I have wondered for a long time, how did life on earth start? The central dogma of biology is that a living cell arises from a living cell... so how did the first one happen? I recall one experiment where somebody basically created lots of lightning in a small ocean-like system and ended up creating amino acids, but that's still a far cry from life as we know it. I personally believe that God created all life, but I also suspect that God usually works through scientific means. What are your thoughts and knowledge on this?
Also, in debating this topic, EVOLUTION has no place here. I don't care how the first cell grew up and differentiated and became all the species; I want to know what led up to the first cell existing and replicating.
I'm curious why it's important to know the answer of how the first one happened.
That's sort of like asking who shot me with this poison arrow. I don't see how tracing the origin of life to the beginning will change the fact we live in this world that we occupy.
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~~~~~
The short answer is that we don't know. The problem is not that we don't have theories. We have lots of theories. The problem is that whatever happened happened very long ago over a very long time frame, at a scale far too small and delicate to leave evidence which could last so long for us to discover. So we don't currently know of any good way of testing our theories; we can't say that one theory or another did or did not happen.
We can be pretty certain, though, that you're asking the wrong specific question. The first life would not have been a cell. Even a prokaryotic cell is a complex and adaptive structure that would have had to evolve over time. The leading suspects for "first life" are much simpler - either protein or RNA chains. Once you've got one of these self-replicating molecules, evolution is pretty much inevitable.
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We can be pretty certain, though, that you're asking the wrong specific question. The first life would not have been a cell. Even a prokaryotic cell is a complex and adaptive structure that would have had to evolve over time. The leading suspects for "first life" are much simpler - either protein or RNA chains. Once you've got one of these self-replicating molecules, evolution is pretty much inevitable.
I believe its called biopsies, the natural process of life arising from inorganic matter. Both inorganic and organic molecules form naturally under the right conditions. Their are many theories of ground zero for these events to occur such as methane vents in earths early oceans to interstellar dust clouds that meteorites passed through and later collided with earth. Regardless of how simplistic early life was it had to survive the harshest conditions imaginable so IMO only makes sense to look there. Tardigrades are also an organism that can survive the vacuum of space one might wonder where they came from.
We can be pretty certain, though, that you're asking the wrong specific question. The first life would not have been a cell. Even a prokaryotic cell is a complex and adaptive structure that would have had to evolve over time. The leading suspects for "first life" are much simpler - either protein or RNA chains. Once you've got one of these self-replicating molecules, evolution is pretty much inevitable.
You're right, life would have started even before a cell. And when one of those self-replicating proteins or RNA happened inside a somewhat protective membrane, it would have been much more suited to survive and replicate even more than all the "naked" ones. In that case, they would need to have happened a lot on primordial earth to allow for survival of the fittest. If they still happen today, they are probably rare and quickly eaten by passing microbes.
We can be pretty certain, though, that you're asking the wrong specific question. The first life would not have been a cell. Even a prokaryotic cell is a complex and adaptive structure that would have had to evolve over time. The leading suspects for "first life" are much simpler - either protein or RNA chains. Once you've got one of these self-replicating molecules, evolution is pretty much inevitable.
So like a virus then?
Viruses, as we know them today, are obligate intracellular parasites, meaning they can't self-replicate. However, I wouldn't be terribly surprised (given our current speculation) if the first life-form was replicative RNA in a protein shell.
I believe its called biopsies, the natural process of life arising from inorganic matter. Both inorganic and organic molecules form naturally under the right conditions. Their are many theories of ground zero for these events to occur such as methane vents in earths early oceans to interstellar dust clouds that meteorites passed through and later collided with earth. Regardless of how simplistic early life was it had to survive the harshest conditions imaginable so IMO only makes sense to look there. Tardigrades are also an organism that can survive the vacuum of space one might wonder where they came from.
Abiogenesis, or biopoiesis, yeah. That's what Blinking Spirit linked. I've never heard of tardigrades before... that's really cool!
Thank you all for your comments so far. It's only been 4 hours but I know a lot more now than I did 5 hours ago.
Blinking spirit is pretty much right. As far as I know, the currently most accepted hypothesis is that it most likely started as self-replicating RNA strings near thermal vents on the ocean floor. Under the conditions there (temperature, the rock formations which can catalyse RNA-polymerisation), it is possible for RNA to self-assemble. Furthermore, there are some interesting theories about thermal pockets in cavities in the rocks which would've allowed for locally much higher concentrations of these molecules, which makes this process much more likely. And since these things self-replicate, they're under evolutionary pressure.
