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Radical Study Suggests Life on Earth Arose Twice

sciencealert.com

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Re: Radical Study Suggests Life on Earth Arose Twice

#51

Post by RetroTechie »

binaryturtle wrote: post #36
mycall wrote: post #34

Earlier quoted context omitted.

You would think there would be some isolated places where proto-life still exists for this to be true.

I always found it odd that there's only one single origin of life point or even just a single common ancestor considered in history. Shouldn't entirely new life develop all the time on earth? I mean the ingredients and building blocks are still there, the environmental situation still should work out, like availability of water, temperatures, etc. We should see a constant emergence of new life all the time. Why would…

> Maybe we just can't detect this

Probably this. How would we know what such 'proto-life' (perhaps even just some self-replicating soup of chemicals, no cell wall) would look like? Where to find it? How rare its occurence? Etc etc.

Scientists might not even recognise it if happened right in front of them.

I'd put my money on coming up with a more general definition of "life", and then looking for short(est) pathways from "soup of random chemicals" to "something in there that replicates (parts of) itself".

Doesn't need to look like life as we know it, as long as some elements of "self-organising structures, something being replicated" are there.

Re: Radical Study Suggests Life on Earth Arose Twice

#52

Post by prewett »

TacticalCoder wrote: post #12
theodorejb wrote: post #5

[flagged]

> As I see it life was clearly designed by God. Which one? There are so many to choose from... And what created that God? I know it's turtles all the way down but still want to know.

I believe that according to Catholic and Orthodox thought, God is Being itself. If you're familiar with Plato and Aristotle, God is the Form of Being. If not, I guess you could say God is Being as a noun, or God is where the idea of Being comes from. God exists because he is existence itself. (He is also Life and Love, in the same way)

Re: Radical Study Suggests Life on Earth Arose Twice

#53

Post by Qem »

pfdietz wrote: post #47
Qem wrote: post #27

Earlier quoted context omitted.

Likely we don't need to replicate. We just need to get a sample of life with completely independent origin to our kind of life here on Earth, to study. This way we would be able to separate what are universal properties for any life from historical contingencies specific to us. To have samples of a single kind of life complicates things.

Were that to happen it could be the worst news humanity ever receives, since it would greatly increase the chance the "Great Filter" is in front of us, not behind us.

Not if it's just microbial life. Anyway it's just one case or another. We knowing what's the case doesn't change it. If the news never break it would be just as bad, perhaps even slightly worse, as we would not have early warning to prepare.

Re: Radical Study Suggests Life on Earth Arose Twice

#54

Post by ck2 »

pfdietz wrote: post #50
ck2 wrote: post #29

Earlier quoted context omitted.

There is likely simple basic life as advanced as bacteria around the universe But high level life was likely a series of complex accidents that is not reproducible or would be radically different than us One of my absolute favorite PBS Space Time on the subject * https://www.youtube.com/watch?v=abvzkSJEhKk

> There is likely simple basic life as advanced as bacteria around the universe What is the basis for this assertion?

single-cell "life" can be so simple that scientists can create it in a lab "SpudCell"

* https://www.science.org/content/article/lab-created-spudcell...

somewhere among 2 TRILLION planets in our galaxy there is a planet with enough atmosphere and magnetosphere to protect it from space radiation so there is likely bacteria

but complex life far more difficult and unlikely, very rare, as explained in the PBS Space Time I linked above, the "Cambrian Explosion"

* https://en.wikipedia.org/wiki/Cambrian_explosion

if there are viruses and fungi out there however, they could mutate eventually with enough permutations and outside stressors

that video explains the huge leap forward with DNA vs simple protein patterns

Re: Radical Study Suggests Life on Earth Arose Twice

#55

Post by pfdietz »

ck2 wrote: post #54
pfdietz wrote: post #50

Earlier quoted context omitted.

> There is likely simple basic life as advanced as bacteria around the universe What is the basis for this assertion?

single-cell "life" can be so simple that scientists can create it in a lab "SpudCell" * https://www.science.org/content/article/lab-created-spudcell... somewhere among 2 TRILLION planets in our galaxy there is a planet with enough atmosphere and magnetosphere to protect it from space radiation so there is likely bacteria but complex life far more difficult and unlikely, very rare, as explained in the PBS Space Time I…

"SpudCell" already has 36 genes; the information encoded there basically cannot occur by random processes. There is still an enormous complexity gap between it and abiotic systems.

> somewhere among 2 TRILLION planets in our galaxy there is a planet with enough atmosphere and magnetosphere to protect it from space radiation so there is likely bacteria

I reject this conclusion; it certainly isn't justified by the links you provided.

Re: Radical Study Suggests Life on Earth Arose Twice

#56

Post by jnwatson »

ch4s3 wrote: post #6
lanstin wrote: post #3

Earlier quoted context omitted.

