Origins of the First Living Cell and Evolution

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Origins of the First Living Cell and Evolution

Postby scientificphilosophe on March 30th, 2017, 9:39 am 

It came as a surprise to me that there is no credible theory of origin for the first living cell - or possibly the first 3 (one for each of the main forms of life).

The theory of evolution is strong once those cells have emerged, but not before. The only mechanisms for evolution are entirely dependent on a common process of reproduction within cells, and these also have to 'make mistakes'.. . yet the principle of strict cause & effect denies mistakes - there can only be inevitability.

There is no conceived mechanism for the process of evolution prior to the first cell, and from what I gather there is no evolutionary path for any of the 3 types of ribosome that are the functional core of the 3 types of cell.

There is talk that the origin of life may relate to crystals because they chemically reproduce themselves, but this has never been demonstrated in conjunction with amino acids. Indeed, science hasn't been able to demonstrate the creation of all amino acids necessary for life from a common set of circumstances and never in conditions that are believed to be plausible outside the lab.

This is a huge gap.

Is anyone aware of anything that may help to bridge the gap?
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Re: Origins of the First Living Cell and Evolution

Postby Forest_Dump on March 30th, 2017, 10:09 am 

scientificphilosophe wrote:It came as a surprise to me that there is no credible theory of origin for the first living cell - or possibly the first 3 (one for each of the main forms of life).

The theory of evolution is strong once those cells have emerged, but not before. The only mechanisms for evolution are entirely dependent on a common process of reproduction within cells, and these also have to 'make mistakes'.. . yet the principle of strict cause & effect denies mistakes - there can only be inevitability.

There is no conceived mechanism for the process of evolution prior to the first cell, and from what I gather there is no evolutionary path for any of the 3 types of ribosome that are the functional core of the 3 types of cell.

There is talk that the origin of life may relate to crystals because they chemically reproduce themselves, but this has never been demonstrated in conjunction with amino acids. Indeed, science hasn't been able to demonstrate the creation of all amino acids necessary for life from a common set of circumstances and never in conditions that are believed to be plausible outside the lab.

This is a huge gap.

Is anyone aware of anything that may help to bridge the gap?


Your problem is more one of temporal order. When we talk about the origins of the universe, were are talking about pretty much pure physics (and math and astronomy, etc.) because nothing biological (or argueably even "chemical") existed although we can and do project "ahead" since we know those areas came aout later.

Similarly, when we talk about the origins or the solar system and ultimately earth, we don't think much about biology because even liquid water didn't exist at first, because the surface of the earth was at first too hot for liquid water. But we do have to take into account that it came about later.

We do know that life did appear on earth but how that came about is within the realm of biochemistry and is known as abiogenesis (life from non-life if you will). This is certainly an active and interesting area of study. But evolutionary theory doesn't really apply as yet because evolutionary theory only applies to how we study life once life forms begin to reproduce and diversify. Presumably the first life forms probably didn't reproduce and some probably (certainly?) didn't reproduce with diversity. But, for the most part, we really don't care that much about them because they didn't survive long and didn't leave any real traces, at least that we have identified so far.
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Re: Origins of the First Living Cell and Evolution

Postby scientificphilosophe on March 30th, 2017, 10:47 am 

On the core point that you make - you say that a creature incapable of evolving must then evolve. How - if it doesn't have the capability?

My question does have a temporal issue in that science says that there isn't enough time since the start of our solar system (4.5 billion years ago) for the processes of life to have emerged by natural 'random' chemical reactions. The only way to bridge this gap is through a process - but there is no concept of what this process may have been - not even vaguely.

If the process of evolution cannot explain the origin of the first cell then you are back into the realms of God so it is an important consideration for everyone - whether you have religious leanings or not. It is not my problem per se.
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Re: Origins of the First Living Cell and Evolution

Postby Braininvat on March 30th, 2017, 11:10 am 

My question does have a temporal issue in that science says that there isn't enough time since the start of our solar system (4.5 billion years ago) for the processes of life to have emerged by natural 'random' chemical reactions.