The mains issues with this theory at the moment is that there is a mathematical limit to the amount of information a mutating, self-replicating string can hold. Hogeweg, among others, has been doing some interesting research in how these early 'organisms' could overcome this information threshold, but it's still very theoretical.
There are some other fun theories, however. One of those was offered by Arthur C Clarke, who noted that life may have a cosmic instead of an earthly orbit. Scientists had noted that all of our satellites were covered in a thin layer of fecal matter, due to the sanitation practices of astronauts. He posited that if other races had the same issues, life may have been brought to earth that way.
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There are some other fun theories, however. One of those was offered by Arthur C Clarke, who noted that life may have a cosmic instead of an earthly orbit. Scientists had noted that all of our satellites were covered in a thin layer of fecal matter, due to the sanitation practices of astronauts. He posited that if other races had the same issues, life may have been brought to earth that way.
Imagine Europa inhabited by descendants of anthropophilic E. coli.
The big problem of this question is evolution sensu lato. Natural selection will eliminate intermediates between basic precursors that can come to be quite spontaneously on a short time scale (e.g. amino acids) and complex developments after years of competitive interactions. It's like trying to understand the total synthesis of a complex organic molecule with just the simple building blocks and the final product known. That there will be multiple pathways possible is only making it worse.
Eh, yeah, it is an issue. However, we don't need to know the precise pathway. We'd like to know the general strokes of how life originated on this planet.
I'm curious why it's important to know the answer of how the first one happened.
That's sort of like asking who shot me with this poison arrow. I don't see how tracing the origin of life to the beginning will change the fact we live in this world that we occupy.
That simile is about as relevant here as a clown-cart.
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We have laboured long to build a heaven, only to find it populated with horrors.
There are some other fun theories, however. One of those was offered by Arthur C Clarke, who noted that life may have a cosmic instead of an earthly orbit. Scientists had noted that all of our satellites were covered in a thin layer of fecal matter, due to the sanitation practices of astronauts. He posited that if other races had the same issues, life may have been brought to earth that way.
The obvious problem with panspermia theories is that they just defer the question. Even if life fell to Earth rather than originating here, it still had to originate somewhere.
Not directly related to abiogenesis, but cool nonetheless, is the hypothesis that life did fall to Earth... after being ejected from Earth. The story goes that at some points during Earth's early history, in particular during the Late Heavy Bombardment, conditions were so bad that life had a better chance surviving in the vacuum of space than down here. So the debris thrown into orbit by the impacts functioned like arks for our earliest macromolecular forebears, falling back down to restart the process once things had cooled down a bit.
That simile is about as relevant here as a clown-cart.
Also, the Buddha was just plain wrong there. My fundamental critique of Buddhism is that he didn't question the assumption that reincarnation occurs, upon which the whole philosophical edifice is premised.
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There are some other fun theories, however. One of those was offered by Arthur C Clarke, who noted that life may have a cosmic instead of an earthly orbit. Scientists had noted that all of our satellites were covered in a thin layer of fecal matter, due to the sanitation practices of astronauts. He posited that if other races had the same issues, life may have been brought to earth that way.
The obvious problem with panspermia theories is that they just defer the question. Even if life fell to Earth rather than originating here, it still had to originate somewhere.
Eh, true, but it's a completely viable answer to the question "where does life on earth come from".
Not directly related to abiogenesis, but cool nonetheless, is the hypothesis that life did fall to Earth... after being ejected from Earth. The story goes that at some points during Earth's early history, in particular during the Late Heavy Bombardment, conditions were so bad that life had a better chance surviving in the vacuum of space than down here. So the debris thrown into orbit by the impacts functioned like arks for our earliest macromolecular forebears, falling back down to restart the process once things had cooled down a bit.
That's a pretty cool hypothesis. I never heard it before, but it explains the almost over-designed nature of bacterial spores.
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The mains issues with this theory at the moment is that there is a mathematical limit to the amount of information a mutating, self-replicating string can hold.
Could you elaborate on what you mean by "information"?
The mains issues with this theory at the moment is that there is a mathematical limit to the amount of information a mutating, self-replicating string can hold.
Could you elaborate on what you mean by "information"?
