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littlebird
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How does non-life evolve into life ?
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PickyPicky
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Here on Earth? Excellent question. And a Nobel Prize for the first correct answer (because science — and I take it you are looking for a scientific answer — doesn’t yet know).
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ATraveller
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I wouldn’t say ‘evolve’ at that point.
It’s very complex and all the conditions have to be right. You need to have all the right precursor molecules to be present, possibly in a specific range of concentrations and relative to each other. An adequate amount of energy would also be required to allow the molecules to react with one another. Reactions to form DNA, which serve as templates to synthesise a variety of proteins that have different functions and reactions to provide energy for the organism to function and for further reactions.
For that life form to continue to exist and not die off, it would have to have the ability to reproduce. The ability to have the genes to synthesise a whole plethora of proteins required to split the DNA in reproduction, place genetic bases in the right locations when producing new strands of DNA, protect the DNA from other reactions during reproduction, replace incorrect bases in copying errors and then to stop the reproduction process.
Things get more complicated when hormones, immune systems, tissues and organs are thrown in. And intelligence and self-awareness are much more complex.
I find it very difficult to believe we’re just a big cosmic accident.
It’s very complex and all the conditions have to be right. You need to have all the right precursor molecules to be present, possibly in a specific range of concentrations and relative to each other. An adequate amount of energy would also be required to allow the molecules to react with one another. Reactions to form DNA, which serve as templates to synthesise a variety of proteins that have different functions and reactions to provide energy for the organism to function and for further reactions.
For that life form to continue to exist and not die off, it would have to have the ability to reproduce. The ability to have the genes to synthesise a whole plethora of proteins required to split the DNA in reproduction, place genetic bases in the right locations when producing new strands of DNA, protect the DNA from other reactions during reproduction, replace incorrect bases in copying errors and then to stop the reproduction process.
Things get more complicated when hormones, immune systems, tissues and organs are thrown in. And intelligence and self-awareness are much more complex.
I find it very difficult to believe we’re just a big cosmic accident.
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rossum
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Correct. Evolution only starts after the appearance of the first life. Before that was the chemistry of abiogenesis.
Experiments to date have shown that amino acids, purines, pyrimidines and lipid bilayers can all form under prebiotic conditions on the early earth.
There are various ideas as to what the first very simple life looked like. Almost all of them agree that DNA was not present at the very start, it appeared later. One of the possible ideas is the RNA World where RNA alone performed the functions of both DNA (information storage) and proteins/enzymes (catalyzing chemical reactions). There are other possible ideas as well, abiogenesis is still a work in progress.
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Rhubarb
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It’s been demonstrated that the very fundamental building blocks of life can be synthesized. Even RNA strands that can build protein molecules.
Given the absolutely cosmic scale of the universe, and billions of years to do it, the laws of probability are in favor of somewhere, at some time, the conditions will be right that these molecules that form hit each other, or otherwise combine. In much the same way that monkeys banging on typewriters will eventually bang out Shakespeare if given enough time. A virus, and plasmids, while not life by our current paradigm, are pretty simple things. And considering what we know about early bacteria I don’t see it as a huge impossible step to go from something like a plasmid to a simple prokaryote cell, and from there eventually to a eukaryote.
Remember that the Earth isn’t a closed system. It is constantly having energy and occasionally matter introduced to the system. I’m not a physicist but conceptually, so long as energy is being added a system doesn’t have to decay into entropic death. So long as an engine is running, life can play the waiting game until just the right combination of circumstances converge to bloom.
And, at least when I speak to people face-to-face, they’re always saying things like “how do we go from an amoeba to a fish? That makes no sense!!” But to me that shows that they’re not truly grasping the vast and huge timespans that are in play. The ladder isn’t "plasmid->Bacteria->Fish. It’s a chain billions of organisms long. I mean, the only difference between a prokaryote and eukaryote is that the more “advanced” eukaryote has an enclosed nucleus, and other organelles like a mitochondria. The prokaryote has everything just floating freely within the cell membrane. All it would theoretically take is for some very basic cellular structures - namely a single molecule of DNA and a few ribosomes, to be encapsulated by a membrane. Boom, you’ve got a primitive cell. And conceptually all you would need is for a prokaryote to turn into a eukaryote is absorb the remaining organelles it needs - which is precisely how biologists think the mitochondria came about because of mitochondrial DNA. It’s not far fetched because we see bacteria exchanging genetic information through plasmids. We’ve observed that in labs today so we know cells can transfer material back and forth.
However we haven’t seen this occur directly. (Science doesn’t demand direct observation like that, I don’t know why people think that. We’ve never directly observed an atom but we still know a lot about them) We don’t have a master sheet of life’s pedigree. There’s no way to say that what I’ve described is EXACTLY what happened. But it seems plausible to me, at least, that abiogenesis is possible. And not only that, when you factor in the billions of years the planet has had, it might even be probable.
Given the absolutely cosmic scale of the universe, and billions of years to do it, the laws of probability are in favor of somewhere, at some time, the conditions will be right that these molecules that form hit each other, or otherwise combine. In much the same way that monkeys banging on typewriters will eventually bang out Shakespeare if given enough time. A virus, and plasmids, while not life by our current paradigm, are pretty simple things. And considering what we know about early bacteria I don’t see it as a huge impossible step to go from something like a plasmid to a simple prokaryote cell, and from there eventually to a eukaryote.
Remember that the Earth isn’t a closed system. It is constantly having energy and occasionally matter introduced to the system. I’m not a physicist but conceptually, so long as energy is being added a system doesn’t have to decay into entropic death. So long as an engine is running, life can play the waiting game until just the right combination of circumstances converge to bloom.
