Radical Study Suggests Life on Earth Arose Twice
- Reference: 0184886722
- News link: https://science.slashdot.org/story/26/08/07/0059221/radical-study-suggests-life-on-earth-arose-twice
- Source link:
> "The surprise is that the enzymes that catalyze those reactions are not conserved across the evolutionary divide that separates bacteria and archaea," [2]says William Martin, a biologist at Heinrich Heine University Dusseldorf in Germany.
>
> "The new data leave only one conclusion. The bacterial and archaeal lineages made the transition to the free-living state independently. Only free-living cells are alive. "Let's call it by name: we are looking at one origin of the genetic code, but two origins of life." That's a huge claim to make, especially when defining what life even is can be surprisingly tricky.
The findings have been [3]published in the journal Science Advances .
[1] https://www.sciencealert.com/radical-study-suggests-life-on-earth-arose-from-non-living-matter-twice
[2] https://www.eurekalert.org/news-releases/1138775?
[3] https://dx.doi.org/10.1126/sciadv.aef3128
Life... uh... finds a way. (Score:3)
Like most of us, life first arose, discovered that it was a really bad idea and went back to sleep.
Living the life (Score:2)
The second arousal is always the best.
Suggests abiogenesis is easy (Score:3)
If this is accurate, this suggests that abiogenesis is easy once one has a stable, watery environment, since it happened twice on Earth. If it was difficult, we'd expect t see it exactly once (it has to happen at least once for us to see it so there's always an anthropic issue there). There was already an argument that we should expect life to be somewhat easy since if not, we'd expect it to have arisen somewhat late on Earth's existence, not soon after. Presumably, one way of seeing if life really is easy is to look at Europa; if we do end up finding life there that will be strong evidence.
Aside from this being cool There is however a worrying bit. One potential conclusion about the Fermi paradox and the apparent the apparent absence of other civilizations in the universe (and not just radio signals, but no visitations, no artifacts, and no sign any civilization in any galaxy is using a major part of its available energy, nor any signs of obvious megastructures in our own galaxy or nearby ones, or things like star lifting [1]https://en.wikipedia.org/wiki/Star_lifting [wikipedia.org], that there is a "Great Filter" [2]https://en.wikipedia.org/wiki/Great_Filter [wikipedia.org] something that makes advanced civilizations very rare. There are two classes of potential filters, early filters, like life arising, multicellular life arising, development of specialized nerve cells, tool use, etc. Then there are late filters, which hit a civilization like nuclear war, bioengineered diseases, bad nanotech, and AI. While late filtering from natural causes is possible it looks unlikely since natural disasters on that scale just aren't that common. Evidence like this means less early filtration, and makes it more likely that there is a genuine Great Filter that we are going to need to pass through.
Personally, I used to be generally skeptical of AI being the Great Filter, because it seemed like if a lot of civilizations were being taken over by AI, we'd see evidence of that as the AIs spread out to the stars. If something spread at anything less than 99% or so of light speed, we'd have a lot of a chance to helplessly see it coming. However, the AIs were producing while dangerous seem less likely than I would have guessed to just take over everything in their future light cone, in part that their goal oriented behavior is limited, and they come across as more pseudominds than true minds with long-term planning and objectives. In that contex, the chance that AIs wipe out civilizations and wipe themselves out in the process or shortly thereafter is looking like a worryingly likely explanation.
[1] https://en.wikipedia.org/wiki/Star_lifting
[2] https://en.wikipedia.org/wiki/Great_Filter
Re: (Score:2)
Maybe this life-arising-twice thing is the early filter.
i.e. Lots of places have life, but only a very few have had it arise twice ( maybe the first prevents the second ) and that very few only got intelligent life because of the two lifeforms merging.
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Interesting discussion but I'm not sure the conclusion is sound. Judging difficulty on a sample size down around one or two isn't great. I could just as easy put out that zero is the number that indicates it's hard. Knowing life arose once suggests it's not "hard". Given the time-spans involved here, it could be very, very unlikely in any meaningful sense but the sheer amount of time allowed it to eventually happen, twice even... while leaving it statistically unlikely.
