks with cross-lamination and storm-wave generated breccias. The ISB stromatolites predate by 220 Myr the previous most convincing and generally accepted multidisciplinary evidence for oldest life remains in the 3,480-Myr-old Dresser Formation of the Pilbara Craton, Australia. The presence of the ISB stromatolites demonstrates the establishment of shallow marine carbonate production with biotic CO2 sequestration by 3,700 million years ago (Ma), near the start of Earth’s sedimentary record. A sophistication of life by 3,700 Ma is in accord with genetic molecular clock studies placing life’s origin in the Hadean eon (>4,000 Ma).
I’ve emphasized the last sentence for a reason. We’ve known for a long time that life arose early in Earth’s history. Geochemistry and the genetic clock have told us that life arose about 4 billion years ago, very shortly after it cooled from a molten state. What these fossils are are the first visible physical evidence of the existence of cellular life. They confirm what we already know. There’s nothing in the existing body of evolutionary evidence to suggest that we can’t find even older cellular fossils.
But, you know that won’t stop creationists from claiming that this discovery is a problem for science.
Reasons to Believe is an old Earth creationist organization — they have no problem with the idea that the earth is 4.5 billion years old. However, they do insist that life arose by magic, poofed into existence by their supernatural deity, so they desperately want to argue against the evidence of a natural origin. Fuz Rana wrote about this discovery, saying Science News Flash: 3.7 Billion-Year-Old Fossils Perplex Origin-of-Life Researchers
.
I read the paper. Nowhere in it is anyone “perplexed” or even “surprised”. Quite the opposite: the authors point out how this fits just fine with existing models of the history of life. Rana has to really work hard to twist the story.
The researchers who recovered and analyzed the Isua stromatolites expressed similar surprise:
“The complexity and setting of the Isua stromatolites points to sophistication in life systems at 3,700 million years ago, similar to that displayed by 3,480–3,400 million-year-old Pilbara stromatolites.”
From a naturalistic perspective, the only way for these researchers to make sense of this discovery is to conclude that life must have originated prior to 4 billion years ago. They state: “This implies that by ~3,700 million years ago life already had a considerable prehistory, and supports model organism chronology that life arose during the Hadean (>4,000 million years ago).”
Oh, wait. Where do you see surprise
in any of those quotes? That makes even less sense when you go back to the paper and look at that quote in context.
The recognition of ~3,700-Myr-old biogenic stromatolites within Isua dolomites indicates that near the start of the preserved sedimentary record, atmospheric CO2 was being sequestered by biological activity. The complexity and setting of the Isua stromatolites points to sophistication in life systems at 3,700 Ma, similar to that displayed by 3,480–3,400-Myr-old Pilbara stromatolites. This implies that by ~ 3,700 Ma life already had a considerable prehistory, and supports model organism chronology that life arose during the Hadean (> 4,000 Ma).
Rana left that bit off.
RtB really doesn’t like the actual way that origins of life researchers think nowadays. LIFE IS CHEMISTRY. The origin of life was almost certainly not a chance event, but a product of geochemical processes that would have begun as soon as conditions were locally suitable. No one considers it surprising anymore that the chemical reactions that preceded life (and the boundary between “chemical reactions” and “life” is extremely fuzzy) would have emerged as soon as opportunity arose. The directions that life would have taken after complex biochemistry started building up would have been shaped by chance, but otherwise, no, we expect that abiogenesis, or at least the conditions that would lead to abiogenesis, was a product of necessity rather than chance.
So this is a paper that repeatedly states the good fit between the discovery it describes and existing theory, and RtB repeatedly insists that the paper says the exact opposite. This is not honest.
Here’s something else that is dishonest: Rana claims this discovery supports the Bible’s model of the origin of life. Disconnect your bullshit meter before reading the next quote, because otherwise it’s going to go sproing and send shrapnel flying all over the room.
While the discovery of 3.7 billion-year-old stromatolites confounds evolutionary explanations for life’s origins, it affirms RTB’s origin-of-life model. This model is derived from the biblical creation accounts and make two key and germane predictions: (1) life should appear on Earth soon after the planet’s formation; and (2) first life should possess intrinsic complexity. And both of these predictions are satisfied by this latest advance.