Please read our forum guidelines and take note that a statement like this needs supporting citations. When did "'science say" that there was not sufficient time for a process of abiogenesis? This is an extraordinary claim and absolutely needs a citation.
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Re: Origins of the First Living Cell and Evolution

Postby Forest_Dump on March 30th, 2017, 11:31 am 

I think you have made several errors.

scientificphilosophe wrote:On the core point that you make - you say that a creature incapable of evolving must then evolve. How - if it doesn't have the capability?


First we are in the fortunate position of knowing that this did happen so the only real question is how did it happen. And there is tons of experimental data giving us answers here ranging from recreating those early conditions or the precursers of life to looking at what heppens then. There is and has been tons of stuff published since the 1970s but I have to admit that I am not a biochemist and not hugely interested in that specific topic (I am not sure that many people really are overly interested anymore unfortunately) because in many ways it is largely done and old news although I know technical afficianatos will dispute that strongly).

scientificphilosophe wrote:My question does have a temporal issue in that science says that there isn't enough time since the start of our solar system (4.5 billion years ago) for the processes of life to have emerged by natural 'random' chemical reactions. The only way to bridge this gap is through a process - but there is no concept of what this process may have been - not even vaguely.


Like I said, there is actually tons done here so "not even vaguely" is decidedly wrong. But of course we do know there was enough time because we know it did happen. In fact, if your time line is correct, given that the oldest fossils appear to be getting closer to 4 billion years old, it seems it happened relatively quickly - perhaps in less than half a billion years (or is that quick?) Again, it is not a question of whether it happened but working out the details of how it happened.

scientificphilosophe wrote:If the process of evolution cannot explain the origin of the first cell then you are back into the realms of God so it is an important consideration for everyone - whether you have religious leanings or not. It is not my problem per se.


Well no you are not for several reasons. Evolution applies to biological stuff - life. It doesn't apply pre-life for the same reasons that the rules of playing cards don't apply to times before anyone invented playing cards. Secondly you don't need to bring questions of God into this because can have and are being answered without recourse to that. Now if you want to thats fine but it definitely isn't necessary and not really helpful in any practical sense. I am. in fact, very much aware of how many people believe in the Midiwiwin Gotchee Manitou but don't see much mention of that in university chemistry or biology text books.
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Re: Origins of the First Living Cell and Evolution

Postby Forest_Dump on March 30th, 2017, 11:35 am 

By the way, if you are interested in this stuff, start here:

https://en.wikipedia.org/wiki/Abiogenesis

then try some university text books in chemistry, etc.
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Re: Origins of the First Living Cell and Evolution

Postby scientificphilosophe on March 30th, 2017, 12:19 pm 

All

I don't see how my comment :

"My question does have a temporal issue in that science says that there isn't enough time since the start of our solar system (4.5 billion years ago) for the processes of life to have emerged by natural 'random' chemical reactions. The only way to bridge this gap is through a process "

is at all contentious. All attempted explanations of the origin of the first cell are based on processes for this reason. If you are suggesting that purely random chemical reactions without a process happened to miraculously produce a living cell then you will find that very difficult to justify.

To say that there is lots of evidence to support a process is, I believe, totally incorrect because every theory I have seen has to skate over many gaps. That does not represent a viable theory. That is hope.

To take an example. Theories which suggest that DNA/RNA may have developed from undersea vents skate over the problem that the necessary amino acids can't seem to form in those circumstances. DNA is a template for assembling amino acids in a very precise sequence. How could this be developed without access to the amino acids on a regular basis?

Even if there was access to amino acids, I believe that the physical length of an average workable protein means that it has has more potential amino acid combinations than there are atoms in the Universe. Only one will be viable. Even if that one happened by chance, the likelihood of it being repeated is virtually nil.

There are millions of useless amino acid chains. Very few, (perhaps just a couple of hundred), could generate the most basic cell.... and you have to be able to produce all of the hundreds required at just the right moment that a membrane happens to encompass them... before any cell was able to produce them.

This is nowhere near a full description, even without entering the realm of the codes that DNA/RNA represent, how they 'knew' what was worth keeping or rejecting, and why unthinking chemicals would need them at all.