As for the Fermi's Paradox, I t
Re: (Score:2)
> Interesting discussion but I'm not sure the conclusion is sound. Judging difficulty on a sample size down around one or two isn't great. I could just as easy put out that zero is the number that indicates it's hard. Knowing life arose once suggests it's not "hard". Given the time-spans involved here, it could be very, very unlikely in any meaningful sense but the sheer amount of time allowed it to eventually happen, twice even... while leaving it statistically unlikely.
Life arising once should reduce the chance of life arising separately (or at least taking off after it arises) since you already have life around using a lot of the obvious resources. If life tried to arise again now for example, it would likely be quickly consumed by much more optimized living things. But even putting that aside, if the chances are independent, and the chance of life arising on an Earth-like planet is x, then the chance of it arising twice on the same planet should be x^2 . That means that
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I really like that quote:
> "Sometimes I think we're alone in the universe, and sometimes I think we're not. In either case the idea is quite staggering." -- Arthur C. Clarke.
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While I wholeheartedly agree with your first paragraph, however your AI fears are far less grounded. There may not even be a great filter - especially as we are not anywhere close to being a Type 0 Kardashev. As for late filters, if we want to be clear, the primary concern is runaway *anything* - the point where we have the technology to change the world, but not the foresight to know what the consequences of our actions are. We are definitely in that space. But AI isn't the issue - climate change is the
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> There may not even be a great filter - especially as we are not anywhere close to being a Type 0 Kardashev.
Huh? That's not an argument against a Great Filter. That's an argument to think that we're not near it yet. But it also isn't an argument that works that well. What matters less is being K0 and more being spread out. Once you're multiplanetary (in the genuine sense, not the oh-put a few people there) this goes way up, and we're likely only a few centuries form that at worst.
> climate change is the far larger concern -
Climate change is bad, and we're not doing enough about it. But it isn't a great filter situation. We're unlikely at this point to hit
Re: Suggests abiogenesis is easy (Score:2)
I hear you - and to a point, agree - but where you argue 'not a filter' I counter 'filter risk' - my point was, and remains, we do not demonstrate willingness to be answerable to consequences - and that adds a very high risk to survivability. The ability to get along harmoniously is a necessary cause for remaining at K0 - and that was my prior. Harmony doesn't mean kumbaya happy-clappy - it means recognising that global economics work better when viewed as a non-zero sum.
Re: Suggests abiogenesis is easy (Score:2)
(soz - read necessary cause to exceed K0).
Re: (Score:1)
> If this is accurate, this suggests that abiogenesis is easy once one has a stable, watery environment, since it happened twice on Earth.
That was my first thought too. (Assuming the article is correct - all kinds of stuff gets published that doesn't hold up in the longer run.)
> One potential conclusion about the Fermi paradox [...]
Remember that time is also big. Suppose that there have been 1000 interstellar civilizations in our galaxy during the past 5 billion years, and that each one lasted a million years before collapsing. How many would be active right now?
Frankly, I don't consider it a paradox at all. We've explored approximately 0% of our galaxy and found nothing. That doesn't tell us
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> Remember that time is also big. Suppose that there have been 1000 interstellar civilizations in our galaxy during the past 5 billion years, and that each one lasted a million years before collapsing. How many would be active right now?
That's possible, but the question is how likely is it? If you've gotten to be around for a million years, you've learned a massive amount, you've likely spread to multiple star systems, so you've got all of that. That means a collapse would have to wipe out multiple different parts of your civilization in multiple star systems. And at even a few thousand years, you start getting things like added resilience from terraforming/xenoforming nearby planets. Worst case time estimates for example say it would take
Re: (Score:2)
Chasing after Dyson spheres might be pointless. The resources needed to build one, or even a low density Dyson swarm would tax the resources of a single planet or even the exploitable resources of a solar system. So we wouldn't see one until a civilization had developed interstellar travel. But once they've got that, why bother with the sphere anymore? You just expand your civilization to the newly colonized systems.
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If you want to harness a lot of energy, or you want a really big civilization where everyone can talk with each other, then a Dyson sphere is better. If you spread out to multiple star systems, you have to wait for years between contact. It seems likely that a sufficiently advanced civilization would try both. And the white dwarf Dyson swarms would require much less material, engineering work, etc (probably orders of magnitude less).
