Life in the Universe Is Common, Oldest Fossils on Earth Suggest

By Jake Parks | December 21, 2017 1:59 pm


In a study published this week in the Proceedings of the National Academy of Sciences, scientists confirmed that the oldest fossils ever discovered — found in a nearly 3.5-billion-year-old rock from western Australia — contain 11 complex microbes that are members of five distinct species.

The findings not only suggest that life on our planet originated some 4 billion years ago, but also help support the increasingly widespread theory that life in the universe is much more common than we previously thought.

“By 3.465 billion years ago, life was already diverse on Earth; that’s clear,” said J. William Schopf, a professor of paleobiology at UCLA and the study’s lead author, in a press release. “This tells us life had to have begun substantially earlier, and it confirms that it was not difficult for primitive life to form and to evolve into more advanced microorganisms.”

To analyze the microorganisms, the researchers used an instrument called a secondary ion mass spectrometer (SIMS) — one of only a few in the world. By measuring the ratio of carbon-12 to carbon-13 isotopes, SIMS helped the scientists determine the microbes’ anatomies, and revealed how they lived.

“The difference in carbon isotope ratios correlate with their shapes,” said John Valley, professor of geoscience at the University of Wisconsin-Madison and co-author of the study. “Their C-13-to-C-12 ratios are characteristic of biology and metabolic function.”

Based on the chemical analysis, the researchers concluded that the 11 fossilized microbes spanned five different taxonomical groups. Some of the microbes were a type of now-extinct bacteria from the domain Archaea, while others were more similar to microbial species still around today. The analysis also suggests that the microbes existed when there was very little oxygen present in Earth’s atmosphere.

According to Schopf, the process of photosynthesis, as we know it today, had probably not even evolved yet. In fact, he thinks that oxygen did not appear on Earth until roughly half a billion years later. Because of this, oxygen would have most likely poisoned and killed the microorganisms.

Whether or not oxygen was deadly to the microbes, the results show that “these are a primitive but diverse group of organisms,” Schopf said. Their complex and varied structures at such an early point in Earth’s history demonstrate that life can take root and evolve much more rapidly than previously thought.

When combined with the fact that there are trillions of stars in the universe — and the growing consensus among astronomers that exoplanets are commonplace — the case for life existing elsewhere in the universe has never been stronger. “If the conditions are right, it looks like life in the universe should be widespread,” Schopf said.

Schopf previously described the fossils in the journal Science in 1993, and he confirmed their biological origin in the journal Nature in 2002. However, this is the first study to reveal both how complex the fossils are and to describe exactly what they are. (Schopf’s work also made news in 2015 when he helped discover a deep-sea microorganism that apparently hasn’t evolved in over 2 billion years.)

The most recent findings “will probably touch off a flurry of new research into these rocks as other researchers look for data that either support or disprove this new assertion,” said Alison Olcott Marshall, a geobiologist at the University of Kansas in Lawrence who was not involved in the study, in a press release.

“People are really interested in when life on Earth first emerged,” Valley said in a press release. “This study was 10 times more time-consuming and more difficult than I first imagined, but it came to fruition because of many dedicated people who have been excited about this since day one … I think a lot more microfossil analyses will be made on samples of Earth and possibly from other planetary bodies.”


This article originally appeared in

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  • Uncle Al

    That life is near everywhere is unremarkable, including -40 °C pore water to 2.1 GPa/100 °C at depth water. Three fruitful questions are

    …1) Does it have protein homochiral L-amino acids and homochiral D-sugars? (CIP notation is not relevant, re cysteine).
    …2) Does it pay taxes?
    …3) Does it shoot back?

    • FluffyGhostKitten

      Exactly. Finding life on another planet would be cool, but it would not be entirely surprising. If it’s intelligent, that would be even better, though that’s likely much rarer. We are almost certainly not alone in the universe, but have they come here and stuck stuff up our a**es? Most likely, no.

      • OWilson

        With half of our life on Earth, human, animal, bacterial, and viral and preying on the other half , finding life on another planet as “cool” may be an overstatement! :)

        • Mau Pham

          OWilson: your ratio of half and half is unreasonable. There must be a lot of preys to sustain much fewer predators. It’s more likely that 99% of life have to sustain 1% (that’s the same ratio in humam societies !)

          • OWilson

            Predators are not monolithic.