A DNA string is not so different from a binary string from an information point of view: the longer it is, the more information it can contain. The issue is that at some mutation rate, even the best sequence is no longer able to replicate itself with enough precision to sustain itself. This mutation rate is called the information threshold (or error threshold). Shuster and Eigen did a lot of work on this.
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I knew that the moment you said 'the central dogma of biology.' Whenever I see someone that resents the study of God's creation (such as biology, geology, or astronomy), it's always a christian.
I have wondered for a long time, how did life on earth start? The central dogma of biology is that a living cell arises from a living cell... so how did the first one happen? I recall one experiment where somebody basically created lots of lightning in a small ocean-like system and ended up creating amino acids, but that's still a far cry from life as we know it.
You're right! That is a far cry from life. For some reason, Miller and Urey did not commit billions of years of their free time to the experiment to more accurately portray how life really did begin. Those lazy buggers.
As for the first cell, I would guess that a simple self-replicating molecule, essentially a string of nucleotides like the ones produced in the Miller-Urey experiment, encountered naturally forming lipids. Those lipids tend to clump together and their water-fearing tails face inside, forming a barrier on the outside, which protects it. This would be considered a cell, one that is perhaps a million times simpler than modern cells.
Also, in debating this topic, EVOLUTION has no place here. I don't care how the first cell grew up and differentiated and became all the species; I want to know what led up to the first cell existing and replicating.
I didn't reply to this before, but I am afraid it has. Even in the RNA world scenario which is described in this thread, the 'agents' have three important properties. Firstly, whatever properties the agents have are coded in the agents themselves and passed on to their offspring. Secondly, reproduction rates can differ between 'species' of agents. And lastly: mutations occur to these organisms. Whenever you have these three properties, some form of evolution will occur.
I have wondered for a long time, how did life on earth start? The central dogma of biology is that a living cell arises from a living cell... so how did the first one happen? I recall one experiment where somebody basically created lots of lightning in a small ocean-like system and ended up creating amino acids, but that's still a far cry from life as we know it.
You're right! That is a far cry from life. For some reason, Miller and Urey did not commit billions of years of their free time to the experiment to more accurately portray how life really did begin. Those lazy buggers.
As for the first cell, I would guess that a simple self-replicating molecule, essentially a string of nucleotides like the ones produced in the Miller-Urey experiment, encountered naturally forming lipids. Those lipids tend to clump together and their water-fearing tails face inside, forming a barrier on the outside, which protects it. This would be considered a cell, one that is perhaps a million times simpler than modern cells.
I just wanted to correct you slightly: the cell membrane is a dual lipid layer, not a single one. Otherwise, the structure wouldn't be stable in a water-based environment.
Although there are some obvious benefits to protocells, as these things are called, it's still unclear how and why exactly they would arrive, as far as I know.
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I just wanted to correct you slightly: the cell membrane is a dual lipid layer, not a single one. Otherwise, the structure wouldn't be stable in a water-based environment.
Although there are some obvious benefits to protocells, as these things are called, it's still unclear how and why exactly they would arrive, as far as I know.
I was describing a micelle, which is single-layered.
I think that in order for necessary materials to cross a bilayer, special machinery (so to speak) is required. I went with a single layer membrane because I figured that would be strong enough to protect the genetic material inside, but porous enough to allow other materials through that it can use to replicate.
I'm no biologist or anything, but it seemed logical to me.
I just wanted to correct you slightly: the cell membrane is a dual lipid layer, not a single one. Otherwise, the structure wouldn't be stable in a water-based environment.
Although there are some obvious benefits to protocells, as these things are called, it's still unclear how and why exactly they would arrive, as far as I know.
I was describing a micelle, which is single-layered.
I think that in order for necessary materials to cross a bilayer, special machinery (so to speak) is required. I went with a single layer membrane because I figured that would be strong enough to protect the genetic material inside, but porous enough to allow other materials through that it can use to replicate.
I'm no biologist or anything, but it seemed logical to me.
Yeah, but micelles aren't water-filled. They're literally little blobs of fatty acids. All nucleotides are fairly hydrophilic, which means that they're unlikely to be found in the highly non-polar interior of micelles. Furthermore: RNA/DNA strings aren't as fragile as you think. They wouldn't really need protocells for direct protection.
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We have laboured long to build a heaven, only to find it populated with horrors.
Side question for all of you smart science people: I was curious, what were the conditions on the Earth during the time life is believed to have originated?