My question was whether there has been anything to help us bridge these gaps?
They are real gaps and we need explanations if if a non-God approach is to be justified other than on hope.
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Re: Origins of the First Living Cell and Evolution

Postby Forest_Dump on March 30th, 2017, 12:59 pm 

For myself, I think you are either arguing from ignorance or dishonesty. I will assume the former.

scientificphilosophe wrote:If you are suggesting that purely random chemical reactions without a process happened to miraculously produce a living cell then you will find that very difficult to justify.


To begin with, wouldn't you agree that it did happen? I will base this on two simle premises. 1) the oldest rocks on earth indicate quite clearly that the earth began as a molten ball too hot to support life. 2) Now there is life and, in fact, from looking at the fossil (and lots of other evidence) we see changes through time (which don't need to concern us here. So the simple point is figurng out how this change happened and the name of that kind of study is abiogenesis. If you are interested in it, read up on it.

scientificphilosophe wrote:To say that there is lots of evidence to support a process is, I believe, totally incorrect because every theory I have seen has to skate over many gaps. That does not represent a viable theory. That is hope.


First, yes, there is alot of evidence to support the idea of abiogenesis (see above). And such gaps that exist are the topic(s) of on-going research. You want to critique those guys, go ahead but make sure you have done your homework - criticizing something before you know what it is about ultimately makes you at least sound dishonest.

scientificphilosophe wrote:To take an example. Theories which suggest that DNA/RNA may have developed from undersea vents skate over the problem that the necessary amino acids can't seem to form in those circumstances.


See? Here is major problem #1. The available evidence clearly indicates that this happened before there was free oxygen in the atmosphere. And you really need to know what this means and is about before you can even hope to begin on this stuff. You are really trying to play chess with a bowling ball here.
scientificphilosophe wrote:Even if there was access to amino acids, I believe that the physical length of an average workable protein means that it has has more potential amino acid combinations than there are atoms in the Universe. Only one will be viable. Even if that one happened by chance, the likelihood of it being repeated is virtually nil.

There are millions of useless amino acid chains. Very few, (perhaps just a couple of hundred), could generate the most basic cell.... and you have to be able to produce all of the hundreds required at just the right moment that a membrane happens to encompass them... before any cell was able to produce them.

This is nowhere near a full description, even without entering the realm of the codes that DNA/RNA represent, how they 'knew' what was worth keeping or rejecting, and why unthinking chemicals would need them at all.

My question was whether there has been anything to help us bridge these gaps?


Okay, even if you read some pretty bad scientists, you will get a better idea of what you are talking about. I am not fond of people like Dennett and Dawkins, for a number of reasons that don't matter here, but they are actually pretty good writers and able to convey some basic ideas here pretty well. But stick to the topic - some f the other stuff they get into are not their strong suits.

scientificphilosophe wrote:They are real gaps and we need explanations if if a non-God approach is to be justified other than on hope.


Well, I prefer to keep God out of it because I don't like to wear ballet tutu's to professional wrestling matches and we all know that God demands that we do. Oh, wait, could I be arguing out of ignorance here? Maybe I better find out which God we are talking about before voicing an opinion here.
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Re: Origins of the First Living Cell and Evolution

Postby scientificphilosophe on March 30th, 2017, 1:26 pm 

To Forest Dump

I didn't think the rules of the forum allowed you to make personal insults. Please stop.

My motivation for the posts is that I am trying to defend the principles of Evolution against commentators advocating religious views. The points are largely valid and I don't have the answers. I hoped people on the forum would try to be helpful rather than malicious.

If you have evidence to suggest that amino acids can be produced in undersea vents then say so. I made an honest point because I was struggling for an honest answer. You haven't given one.

Yes we all know that life is here. There are quite a few theories which seem to acknowledge the unlikelihood of life purely developing here on Earth within the timescales and that is why they have suggested that life may have been seeded from a comet etc. The focus doesn't have to be entirely based here - but if it is, then a credible theory is needed.