            They are divided up into Christians, Jews, Islamists, Fascist, Communists and Anarchists.

            Sometimes there can exist an unholy alliance between any given groups. :)

      • Uncle Al

        Terrestrial extremophiles provide industrially useful reactions whose enzymes tolerate much grief. Multiple creations, then the Vatican dances the Tijuana Two-Step. Universal homochiral life bears on the fundamental structure of physics.

        However, if it cannot play pinochle and it isn’t delicious or amusing…clean the plate and colonize. Diversity will inherit the Earth 6×3×6 ft³ each instance.

      • Michael Cleveland

        Intelligent life is probably quite common, too, since predatory success ultimately demands that predator be smarter than prey, but there seems to be an odd, very persistent, and perfectly illogical assumption that technology is the inevitable outcome in the evolution of intelligence.

        • FluffyGhostKitten

          Right. Which is why they ain’t coming here.

        • gurukalehuru

          Not illogical at all. The intelligence which can make tools has a huge evolutionary advantage over those that don’t, and tools giving rise to machines is only a half step from there.

          • Michael Cleveland

            You are making the same erroneous assumptions that drive the search, by defining intelligence in terms of technology. You have only to look around you to see the many different ways it can manifest itself, and the many different directions it can take: dogs, cats, octopi, Dolphins. Technological potential gives an evolutionary boost in a limited number of conditions, only where the potential already exists. Its absence does not preclude the evolution of intelligence.

        • Dennis Spirgen

          Do not go anthropomorphic here. You have no basis for assuming that other life would even be predatory.

          • Michael Cleveland

            This is not anthropomorphism. The nature of biological energy exchange mandates that some life forms serve as food sources for other life forms.

          • Dennis Spirgen

            You mean like the vast majority of life on Earth that produces its energy by photosynthesis?

          • Michael Cleveland

            Well, I walked right into that one, but of course, you are right. However, in my own meager defense, we were talking about intelligent life

          • Dennis Spirgen

            Exactly. The last 20 years have proven we do not even understand our own solar system thoroughly. Which means any discussion of what life “has to be” is premature.

          • Michael Cleveland

            That has been largely my point. I’m amazed at the ill-considered assumptions that underlie discussions of the search for evidence of extraterrestrial life. We have a far better chance of detecting microbes on Mars, Europa, or any of several other moons than we do of detecting radio signals from tech-based civilizations. Besides the relatively low probability of the incidence of such civilizations, there is also the problem of time. Against the age of that generation of solar systems that might harbor life-bearing planets, there is also the question of how long tech phases are viable, and our chances of being in the right time to detect them. We have been broadcasting radio for little more than a century, and are facing problems of survival which may very well be insurmountable. If civilizations with that potential take thousands of years to develop detectable technologies, which then survive for similarly short periods, the chances of overlapping detection times are very remote indeed, in all of the millions of years available for those developments to take place, unless technological life proves to be extremely common. Flash in the pan, as it were. I think SETI is a worthwhile idea, but almost certainly doomed to failure.

        • Jim Foster

          Yup, think of dolphins.

          • Michael Cleveland

            And dogs, cats, whales, octopi…the list is very long on our own planet.

  • OWilson

    Fossils can “suggest” life is “common”, but we, the epitomy of tehnological evolution have no clue!

    Life is noisy, we are noisy. But the Universe is very quiet, life wise! :)

    • Michael Cleveland

      Again the assumption that intelligence is signified only by technology. In fact, the former is probably quite common, where the latter, with so many alternative evolutionary avenues available, is almost certainly quite rare.

      • OWilson

        It is hard to see how intelligence would manifest itself without say, the technology of General Foods, or Monsanto. That would limit their diet to the weakest among them.

        And how, exactly, would they find out about the universe and the atom, without telescopes and microscopes?

        Maybe you are thinking of the “intelligence” of monkeys, cats and dogs? :)

        • Michael Cleveland

          And clearly you are not. Intelligence is most simply defined as the ability to solve problems, not as the ability to manufacture food or material goods.

          • OWilson

            I’d suggest that the ability to solve how we can feed 5 billion on this planet and keep Mother Nature’s deadly diseases at bay, is a measure of our intelligence.

            We can perhaps end in agreement that we will not be hearing from the intelligent life in the universe that is not technologically advanced.