Side question for all of you smart science people: I was curious, what were the conditions on the Earth during the time life is believed to have originated?
Define life.
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We have laboured long to build a heaven, only to find it populated with horrors.
Side question for all of you smart science people: I was curious, what were the conditions on the Earth during the time life is believed to have originated?
Define life.
I'm not an expert in this area. But I can offer some thoughts. There's a few major conceptual points that are considered significant in the development of life.
1. Formation of basic organic molecules.
2. Advanced Biochemical interactions
3. RNA/ Viruses
4. Prokaryotic Life
5. Eukaryotic life.
6. Multicellular organisms.
Generally, everyone considers 4,5,6 "life". Generally everyone (scientists) considers 1,2,3 not to be life. For example, Viruses are not considered alive.
Nevertheless, they're important substeps in the development of life.
At any rate, Items 1,2,3 all occurred during the Precambrian Era. Life is first thought to have evolved 3.5 billion years ago. But in all honesty, we really know very little about what went on back then.
There's some biogenic material found that dates back to that era. We can also examine the geological strata to gain an idea of the atmosphere composition back then. But in reality, most of it has eroded or mixed away.
At any rate, during that period of time, we hypothesize several things. Keep in mind the precambrian spans a whopping 4 billion years.
1. There was little to no atmospheric oxygen during the precambrian era.
2. Continents formed during this time.
3. Water existed on the earth, but we don't know how much.
4. There was frequent volcanic activity
5. The earth was much hotter.
6. The crust of the earth formed during the early precambrian.
Side question for all of you smart science people: I was curious, what were the conditions on the Earth during the time life is believed to have originated?
Define life.
I'm not an expert in this area. But I can offer some thoughts. There's a few major conceptual points that are considered significant in the development of life.
1. Formation of basic organic molecules.
2. Advanced Biochemical interactions
3. RNA/ Viruses
4. Prokaryotic Life
5. Eukaryotic life.
6. Multicellular organisms.
Generally, everyone considers 4,5,6 "life". Generally everyone (scientists) considers 1,2,3 not to be life. For example, Viruses are not considered alive.
Nevertheless, they're important substeps in the development of life.
At any rate, Items 1,2,3 all occurred during the Precambrian Era. Life is first thought to have evolved 3.5 billion years ago. But in all honesty, we really know very little about what went on back then.
There's some biogenic material found that dates back to that era. We can also examine the geological strata to gain an idea of the atmosphere composition back then. But in reality, most of it has eroded or mixed away.
At any rate, during that period of time, we hypothesize several things. Keep in mind the precambrian spans a whopping 4 billion years.
1. There was little to no atmospheric oxygen during the precambrian era.
2. Continents formed during this time.
3. Water existed on the earth, but we don't know how much.
4. There was frequent volcanic activity
5. The earth was much hotter.
6. The crust of the earth formed during the early precambrian.
So, yeah. That was exactly the reason I asked him to expand on that point. ^^
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We have laboured long to build a heaven, only to find it populated with horrors.
To touch on how life even began in the first place, the explanation is simple once you understand it and doesn't require any supernatural intervention at all even with our limited knowledge base. While the exact process in which lifeforms develped would require physical or chemical evidence or some form, we can explain how this process would have ever begun without any real data whatsoever, just basic knowledge and logic. Richard Dawkins explains it well in The God Delusion (a very unoriginal source, but hey, it works)
"However small the number of planets with just the right conditions for life may be, we necessarily have to be one of the minority, because here we are thinking about it"
We can provide further weight to this by analysing what sort of chances life may have had of occurring
"If the odds of life originating spontaneously on a planet were a billion to one against, nevertheless that stupefyingly improbable event would still happen on a billion planets."
Thereby we can reasonably justify the creation of life simply by spontaneous chemical reactions forming basic DNA or DNA like chemicals, and from then evolution takes over. The sheer vastness of the universe eliminates the need for anything more than mere chance to explain life, unless the chances of life originating were something like a quadrillion to one against, the number of planets in the universe (a billion billion is reasonably conservative) is sufficient to assume that spontaneous chemical formation occurred.