Richard Dawkins is an advocate of Evolution based on the processes of the cell. I don't disagree. But that has nothing to do with the emergence of the first cell and in one TV series he ridiculed a scientist who was also a Christian - "How can you, a man of science, possibly believe in God?" The answer he got - "The Ribosome".
Dawkins went visibly white on screen and basically said - "Well there must be an explanation for that at some point" Faith on both sides.

I repeat my question - does anybody have any new ideas to throw into the mix?
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Re: Origins of the First Living Cell and Evolution

Postby Forest_Dump on March 30th, 2017, 1:54 pm 

Pardon me. I will give you some background on myself that might clarify some things. I did come from a Christian upbringing but became interested in the evolution vs. creationism debate back in the early to mid 1970s and have spent a lot of time thinking and studying this stuff. My expertise is on more recent archaeology but retain a strong interest in human evolution, evolutionary theory and its applications (including the problems of applying Darwinian theory to human cultural evolution), the (recent - being 19th to early 20th century) history of evolutionary thought and, to diminishing degrees, the evolutionary history of broader life. Because of my personal background as well as my interest in "logic", etc., as well as topics like ethics and religion broadly writ, I am also interested, at times in how and why this topic is of interest to some religious groups (particularly in the US) and how and why people do get wrapped up so much in it. And in my own experience, many of the more vocal types also are pretty dishonest about how they go about debating the topic (itself of some interest to me - sort of ends justify the means thing but pretty short sighted and even anachronistic). So my apologies because some of your material seemed like run of the mill disingenuous creationism stuff so I was trying to draw you out. Again my apologies. I will tackle some of your stuff in smaller bits.
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Re: Origins of the First Living Cell and Evolution

Postby Forest_Dump on March 30th, 2017, 2:09 pm 

scientificphilosophe wrote:If you have evidence to suggest that amino acids can be produced in undersea vents then say so. I made an honest point because I was struggling for an honest answer. You haven't given one.


The short answer is that while (modern) undersea vents might be like the environment in which these first appeared in many ways, asmino acids CANNOT be formed in these environments today because oxygen prevents that. In short, since photosynthetic life appeared (much later than the time we are talking about here), they have been releasing free oxygen into the water and atmosphere and oxygen oxydizes these chemical components. The oldest fossils we know of appear in rocks that indicate there was no free oxygen - in my general area, these are what are known as iron-banded silicates, dating t about 3+ billion years old (and, as an aside, I pay a bit more attention to them because prehistoric people, much much more recently, made stone tools out of them. And so do I.). Specifically iron chemically bonded with silica when the rock was formed in water. When oxygen appears in the atmosphere (and water), that chemical bonding stopped because iron "bond" much more readily with oxygen (as in rust).

Should there be some environments where amino acids could emerge, due to the lack of oxygen for some reason but all the other right ingredients, then most likely something would just come along and eat it up.

But biochemists have certainly managed to experimentally do some of this in a lab. Whats the key difference? Scientists have been working on this in maybe 100 labs, at the most, for less that 50 years in a total area equal to, what, one Olympic size pool? Compare that to a couple hundred million years with all the oceans of the world.
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Re: Origins of the First Living Cell and Evolution

Postby Forest_Dump on March 30th, 2017, 2:18 pm 

scientificphilosophe wrote:There are quite a few theories which seem to acknowledge the unlikelihood of life purely developing here on Earth within the timescales and that is why they have suggested that life may have been seeded from a comet etc. The focus doesn't have to be entirely based here - but if it is, then a credible theory is needed.


Sadly this is one of those bait and switch arguments. The idea of seeding from elsewhere just transplants the question of origins (i.e. abiogenesis) and evolution to somewhere else when in fact we don't really need to. As we have learned about the chemistry of the surface of the earth at more than 3 billion years ago, we have become aware that abiogenesis certainly could have happened here. In short we have learned tons since the 1970s. In the first few hundreds of millions of years when life appeared somewhere in all the oceans of the world, there were a lot of things going on. I actually think it is pretty remarkable that we have gotten so far in the literally less than 50 years since we really igured out what the DNA/RNA molecule really is.
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Re: Origins of the First Living Cell and Evolution

Postby Forest_Dump on March 30th, 2017, 2:23 pm 

scientificphilosophe wrote:Richard Dawkins is an advocate of Evolution based on the processes of the cell. I don't disagree. But that has nothing to do with the emergence of the first cell and in one TV series he ridiculed a scientist who was also a Christian - "How can you, a man of science, possibly believe in God?" The answer he got - "The Ribosome".
Dawkins went visibly white on screen and basically said - "Well there must be an explanation for that at some point" Faith on both sides.