They aren’t saying two totally different independent life creating event, they are saying that the earliest life depending on some external chemicals for parts of what is now covered by metabolism, and the tree of life diverged before those metabolic paths evolved inside the organism, so not totally the same emergence of life twice, but more stuff that reproduces and evolves but doesn’t meet modern standard for life.

The science alert article should make this more clear, as its easy to get that impression.

The article does make it clear, though the headline misleads.

Re: Radical Study Suggests Life on Earth Arose Twice

#57

Post by randomImmigrant »

mycall wrote: post #34
randomImmigrant wrote: post #25

The metabolic science is really cool. The conclusion that life arose twice requires you to buy that proto-cells that grew on these vents and needed those metallic surfaces to survive didn’t count as “life”. Then, free living cells, bacteria and archea, could maybe be argued as having independent paths as they plugged the gaps in their metabolism independently. Same DNA/RNA, same proteins. Same broad rules of metaboli…

You would think there would be some isolated places where proto-life still exists for this to be true.

No, because conditions have changed markedly. For metals to act as catalysts, and replace some metabolic enzymes, they need to be in highly reduced conditions. This was true in early Earth, but about 2.5 billion years ago, we had the great oxygenation event, and over the next billion years free oxygen has gone up enough that you won’t find the reduced conditions where metal can take over the job of metabolic enzymes in much of Earth anymore.

That is, what sustains today’s life prevents new proto-life for forming. You need to have the fancy gadgets life has today to continue to survive and replicate on Earth.

Note though, it was other life forms that contributed to the great oxygenation event, too. This is all a continuous web.

Re: Radical Study Suggests Life on Earth Arose Twice

#58

Post by randomImmigrant »

binaryturtle wrote: post #36
mycall wrote: post #34

Earlier quoted context omitted.

You would think there would be some isolated places where proto-life still exists for this to be true.

I always found it odd that there's only one single origin of life point or even just a single common ancestor considered in history. Shouldn't entirely new life develop all the time on earth? I mean the ingredients and building blocks are still there, the environmental situation still should work out, like availability of water, temperatures, etc. We should see a constant emergence of new life all the time. Why would…

The ingredients and building blocks aren’t there in the same way. Because life formed, those early ingredients are now transformed, as is the environment. This blocks new life of the type that formed 4 billion years ago from forming again.

Indeed, all species branch out from that one universal common ancestor that was the first free living successful cell.

Put another way: forming life isn’t easy at all. And once it forms it changes conditions to suit its continuation, not to allow new life to form.

Re: Radical Study Suggests Life on Earth Arose Twice

#59

Post by ck2 »

pfdietz wrote: post #55
ck2 wrote: post #54

Earlier quoted context omitted.

single-cell "life" can be so simple that scientists can create it in a lab "SpudCell" * https://www.science.org/content/article/lab-created-spudcell... somewhere among 2 TRILLION planets in our galaxy there is a planet with enough atmosphere and magnetosphere to protect it from space radiation so there is likely bacteria but complex life far more difficult and unlikely, very rare, as explained in the PBS Space Time I…

"SpudCell" already has 36 genes; the information encoded there basically cannot occur by random processes. There is still an enormous complexity gap between it and abiotic systems. > somewhere among 2 TRILLION planets in our galaxy there is a planet with enough atmosphere and magnetosphere to protect it from space radiation so there is likely bacteria I reject this conclusion; it certainly isn't justified by the link…

you don't think there is even single-cell life anywhere else but Earth?

why would Earth be that incredibly unique?

it's even plausible Earth was accidentally seeded by panspermia (bacteria on comets)

Re: Radical Study Suggests Life on Earth Arose Twice

#60

Post by ahazred8ta »

binaryturtle wrote: post #36
mycall wrote: post #34

Earlier quoted context omitted.

You would think there would be some isolated places where proto-life still exists for this to be true.

I always found it odd that there's only one single origin of life point or even just a single common ancestor considered in history. Shouldn't entirely new life develop all the time on earth? I mean the ingredients and building blocks are still there, the environmental situation still should work out, like availability of water, temperatures, etc. We should see a constant emergence of new life all the time. Why would…

They're pretty sure the primordial environment was a hydrothermal vent in an anoxic high phosphorus soda lake with methane, ammonia, and UV exposure. Nowadays those lakes don't have the methane and ammonia, so that environment isn't there anymore. https://www.science.org/content/article/unusual-soda-lakes-m...

The surfaces of clay particles in these lakes have been dubbed "the primordial sandwich".

The early protocells were 'alive', they were self-replicating, but they required nutrients and metabolic processes that only existed near mineral surfaces and would starve if they drifted away. They had to evolve new enzymes to become 'free-living'.

So it looks like the LUCA was one of these early protocells with an incomplete metabolism.

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