And, at least when I speak to people face-to-face, they’re always saying things like “how do we go from an amoeba to a fish? That makes no sense!!” But to me that shows that they’re not truly grasping the vast and huge timespans that are in play. The ladder isn’t "plasmid->Bacteria->Fish. It’s a chain billions of organisms long. I mean, the only difference between a prokaryote and eukaryote is that the more “advanced” eukaryote has an enclosed nucleus, and other organelles like a mitochondria. The prokaryote has everything just floating freely within the cell membrane. All it would theoretically take is for some very basic cellular structures - namely a single molecule of DNA and a few ribosomes, to be encapsulated by a membrane. Boom, you’ve got a primitive cell. And conceptually all you would need is for a prokaryote to turn into a eukaryote is absorb the remaining organelles it needs - which is precisely how biologists think the mitochondria came about because of mitochondrial DNA. It’s not far fetched because we see bacteria exchanging genetic information through plasmids. We’ve observed that in labs today so we know cells can transfer material back and forth.
However we haven’t seen this occur directly. (Science doesn’t demand direct observation like that, I don’t know why people think that. We’ve never directly observed an atom but we still know a lot about them) We don’t have a master sheet of life’s pedigree. There’s no way to say that what I’ve described is EXACTLY what happened. But it seems plausible to me, at least, that abiogenesis is possible. And not only that, when you factor in the billions of years the planet has had, it might even be probable.
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rossum
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You don’t need the DNA. RNA alone can act as information storage and as a catalyst: see ribozyme.
And at one time, mitochondria were free-living prokaryotes before setting up a symbiosis with the first eukaryotes. They even have the remnants of their own original DNA on board still.
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benjamin1973
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It’s not really an answer to your question. But here’s my take on it: the Universe might be more alive than we normally think. Experiments in quantum physics (look up double-slit experiments and especially “quantum eraser”) show that the Universe interacts with us in ways that seem to involve foreknowledge of events, or that the Universe can change how it behaves in response to our actions.
In other words, it may be that everything around us is “alive” in a sense, and that the apparent emergence of say a collection of amino acids into an organism is just an arbitrary line in the sand that we draw based on our own world view of what life is or isn’t.
In other words, it may be that everything around us is “alive” in a sense, and that the apparent emergence of say a collection of amino acids into an organism is just an arbitrary line in the sand that we draw based on our own world view of what life is or isn’t.
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littlebird
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Yeah…No scientific ability to create life from non-life. Lots of good theories though !
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HerCrazierHalf
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Imo this is just one of the great unknowns. Perhaps it is unknowable and that’s fine by me.
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ATraveller
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That’s interesting. I knew that was generally the case for retroviruses and that RNA is more vulnerable to nucleophilic reactions than DNA.
This maybe relevant to the topic (credit goes to @TK421 for sharing this in a different thread):
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RandomAlias
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I watched that video in the other thread, and it is an interesting account of some of the improbable events leading to the evolution of man. An objection that occurs to me is that there are many other improbable series of events that could have led to intelligent life and which we haven’t accounted for.
Let’s assume, for the sake of discussion, that on Earth there were millions of different pathways, all highly improbable, by which some kind of intelligent life could have formed. One of them worked, leading to man, but if it hadn’t worked, eventually another path may have led to some other (non-human) intelligent life on Earth. Or maybe it wouldn’t have, because the probabilities are just too low.
Further assume that there are a billion other planets harboring life, and each has its own millions of different improbable pathways to intelligent life. If only one pathway on one planet succeeds, then we are not alone. The improbability of one pathway – ours – doesn’t imply the probability of all other pathways failing.
Let’s assume, for the sake of discussion, that on Earth there were millions of different pathways, all highly improbable, by which some kind of intelligent life could have formed. One of them worked, leading to man, but if it hadn’t worked, eventually another path may have led to some other (non-human) intelligent life on Earth. Or maybe it wouldn’t have, because the probabilities are just too low.
Further assume that there are a billion other planets harboring life, and each has its own millions of different improbable pathways to intelligent life. If only one pathway on one planet succeeds, then we are not alone. The improbability of one pathway – ours – doesn’t imply the probability of all other pathways failing.
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Hope_Philomena
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You’re giving me flashbacks to my AP Biology test
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Hope_Philomena
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Didn’t the Miller-Urey experiment get pretty close? I can’t recall exactly. In class we are taught that the Miller-Urey experiment pretty much explained abiogenesis, at least to an extent.
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RandomAlias
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Not even close. They got amino acids, which was great. Didn’t they win a Nobel Prize? But life requires so much more.
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Rhubarb
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It demonstrated that it is possible. Not that it definitely happened that way, but that indeed necessary molecules could form.
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Rhubarb
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Further experiments after have shown that DNA and RNA nucleobases can be created in abiotic atmosphere.
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RandomAlias
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Oh yeah, I think I was aware of that but had forgotten. Nucleobases get us a step or two closer. There are still a few more hard steps before life emerges.
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ChunkMonk
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It doesn’t. But don’t let that stop anyone from telling you they’re smart because they agree with the right things, regardless of what they know or don’t know about it.
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Kei
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Those saying that this wouldn’t be evolution have clearly no idea of the idea that energy is the first life (this is a real thing)!
People like to say we’ve gotten so far, but in truth we have yet much to go. Still no manmade life, even with intelligent humans working on it.
People like to say we’ve gotten so far, but in truth we have yet much to go. Still no manmade life, even with intelligent humans working on it.
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Glark
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You were lied to by atheist propaganda. Scientists these days don’t consider the Miller-Urey to be evidence that natural abiogenesis is possible. Besides a few useless amino acids, the experiments also produced great globs of highly toxic “black stuff” that is lethal to life.
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