I actually have a lot of problems with Dawkins (including but not limited to what I would call his religious bigotry) but on some things I think he is actually pretty good (gotta pay the devil his due, as it were). On this stuff I might recommend his "The Ancestor's Tale". I find I have problems with his grasp of processes that went on in the past in many ways but for this kind of thing (i.e., abiogenesis), Dawkins is actually pretty good. But before I would take him to task about what he thinks about ribosomes, etc., I would first find out what he says and what that means.
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Re: Origins of the First Living Cell and Evolution

Postby Forest_Dump on March 30th, 2017, 2:50 pm 

One last point (for now):

scientificphilosophe wrote:Even if there was access to amino acids, I believe that the physical length of an average workable protein means that it has has more potential amino acid combinations than there are atoms in the Universe. Only one will be viable. Even if that one happened by chance, the likelihood of it being repeated is virtually nil.


Calculating odds or stats is another common misdirection from these people. The odds of my winning the lottery are also pretty small to be practically "nil". Which is why, I guess, I haven't won a big one yet. So I suppose I should just give up. Except that 2 - 3 times a week someone does win one paying off $5 million or more. But then a lot of people are playing. As I said before, when you allow all the oceans in the world and a couple hundred million years PLUS the knowledge that something did happen (because we are here) then it is really only a question of how did it happen. Now you may well want to bring in god or aliens, etc.,, but frankly I find that is an unnecessary distraction that neither helps me figure out what happened over the last 3+ billion years nor does it do anything for my understanding of religion (which is a while different topic). Kind of like bringing a bowling ball to a chess game or wearing a pink tutu to a prefessional wrestling match. You could well think either is necessary to your enjoyment but I don't think it helps and might only work as a distraction.
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Re: Origins of the First Living Cell and Evolution

Postby Eclogite on March 31st, 2017, 9:44 am 

scientificphilosophe » Thu Mar 30, 2017 1:39 pm wrote:It came as a surprise to me that there is no credible theory of origin for the first living cell - or possibly the first 3 (one for each of the main forms of life).
I suspect you may be using theory here in the colloquial sense. Abiogenesis research is still at an early stage, too early for a theory or theories to have developed. What we do have are several credible hypotheses for the origin of life.

Most and probably all of the subsequent points you make in your OP are predicated on the truth of your statement: there is no credible theory of the origin of the first living cell. We need, therefore, to deal with that statement first. What is it that you find incredible out these hypotheses?

Stuart Kauffman's Autocatalytic Sets as described in, for example:

The Origins of Order . . . ISBN 0-19-507951-5
At Home in the Universe . . . ISBN 0-19-509599-5


Christian de Duve's pathway from thiosesters to RNA to protocells as described in:

Vital Dust . . . ISBN 0-465-09044-3

(This is one of several variants of the Iron-Sulphur theory which proposes energy from redox reactions of iron sulphides foster organic molecule synthesis.)


Cairn-Smith's Clay Templates as described in:

Genetic Takeover: And the Mineral Origins of Life . . . ISBN 9780521233125

There are several more hypotheses, many sharing elements between them, often with growing experimental work supporting their predictions. I am consequently perplexed as to what it is you find doubtful in these hypotheses.


I believe I can set your mind at rest as to the requirement that we find explanations for the three kinds of cell. I understand you to be referring to Woese's three domains: bacteria, archaea and eukaryota. These are thought to have evolved from a no longer extant predecessor. Do you see a problem with this?
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Re: Origins of the First Living Cell and Evolution

Postby scientificphilosophe on April 4th, 2017, 10:50 am 

All sides in the debate use stats - either they are valid or they are not. You said

Calculating odds or stats is another common misdirection from these people. The odds of my winning the lottery are also pretty small to be practically "nil". Which is why, I guess, I haven't won a big one yet. So I suppose I should just give up. Except that 2 - 3 times a week someone does win one paying off $5 million or more.