To touch on how life even began in the first place, the explanation is simple once you understand it and doesn't require any supernatural intervention at all even with our limited knowledge base. While the exact process in which lifeforms develped would require physical or chemical evidence or some form, we can explain how this process would have ever begun without any real data whatsoever, just basic knowledge and logic. Richard Dawkins explains it well in The God Delusion (a very unoriginal source, but hey, it works)
"However small the number of planets with just the right conditions for life may be, we necessarily have to be one of the minority, because here we are thinking about it"
We can provide further weight to this by analysing what sort of chances life may have had of occurring
"If the odds of life originating spontaneously on a planet were a billion to one against, nevertheless that stupefyingly improbable event would still happen on a billion planets."
Thereby we can reasonably justify the creation of life simply by spontaneous chemical reactions forming basic DNA or DNA like chemicals, and from then evolution takes over. The sheer vastness of the universe eliminates the need for anything more than mere chance to explain life, unless the chances of life originating were something like a quadrillion to one against, the number of planets in the universe (a billion billion is reasonably conservative) is sufficient to assume that spontaneous chemical formation occurred.
This is called the "weak anthropic principle", and it answers some theist objections but not all. Dawkins' articulation is based on the premise that the odds of spontaneous generation are "a billion to one against", which sounds low, but the key thing to notice here is that those are still odds. If the theist contends that the spontaneous generation of life is impossible - a probability of zero flat - then the anthropic principle has nothing to say. So in order to jumpstart this argument, you first have to establish that spontaneous generation is possible.
And to be more specific, it must be possible with a fairly high probability. "A billion to one against" is not actually that small in the probabilistic sense. It's just 10-9. In contrast, the probability of, say, a monkey typing the text of Hamlet by randomly punching keys is 36-169 541, or about 10-263 857. This number is small beyond all comprehension. It begins with a string of zeroes half again as long as the Shakespeare play. Your body is smaller than the entire observable universe by a factor of "only" about 10-82. It's just never going to happen, not if a billion billion monkeys on a billion billion planets spend a billion billion years typing a billion billion plays per year. So if the proposed spontaneous generation of life is, like a monkey at a typewriter, merely a matter of waiting for the right randomly-selected tokens to line up in the right sequence, then all the vastness of the universe won't even make a dent in the improbability. To explain the origin of life, we need to propose a mechanism that brings a little more order to the chaos.
And don't get me wrong, biologists have put lots of such mechanisms on the table. But they actually had to put in some work doing it. Just waving one's hands and saying "Probability can explain life!" does not cut it.
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Yes, obviously there is more to it. We have to actually determine the chance of life originating. But there is a very large margin, current estimates are more like 10^24 meaning we'd need a good septillion to one against at least to produce any reasonable doubt. The point is that it is very possible that chances we're sufficient to allow life, that God is currently, and for all foreseeable future, unnecessary. For the purposes of atheism vs theism we don't need to go in any more detail. More important than scientific theory is scientific principle, showing how our theories can explain things acts to demonstrate the validity of a scientific basis for worldview. If you want to prove the superiority of atheism, it's more insurmountable to look at how devoid theism is of evidence and explanation, it's a baseless idea inserting grandiose claims for actual reason (chiefly, the figure of god itself is given no real explanation of it's origins or form, and this figure is the foundation of the whole belief). Proving scientific theory wrong doesn't prove theism right. Even if evolution, atomic theory and gravity were proved wrong, science would still stand and still disagree with theistic ideas for the very same reason that it always did, there would just need to be a new explanation found for such things, religion certainly wouldn't suffice.
1. Formation of basic organic molecules.
2. Advanced Biochemical interactions
3. RNA/ Viruses
4. Prokaryotic Life
5. Eukaryotic life.
6. Multicellular organisms.
Hrm... Well you said 1-3 occurred during the Precambrian, so I guess the transition from 3 to 4, as 4 is when we start getting into things that are actually alive.
@highroller
4,5,6 on that list all happened Precambrian as well. The Cambrian saw the development of more complex life with eyes and backbones and such.
I found this website (http://www.infoplease.com/cig/biology/origin-prokaryotes.html) while browsing that has a decent summary of some of the earliest developments of life.
Also, in debating this topic, EVOLUTION has no place here. I don't care how the first cell grew up and differentiated and became all the species; I want to know what led up to the first cell existing and replicating.
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That's sort of like asking who shot me with this poison arrow. I don't see how tracing the origin of life to the beginning will change the fact we live in this world that we occupy.
candidus inperti; si nil, his utere mecum.