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That's actually a pretty good time range - Sun-like stars in the Galactic Habitable Zone have been around for about 9 billion years, and if we assume Earth's 4.5 billion year history is typical, 5 billion years ago is about as far back as you'd expect to find little green men.
We are on the verge of being able to scan the atmosphere of exoplanets in bulk. It won't be that long (relatively speaking) before we'll know if there are any planets in our sky with chemistry that suggests a living biosphere. I hope
Re: Suggests abiogenesis is easy (Score:2)
> While late filtering from natural causes is possible it looks unlikely since natural disasters on that scale just aren't that common.
It is definitely too soon to draw this conclusion, because we have only just entered our first global scale civilization. And we are testing the global humanity carrying capacity.
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We know how common large scale *natural* disasters are. Not very common since the last one was 65 million years ago and the one before that was even longer ago. Disasters which are arise which can kill a civilization are therefore much more likely to be things that we do to ourselves. That doesn't mean we shouldn't be working on things like asteroid deflection of course, but it isn't the most likely scenario. Asteroids aren't out there hunting civilizations.
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"Asteroids aren't out there hunting civilizations."
Arguably -- asteroid collisions delivered crucial sub-units of life to the early rocky earth. The more collisions the more likely were life-supporting collisions ... so planets that "get in the way" of asteroids are more likely to develop life; great for early earth / early life. But, a disaster once life has complexified into "civilizations". Those planets most likely to have asteroid collisions that "start" life are also most likely to have collisio
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This is a good reason to suspect that asteroids are more common on worlds with life. But 65 million years, and millions of years before that show it just isn't that common. For a natural disaster to be the Great Filter it would need to be happening every few hundred years.
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Or it could be that they both evolved from an earlier and different process which was quite inefficient and which was replaced by the 2 mechanisms of bacteria/archea so thoroughly that no genetic trace remains.
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That's a neat and plausible idea. And if that's the case, then the concerns I raised don't really fall out at all.
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At this rate we will end ourselves with AGW before we achieve AGI.
But if not that, it'll be nukes or [1]biotech [slashdot.org].
It's looking increasingly like the great filter is that ambition exceeds ability while ability also exceeds restraint, and at the same time, a species gains the ability to destroy itself. TBF our sample size is small, but it remains compelling...
[1] https://science.slashdot.org/story/26/08/06/1824255/scientists-make-first-viruses-designed-by-ai
Re: (Score:2)
> If this is accurate, this suggests that abiogenesis is easy once one has a stable, watery environment
It obviously takes a bit more than that, but it's probably fair to say that simple life is inevitable when all the necessary pre-conditions are there. Chemistry is going to happen.
The necessary pre-condiitons do include things like an energy source, maybe more than just sunlight, certain rarer chemicals such as phosphorus that earth acquired via asteroid/meterorite impacts. For complex life a metallic c
I'm holding out for silicon based life... (Score:2)
...and hot green alien chicks.
That makes sense (Score:2)
The bacteria obviously went barbarian class, whereas the archaea went mana usage for magic. Since we don't have any spellcasters anymore, this tracks logically.
Truly radical, or by accepted dogma? (Score:1)
The accepted dogma of so many 'scientific' explanations is hesitant to even accept that our knowledge and understanding may have evolved. What we once thought was true may not be. But established dogma digs in its heels... Look at COVID. The powers that be were unwilling to admit 'we do not know, yet,' and the narrative changed multiple times within the same week. That bred distrust and split people along political party lines. Science can be bought. Results can be skewed, fabricated.
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> What we once thought was true may not be. But established dogma digs in its heels... Look at COVID. The powers that be were unwilling to admit 'we do not know, yet,' and the narrative changed multiple times within the same week. That bred distrust and split people along political party lines.
I was paying a lot of attention to what the actual medical scientists were saying at the time, and they were saying "we don't know. Here's our best guess at the moment" over and over and over .
But people were desperate to hear definite conclusions, not "here's what we think so far." If you think you were hearing "here are things we know for sure," that was you ignoring the part where reports say things like "if confirmed, this result means..." or "According to senior scientist x, further work is needed to
Re: (Score:2)
> The accepted dogma of so many 'scientific' explanations is hesitant to even accept that our knowledge and understanding may have evolved. What we once thought was true may not be. But established dogma digs in its heels...