'Your number coming up' once is not the issue. Nobody believes that protein molecules last very long, so the process to develop all the necessary proteins and make them work together and all be present at the right moment seems to require the production of specific molecules on a regular basis, but the odds of a single recurrence without a mechanism would prevent this. The only mechanism we have is the living cell and its DNA templates... which didn't exist beforehand.
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Re: Origins of the First Living Cell and Evolution

Postby scientificphilosophe on April 4th, 2017, 11:09 am 

Hi Eclogite

Thanks for your comments & suggestions. I will certainly try to follow-through on many of them.

However from your understanding, do these hypotheses provide a regular way to generate valid proteins, DNA, & RNA - and allow for their interactions to develop into a coded production line?

As you probably realise, these are no small things and can't just be assumed.

Reference to an earlier life form from which all other Ribosomes evolved simply pushes the generation of the first cell to an earlier point - because the Ribosome is a key component of the living cell and therefore implies that same approach earlier.

As we have no evidence for any other form of life other than the cell it would seem strange to suggest that an entirely separate process to the cell, led to the first cell. Chemical environments might change but many would find it surprising that no other mechanisms evolved if there had been a different starting mechanism

It is also disheartening to see that there is absolutely no evidence for such an earlier primordial life form... or is there?
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Re: Origins of the First Living Cell and Evolution

Postby Forest_Dump on April 4th, 2017, 11:27 am 

Just a lottle bit to think about:

scientificphilosophe wrote:Nobody believes that protein molecules last very long,


Interesting point but why wouldn't they last long? Today, of course, they wouldn't because things like bacteria or fungi would probably eat them. But this was before such things existed. Or perhaps "during" since it has been proposed (can't remember where - sorry) that some life forms may have emerged, eaten all these things up and then starved before the whole process started up again a few(?) times before the first photosynthetic organisms appeared on the scene. The bigger problem would have been oxygen but then oxygen wasn't around either. Other chemical processes and UV etc radiation would probably have been at work but then all we need is more to survive than be decomposed. Again, with all the oceans of the world to play in and some hundreds of millions of years, I'd say the odds swing back. So why not have proteins simply hanging around in the water for a few millions of years, etc? And given the time and space available, how many trillions and trillions of molecules of all different kinds, unstable in todays atmosphere, might have built up before something kicked in? Probably didn't happen just once. Why not a million times before things became stablized?

scientificphilosophe wrote:As we have no evidence for any other form of life other than the cell it would seem strange to suggest that an entirely separate process to the cell, led to the first cell. Chemical environments might change but many would find it surprising that no other mechanisms evolved if there had been a different starting mechanism

It is also disheartening to see that there is absolutely no evidence for such an earlier primordial life form... or is there?


Well, viruses aren't cells (and there are debates about the extent to which we can call them "life"). And the latest is that mitochondria were an independent form of life that formed a symbiotic relationship with "cells".
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Re: Origins of the First Living Cell and Evolution

Postby scientificphilosophe on April 4th, 2017, 11:48 am 

Forest

You make an interesting point about viruses but to my knowledge they require production of specific proteins to form their shell, and only reproduce in living cells where the mechanisms for protein replication exist.

I thought that the main theory for their emergence was after the first cell.

Separately - your reply seemed to acknowledge that proteins would probably have a limited lifespan - so the question is how did they reliably replicate in sufficient numbers to allow a cell to form?
You cannot have 'chance' producing any more than one example of any specific protein due to the odds... which are valid odds. Neither can you realistically expect a single long lived protein to miraculously find all of the other 'single' necessary proteins, DNA and RNA across a pond let alone a planet.
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Re: Origins of the First Living Cell and Evolution

Postby Forest_Dump on April 4th, 2017, 12:08 pm 

scientificphilosophe wrote:You make an interesting point about viruses but to my knowledge they require production of specific proteins to form their shell, and only reproduce in living cells where the mechanisms for protein replication exist.