~~~~~
We can be pretty certain, though, that you're asking the wrong specific question. The first life would not have been a cell. Even a prokaryotic cell is a complex and adaptive structure that would have had to evolve over time. The leading suspects for "first life" are much simpler - either protein or RNA chains. Once you've got one of these self-replicating molecules, evolution is pretty much inevitable.
candidus inperti; si nil, his utere mecum.
Viruses, as we know them today, are obligate intracellular parasites, meaning they can't self-replicate. However, I wouldn't be terribly surprised (given our current speculation) if the first life-form was replicative RNA in a protein shell.
Abiogenesis, or biopoiesis, yeah. That's what Blinking Spirit linked. I've never heard of tardigrades before... that's really cool!
Thank you all for your comments so far. It's only been 4 hours but I know a lot more now than I did 5 hours ago.
Standard: UGB Hardened Skulker
Commander:
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WUBRG Progenitus / Allies
UBR Scry / Mill
WUB Dakkon Landfall
The mains issues with this theory at the moment is that there is a mathematical limit to the amount of information a mutating, self-replicating string can hold. Hogeweg, among others, has been doing some interesting research in how these early 'organisms' could overcome this information threshold, but it's still very theoretical.
There are some other fun theories, however. One of those was offered by Arthur C Clarke, who noted that life may have a cosmic instead of an earthly orbit. Scientists had noted that all of our satellites were covered in a thin layer of fecal matter, due to the sanitation practices of astronauts. He posited that if other races had the same issues, life may have been brought to earth that way.
Eh, yeah, it is an issue. However, we don't need to know the precise pathway. We'd like to know the general strokes of how life originated on this planet.
That simile is about as relevant here as a clown-cart.
Not directly related to abiogenesis, but cool nonetheless, is the hypothesis that life did fall to Earth... after being ejected from Earth. The story goes that at some points during Earth's early history, in particular during the Late Heavy Bombardment, conditions were so bad that life had a better chance surviving in the vacuum of space than down here. So the debris thrown into orbit by the impacts functioned like arks for our earliest macromolecular forebears, falling back down to restart the process once things had cooled down a bit.
Also, the Buddha was just plain wrong there. My fundamental critique of Buddhism is that he didn't question the assumption that reincarnation occurs, upon which the whole philosophical edifice is premised.
candidus inperti; si nil, his utere mecum.
Eh, true, but it's a completely viable answer to the question "where does life on earth come from".
That's a pretty cool hypothesis. I never heard it before, but it explains the almost over-designed nature of bacterial spores.
A DNA string is not so different from a binary string from an information point of view: the longer it is, the more information it can contain. The issue is that at some mutation rate, even the best sequence is no longer able to replicate itself with enough precision to sustain itself. This mutation rate is called the information threshold (or error threshold). Shuster and Eigen did a lot of work on this.
You're right! That is a far cry from life. For some reason, Miller and Urey did not commit billions of years of their free time to the experiment to more accurately portray how life really did begin. Those lazy buggers.
As for the first cell, I would guess that a simple self-replicating molecule, essentially a string of nucleotides like the ones produced in the Miller-Urey experiment, encountered naturally forming lipids. Those lipids tend to clump together and their water-fearing tails face inside, forming a barrier on the outside, which protects it. This would be considered a cell, one that is perhaps a million times simpler than modern cells.
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My BUGWR Hermit druid BUGWR deck.
I didn't reply to this before, but I am afraid it has. Even in the RNA world scenario which is described in this thread, the 'agents' have three important properties. Firstly, whatever properties the agents have are coded in the agents themselves and passed on to their offspring. Secondly, reproduction rates can differ between 'species' of agents. And lastly: mutations occur to these organisms. Whenever you have these three properties, some form of evolution will occur.
I just wanted to correct you slightly: the cell membrane is a dual lipid layer, not a single one. Otherwise, the structure wouldn't be stable in a water-based environment.
Although there are some obvious benefits to protocells, as these things are called, it's still unclear how and why exactly they would arrive, as far as I know.
I think that in order for necessary materials to cross a bilayer, special machinery (so to speak) is required. I went with a single layer membrane because I figured that would be strong enough to protect the genetic material inside, but porous enough to allow other materials through that it can use to replicate.
I'm no biologist or anything, but it seemed logical to me.
My G Yisan, the Bard of Death G deck.
My BUGWR Hermit druid BUGWR deck.
