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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

#61

Post by pfdietz »

ck2 wrote: post #59
pfdietz wrote: post #55

Earlier quoted context omitted.

"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)

Sorry, when you make an assertion, you don't get to demand I justify questioning it. You need to explain why I should believe you.

Your reversal of burden of proof is a red flag that you don't have a good argument.

IMO, it is quite plausible that OoL is extremely unlikely and that our solar system is the only place where life occurs in the visible universe. Not proved, of course, but the possibility is by no means unreasonable.

Re: Radical Study Suggests Life on Earth Arose Twice

#62

Post by NoMoreNicksLeft »

If life could arise once, why would the conditions not be amenable to it arising more than once? Sure, life tends to pollute-terraform for itself, but it's a big planet, with more than enough distance between the first occurrence and pristine environment for it to happen several more times.

Re: Radical Study Suggests Life on Earth Arose Twice

#63

Post by NoMoreNicksLeft »

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…

>ike availability of water, temperatures, etc. We should see a constant emergence of new life all the time. Why would that process stop,

Anything that's so agreeable to abiogenesis that life might spontaneously manifest, is actually pretty tasty for things already alive. They swoop in and eat it before it gets started. So, I suspect that even what the article says isn't that they both arose in the same place, but in different places separated by distance, time, and/or environmental barriers.

Re: Radical Study Suggests Life on Earth Arose Twice

#64

Post by tejtm »

altcognito wrote: post #38
binaryturtle wrote: post #36

Earlier quoted context omitted.

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…

It has to survive though in the sense that it has to live long enough for us to see it. If we think of life as "spontaneously" (roughly speaking) emerging from the right conditions reasonably rarely, it has to outcompete other existing life for some time. And then there's the chance that we might not recognize it as "new" at all.

A step further "novel" life (hence still simpler) made from the same raw materials as existing life would look exactly like decomposing existing life and be routinely scavenged for material.

Re: Radical Study Suggests Life on Earth Arose Twice

#66

Post by wwarner »

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.

Maybe, or maybe it was eaten into extinction.

Re: Radical Study Suggests Life on Earth Arose Twice

#67

Post by EA-3167 »

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.

Geology over large time-scales is profoundly unforgiving.

Re: Radical Study Suggests Life on Earth Arose Twice

#68

Post by AngryData »

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…

But the enviroments that have the easy/free energy that would give rise to life is almost always contaminated with life competing for and consuming that chemical energy.

Re: Radical Study Suggests Life on Earth Arose Twice

#69

Post by culi »

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.

Coacervates, liposomes, acetogenic precursors, etc are all commonplace and could be considered proto-life. Some scientists have even argued that viruses are proto life. Prions (misfolded proteins that can self-replicate) and plasmids (non-chromosomal DNA strands that play a major role in horizontal gene transfer) are also candidates for proto-life that blur the line between living and non-living

Re: Radical Study Suggests Life on Earth Arose Twice

#70

Post by giantrobot »

Drakim wrote: post #35
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.

Hash competition from life might cause them to go extinct, and even if it happens again it just gets out-competed to extinction fast.

It could be happening on my kitchen counter right this very second. But my kitchen counter, despite a recent cleaning, is absolutely lousy with microorganisms. So the new proto-life is immediately starved or more likely eaten by existing life. There's very few places on Earth that has not been colonized by some sort of life so there's very few places a new form of life could form and succeed long enough to itself grow and spread without being starved or eaten.
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