            But in that case we must be content with merely guessing whether such life exists at all!

          • Michael Cleveland

            There are many ways of measuring human intelligence, but none have anything to do with this discussion, the point of which is that intelligence that evolves in technological directions is probably quite rare, as a matter of probabilities, since there are so many ways for intelligence to evolve that don’t lead to technology. Whales will never make to the moon on their own.

          • OWilson

            Why would they ever want to?

            Only man has that curiosity! :)

          • Michael Cleveland

            Of course, but that doesn’t change the fact that they are highly intelligent. It’s just not an intelligence that is ever likely to take on technological goals.

          • OWilson

            And of course that will limit them to their current habitat, at the mercy of Mother Nature.

            Mother Nature has killed of 99.8% of all non technical species that ever existed, so they tell us! :)

          • Michael Cleveland

            99.8% of non-technical species? I think you are arguing for the sake of argument, since this also has nothing to do with the discussion. But for the record, the disappearance of all of those species is a consequence of 3.5 billion years of evolution. It’s also noteworthy in that light that this one and only “technical species” is well on the way to generating the sixth great mass extinction in that history, which will take us right along with it.

          • drchuck1

            He is a troll.

          • OWilson

            Trolls are usually limited to one line insults! :)

          • Michael Cleveland

            No, I think he’s a kid. The general middle school level of thinking in his answers suggests junior high, or not much higher.

          • Oakie Wilson

            Ah, the inevitable insults from the intellectually bankrupt.

            What took YOU so long! :)

          • OWilson

            Ah, the inevitable ad hominem name calling of the intellectually bankrupt.

            What took you so long?

          • Michael Cleveland

            I’m not the one who called you a troll. I simply offered a more logical explanation for the fact that your responses did not contribute substantially to the question at hand, but instead, took off on unrelated tangents. Syntax, argumentative content, the general absence of logical process, and in the end, resorting to insult instead of reasoned response, indicate a juvenile level of thinking. Always good to bear in mind that it is impossible to make yourself appear smarter, more knowledgeable, better educated, or more grown up than you actually are.

          • OWilson

            No, thanks all the same! :)

          • OWilson


            So we are seeing the planet die, and all animals going extinct in just your own paltry lifetime, after at least 4,500,000,000 of managing quite nicely without you!

            You must feel really, really, special! :)

  • John C

    Life seems to be everywhere on Earth, almost from the beginning, so likely in many other places as well.

    Oddly, we have zero trace of it so far in the trillions of other stars and galaxies, and Solar system neighbors we’ve looked at.

    And we still can’t figure out how inanimate chemical precursors made the initial leap to biology.

    • John Thompson

      It’s a mockery of science to point to the only planet we know of and then proclaim that life is common in the Universe.
      Right now we have a sample size of one.

      • Michael Cleveland

        The same physical principles operate throughout the universe, so it’s a reasonable assumption that where conditions are right, there will be life. The only question is how common are those conditions? For John C, there’s nothing odd at all that we find no trace of it. We do not have the technology to look that far away for that kind of fine detail. We surmise that there may be life in the seas under the ice on Europa, but we have no way of detecting it (or refuting) from even this relatively small distance. Finding it there when we go would be a pretty good argument for the probable ubiquitousness of life in the Universe at large. Not finding it says only that it is not there. It’s a very large Universe.

      • Jim Foster

        The sample size of one has nothing to do with the inference about life being common in suitable places. What the study shows is that life as we know it can emerge and diversify much more quickly (and therefore probably more readily) under extreme conditions and probably without oxygen as well. Fair bet that since it was done here it has been done elsewhere. This establishes plausibility, not proof, of course.

  • John Thompson

    So the leading theory on the origin of life is that it just occurred out of nowhere – not so different than what religions claim.
    As for taking the one example we have and then trying to suggest that it predicts other places – that’s a sample size of one.
    Who would have any confidence in a poll that just asks one person?

    • Michael Cleveland

      This all derives from another false premise: that life “appeared out of nowhere.” Whether you believe in metaphysical sources or not, life appeared as a result of physical processes that operate under the same rules everywhere in the Universe. The possibility that our sample of one offers singularly unique conditions, alone in all of the cosmos for those processes, is so remote as to be quite fairly discountable.

  • Pantelo

    Dont forget bacteria might visited from outerspace.


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