> Look at COVID. The powers that be were unwilling to admit 'we do not know, yet,' and the narrative changed multiple times within the same week. That bred distrust and split people along political party lines.
> Science can be bought. Results can be skewed, fabricated.
I bet your TV is broken and has only one channel. Fox News. You should get that fixed.
Bad overly-dramatic summary (Score:2)
This summary of "life evolved twice" is just click-bait.
The article it is referring to has the much more sober title of "Intermediate stages in the origin of metabolism at a
phosphorylating hydrothermal vent".
This doesn't change the understanding of LUCA as a single last universal common ancestor cell that gave rise to LACA (last archea common ancestor) and LBCA (last bacteria common ancestor).
What the article is saying is that the metabolism of LUCA was "incomplete" and not yet self-contained, still relying
If Life Arose Twice... (Score:1)
...does that mean there's a chance intelligent life has the chance to make a second coming?
Re: (Score:2)
Only this fall's election will settle that question.
But...they share the same DNA building blocks (Score:2)
If two types of living organisms developed completely independently, what are the chances they would both share the same exact ACTG building blocks of DNA?
We know that ACTG is not the only combination of chemicals that are able to form the reproductive backbone of life. For example, when pharmaceutical companies developed MRNA COVID vaccines, they substituted natural uridine with a modified version (N1-methylpseudouridine) in the RNA strands, in order to evade the body's immune responses. The replacement mo
Ancient Astronaut theorists (Score:2)
I came here for ancient astronaut theories only, so disappointed.
Ahem. (Score:2)
. . . Figured it out . . .
Grrrrr . . .
I'd be surprised if its only 2 (Score:5, Interesting)
A chemical system that can reproduce via a stored code and copy that code is the hard part of life , wrapping it inside some sort of bubble its probably relatively simple, and given how small cells are and how large the earth is I wouldn't be surprised if once genetics got going it happened multiple times but only 2 lineages made it through.
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> A chemical system that can reproduce via a stored code and copy that code is the hard part of life , wrapping it inside some sort of bubble its probably relatively simple, and given how small cells are and how large the earth is I wouldn't be surprised if once genetics got going it happened multiple times but only 2 lineages made it through.
I was just about to say the same thing. I would not be surprised if new forms of life arise even now in the benthic environment. Probably not successful, but possibly.
The whole thing about not being able to define life, FTA, is partially, the moving goalposts regarding human created life, and the desire by some to heavily categorize things.
That's how virus' are not considered life even though they evolve, reacting to their environment, and reproduce. They rely on other life to metabolize. Perhaps we've
Re: (Score:2)
Unfortunately the word "life" is a rather catch all term for what in reality is a range of processes and "what is life" is more a venn diagram than a hard definition. Maybe life requires A, B, C or B,C,D or A,D,E but doesn't need all of them at any one time to consider "alive".
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The question even becomes "what is life".
It's believed life started because two molecules got closer together and then bonded. Those two molecules being proto-DNA then developed the capability to reproduce itself. But we're far from cellular life as we would consider it - just a primordial soup of stuff and two proto-DNA molecules coming together and then being to reproduce a copy of itself.
Re: (Score:2)
arise even now in the benthic environment
*twitches uncomfortably, having read Peter Watts' Rifters trilogy*
Re: (Score:2)
>> arise even now in the benthic environment
> *twitches uncomfortably, having read Peter Watts' Rifters trilogy*
I haven't read it, but the outlines are a little disturbing.
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Agreed; the spans of time are so vast as to be incomprehensible. Looked at it that way, it would be hard to believe that if there ARE other pathways to "life", that pretty nearly all of them hadn't been explored, and even if failed, explored repeatedly later.
4.6 Billion Years Ago: Earth forms from cosmic dust and rock.
3.8 to 3.7 Billion Years Ago: First single-celled organisms (prokaryotes) and microbial life appear in the oceans.
2.4 Billion Years Ago: Cyanobacteria develop photosynthesis, releasing oxygen