His point (1) does not distinguish his creationist model from an evolutionary model, since biology and chemistry say exactly the same thing. However, it’s false because the Bible says nothing specific about the origin of cellular life. The authors of the Bible didn’t even know about cells, or genes, or molecules, or hydrogen, or reduction/oxidation reactions, or any of the stuff that is the foundation of the models Rana is so blithely appropriating. His holy book is a sucking black hole of ignorant rationalizations, not a source of theory or evidence.
His point (2) is also false. This discovery says nothing about the “first life” or whether that first life had “intrinsic complexity” (whatever the hell that is). These are 3.7 billion year old fossils. The authors point out that models of life’s origin suggest that “first life” would have appeared approximately 4 billion years ago.
Do the math. 4 billion – 3.7 billion = 300 million years.
Maybe someone needs to inform the crew at RtB that 300 million years is a very, very long time.
They can keep poring over their sacred book, but I’m pretty sure there is nothing anywhere in the Bible that’s going to help them understand geo- and bio-chemistry going on over long periods of geological time.
It’s also not going to help them understand evolution. Stromatolites aren’t in the holy book, either, nor is the fact that it was going to take a few billion years of evolution to get from single-celled bacteria to arrogant, delusional multicellular apes who think grandpa’s goofy stories are immutable truth.
Nutman AP, Bennett VC, Friend CR, Van Kranendonk MJ, Chivas AR (2016) Rapid emergence of life shown by discovery of 3,700-million-year-old microbial structures. Nature doi: 10.1038/nature19355.
And if I hide my head under my pillow the real world goes away (except if it pokes its furry nose under the pillow and gives me a right licking).
Perhaps it should be pointed out to them that this evidence pushes the “earliest” date back only about 200-300 million years before the Pilbara stromatolites, which is a wink of time. So indeed, this is no surprise, and we should not be surprised if even older evidence emerges.
By the way, at the original release of the paper a few weeks ago…and through the media hoopla…there were some cautious voices among scientists. As one scientist put it, these rocks are extremely deformed so the stromatolite interpretation isn’t rock solid. I suppose it’s too soon for further confirmation.
A creationist who’s being dishonest.
What else is new.
PZ, perhaps you’d better ignore them until they say something that’s factually correct.
Now that would be news.
There is a criticism that the structures could be an artifact, called a ‘flame structure’, where a deeper muddy layer squirts up into an upper layer. But the structures are finely lamellated into sub-layers (I don’t think a flame structure would do that), and there is an isotopic signature of biology in the rocks.
So… maybe?
One detail that irritates me is , when someone Points out that life apparently emerged early, and thus may emerge in many places in space, journalists immediately conflate (simple) life with complex life, and even intelligence.
Would it be possible to create more detailed terminology?
As in “the stromatolites prove the early emerence of single-cell (or just CG) life”.
Naah. The journalists will exaggerate the claims anyway.
BTW is this the layer that shows when the Engineers arrived to Earth, or would that be the Pilbara layer?
Typo at comment # 5. .Should be “SC Life”.
I am too tired to type correctly.
The mildly deranged penguin is very disappointed. She thought the original “CG Life” meant “Cheese Good Life”, true on multiple levels.
As reported eg on the BBC News website, there’s some controversy over whether these are actually stromatolites. YECs have by contrast either ignored the story or spuriously questioned the age of the rocks (I forget the exact details but I flagged this at the community forum of the British Centre Centre for Science Education). And OECs are doing what you report here.
I commented here on 2 September:
http://www.forums.bcseweb.org.uk/viewtopic.php?f=18&t=2967&start=1680
So what do old Earth creationists think that we need 3.7 billion years for? I mean, biologists see bacteria and archaea as having a great deal of diversity and room to evolve before eukaryotes arise and open up a bunch of new paths for mutation. YECs have a model where larger scale evolution can’t happen* because they think the age of the universe is apparently on the scale of the history of human civilization. So is OEC just an attempt to cling to the most personally meaningful parts of creationism without thinking the parts they concede through?
* Of course, I’ve never seen any of them admit larger scale evolution could work over millions of years, even if that doesn’t conflict with their insistence life was created recently.
My comments there dated 5 Sept also refer.
Need? More acknowledge: The Earth is old. They are trying to reconcile that fact with their insistence life was poofed into existance by magic sky faeries.