Yeah, but micelles aren't water-filled. They're literally little blobs of fatty acids. All nucleotides are fairly hydrophilic, which means that they're unlikely to be found in the highly non-polar interior of micelles. Furthermore: RNA/DNA strings aren't as fragile as you think. They wouldn't really need protocells for direct protection.
Define life.
I'm not an expert in this area. But I can offer some thoughts. There's a few major conceptual points that are considered significant in the development of life.
1. Formation of basic organic molecules.
2. Advanced Biochemical interactions
3. RNA/ Viruses
4. Prokaryotic Life
5. Eukaryotic life.
6. Multicellular organisms.
Generally, everyone considers 4,5,6 "life". Generally everyone (scientists) considers 1,2,3 not to be life. For example, Viruses are not considered alive.
Nevertheless, they're important substeps in the development of life.
At any rate, Items 1,2,3 all occurred during the Precambrian Era. Life is first thought to have evolved 3.5 billion years ago. But in all honesty, we really know very little about what went on back then.
There's some biogenic material found that dates back to that era. We can also examine the geological strata to gain an idea of the atmosphere composition back then. But in reality, most of it has eroded or mixed away.
At any rate, during that period of time, we hypothesize several things. Keep in mind the precambrian spans a whopping 4 billion years.
1. There was little to no atmospheric oxygen during the precambrian era.
2. Continents formed during this time.
3. Water existed on the earth, but we don't know how much.
4. There was frequent volcanic activity
5. The earth was much hotter.
6. The crust of the earth formed during the early precambrian.
So, yeah. That was exactly the reason I asked him to expand on that point. ^^
"However small the number of planets with just the right conditions for life may be, we necessarily have to be one of the minority, because here we are thinking about it"
We can provide further weight to this by analysing what sort of chances life may have had of occurring
"If the odds of life originating spontaneously on a planet were a billion to one against, nevertheless that stupefyingly improbable event would still happen on a billion planets."
Thereby we can reasonably justify the creation of life simply by spontaneous chemical reactions forming basic DNA or DNA like chemicals, and from then evolution takes over. The sheer vastness of the universe eliminates the need for anything more than mere chance to explain life, unless the chances of life originating were something like a quadrillion to one against, the number of planets in the universe (a billion billion is reasonably conservative) is sufficient to assume that spontaneous chemical formation occurred.
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This is called the "weak anthropic principle", and it answers some theist objections but not all. Dawkins' articulation is based on the premise that the odds of spontaneous generation are "a billion to one against", which sounds low, but the key thing to notice here is that those are still odds. If the theist contends that the spontaneous generation of life is impossible - a probability of zero flat - then the anthropic principle has nothing to say. So in order to jumpstart this argument, you first have to establish that spontaneous generation is possible.
And to be more specific, it must be possible with a fairly high probability. "A billion to one against" is not actually that small in the probabilistic sense. It's just 10-9. In contrast, the probability of, say, a monkey typing the text of Hamlet by randomly punching keys is 36-169 541, or about 10-263 857. This number is small beyond all comprehension. It begins with a string of zeroes half again as long as the Shakespeare play. Your body is smaller than the entire observable universe by a factor of "only" about 10-82. It's just never going to happen, not if a billion billion monkeys on a billion billion planets spend a billion billion years typing a billion billion plays per year. So if the proposed spontaneous generation of life is, like a monkey at a typewriter, merely a matter of waiting for the right randomly-selected tokens to line up in the right sequence, then all the vastness of the universe won't even make a dent in the improbability. To explain the origin of life, we need to propose a mechanism that brings a little more order to the chaos.
And don't get me wrong, biologists have put lots of such mechanisms on the table. But they actually had to put in some work doing it. Just waving one's hands and saying "Probability can explain life!" does not cut it.
candidus inperti; si nil, his utere mecum.
RUNIN: Norse mythology set (awaiting further playtesting)
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I'm here to tell you that all your set mechanics are bad
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4,5,6 on that list all happened Precambrian as well. The Cambrian saw the development of more complex life with eyes and backbones and such.
I found this website (http://www.infoplease.com/cig/biology/origin-prokaryotes.html) while browsing that has a decent summary of some of the earliest developments of life.
RUNIN: Norse mythology set (awaiting further playtesting)
FATE of ALARA: Multicolour factions (currently on hiatus)
Contibutor to the Pyrulea community set
I'm here to tell you that all your set mechanics are bad
#Defundthepolice