There are multiple kinds of OEC. Not all plonk life down recently on an old planet, some plonk simple life down when the planet was young and let it evolve, sometimes with additional tweaking by magic sky faeries and/or saying humans are not part of any evolutionary bush; and other variants. Besides the Earth is old, I think the other thing OECs all have in common is the plonking down of life by magic sky faeries; that is, that abiogenesis is not a natural — geochemical — process, but a magic sky faerie creation, a poofing into existence.
@robro #2, as memory serves, other discoveries are merely supported by this sample, assuming that it is correct (there’s some question as to what the sample is, but it agrees with current theories and previous discoveries).
Still, if one really want one’s noodle baked, could there have been life before the Theia impact event? If so, there’s a slight chance that there are fragments that escaped the impact and orbit and are now in their own orbit, which may one day be discovered.
I do disagree with one thing though, from abiogenesis through colonial life, I suspect we’d see very similar organisms. The chemistry isn’t different, the problems to resolve are the same, the solutions would likely be quite similar. Some argue against that, toward substantially different solutions evolving. I suspect that major divergences would occur at the complex organism stage, when competition, niches in a developing biome sphere create opportunities and pressures.
Still, considering the phenomenal variety within the earth’s fossil record, isn’t it mind boggling what one can build with a mere four letters? :)
One ponders what the creationists would make of life forms on other bodies, where the chemistry is substantially different and hence, the alphabet is substantially different. Even money, their skulls would implode.
Nah, they’d handwave it off with, “Oh, that’s the heavens, they don’t count” or something equally vapid.
“I do disagree with one thing though, from abiogenesis through colonial life, I suspect we’d see very similar organisms. The chemistry isn’t different, the problems to resolve are the same, the solutions would likely be quite similar.”
Do you know nothing about bacteria? Or evolution?
@wzrd1 I think your onto something with Theia. something like this?: https://thefamoussandhogs.bandcamp.com/album/theias-mammon-skonis-ikon
@Mark Dowd #15, actually, I do. We see similar approaches to resolve similar problems, convergent evolution of solutions and nothing applied to resolve a problem as to “appear alien” compared to the entirety of the species.
When you consider the age of the species in general and the immensity of the planet compared to their colonies and the variety of environments that they’re found in, the same chemical tools, using the same methods of creating them evolve or re-evolve. Some DNA is tightly conserved, as if it wasn’t, the essential cellular machinery of life would be lost and the cell wouldn’t survive.
But, in other areas, the same general root stock chemicals are available for the bacteria to adapt itself to use in different ways. So, even if a bacteria enters a new niche that it had lost the processing ability of some local concentrations of elements, it re-revolves in a very similar way to other bacteria have evolved. The chemistry restricts solutions.
In short, we see bacteria that retain common genetics to some extent, we don’t see bacteria like dragons or something equally alien, where every common allele has evolved away, due to the tightly conserved areas that remain common for the chemistry of this earth.
Which also rather also undermines the occasionally revived panspermia hypothesis, as one wouldn’t expect such tightly conserved DNA present if an organism originated from a substantially different environment, when speaking of both conditions and chemical prevalence.
Poorly stated, but I was tired when I made my initial comment and I’m still a bit tired. Working midnight shift is a pain.
Perhaps they are making the (inexcusable) mistake of disregarding 300 million as it is not very large compared to 4,000 million. But as a testament to just how fucking long 300 million years it, going back that far from the present day is far back enough to predate the existence of… all dinosaurs.
@Holms #18 and ironically, due to various economic collapses over the years, 300 million years is how old I’ll be before I can afford to retire.
OK, lousy joke. It only feels like it’d take nearly one third of a *billion* years.
Which really is the heart of the problem, actually comprehending internally, something like 300 million (hell, there are around 320 million people on this continent, most can’t even grasp that number of people, let alone such a vast length of time) years. Nearly one third of a billion. Around 3.33 degrees warmer sun. Continents are in vastly different configurations. Hell, the atmosphere could be entirely different in constituency, with a lot more oxygen than before or no oxygen present.
In such an amount of time, life can entirely remodel a planet! Yet, most cannot begin to actually firmly grasp that number in their minds.
https://the-sieve.com/2013/11/06/human-minds-vs-large-numbers/
Of course, then there’s things like Graham’s number. Something I consider, while realizing that I manage to figure out 20 by taking off my shoes and recalling, the last time I counted to 21, I was arrested.
The officer thought I was sticking my tongue at him.
My, why low thoughts you have! I only go there when I have to count to 22.