My only point here was in rebutal to one of yours:

scientificphilosophe wrote:As we have no evidence for any other form of life other than the cell


As to:

scientificphilosophe wrote:I thought that the main theory for their emergence was after the first cell.


I thought they were older but this is a bit beyond me.

scientificphilosophe wrote:Separately - your reply seemed to acknowledge that proteins would probably have a limited lifespan - so the question is how did they reliably replicate in sufficient numbers to allow a cell to form?
You cannot have 'chance' producing any more than one example of any specific protein due to the odds... which are valid odds. Neither can you realistically expect a single long lived protein to miraculously find all of the other 'single' necessary proteins, DNA and RNA across a pond let alone a planet.


I think the key here seems to be about playing the odds and this is an area where a lot of people get a bit flumuxed. To me the bottom line is that if the odds are anywhere above absolute zero then eventually they will pay off and more than once so long as there is enough time to play often enough. The chances of becoming the richest person in the world are less than one in six billion. But someone always is. Reconstructions of the earth during the earliest years indicates it was very unstable with lots of electrical storms, uv and ground radiation, high heat with lots of volcanic activity spewing out tons of chemicals, meteorites crashing down, etc. Very hostile for modern life (especially without oxygen). But that also meant that lots could happen and the oceans could build up a chemical soup of the raw materials (lab experiments do indicate that they can build up quickly). So given all this and hundreds of millions of years why couldn't it happen hundreds, thousands or even millions of times, purely by chance even if the odds are extremely long?
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Re: Origins of the First Living Cell and Evolution

Postby BioWizard on April 6th, 2017, 12:44 pm 

scientificphilosophe » 04 Apr 2017 09:50 am wrote:'Your number coming up' once is not the issue. Nobody believes that protein molecules last very long, so the process to develop all the necessary proteins and make them work together and all be present at the right moment seems to require the production of specific molecules on a regular basis, but the odds of a single recurrence without a mechanism would prevent this. The only mechanism we have is the living cell and its DNA templates... which didn't exist beforehand.


Why do you assume that large polypeptides had to exist and come together all at once as a prerequisite for a living system to emerge? Sounds like a combination of false premise and false dichotomy.

By the way, how do you define a living system in this context?
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Re: Origins of the First Living Cell and Evolution

Postby scientificphilosophe on April 10th, 2017, 11:04 am 

BioWizard

Why do you assume that large polypeptides had to exist and come together all at once as a prerequisite for a living system to emerge? Sounds like a combination of false premise and false dichotomy.

By the way, how do you define a living system in this context?



The point is that we are trying to explore the potential for developing the first living cell. These do contain a significant number of proteins plus a series of linked processes based on codes that form the only basis of reproduction that seems to exist.

It's not unreasonable to speculate that they have to originate somewhere... except that 'random activity' means that while one of those viable proteins might emerge once it is unlikely to arise twice and it it not credible to believe it will happen 3 times in the lifetime of our planet without a specific mechanism that can reproduce those proteins reliably.

To then extend the same odds to a number of necessary proteins is completely unrealistic.

The only known chain of mechanisms to achieve protein replication (including human manipulation in the lab) involves the ribosome... which is also made partly of proteins.
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Re: Origins of the First Living Cell and Evolution

Postby scientificphilosophe on April 10th, 2017, 11:15 am 

Forest

But that also meant that lots could happen and the oceans could build up a chemical soup of the raw materials (lab experiments do indicate that they can build up quickly). So given all this and hundreds of millions of years why couldn't it happen hundreds, thousands or even millions of times, purely by chance even if the odds are extremely long?


To my knowledge lab experiments have never been able to generate all of the 22 amino acids necessary for life even in the most extreme chemical make-ups. It is also acknowledges that the most successful soups involve percentages of hydrogen that are not thought credible. (Check on Wikipedia as as initial check on this if you like).

You have assumed several times that there was no oxygen in those early environments when water and oxygen are everywhere on the planet. Did they suddenly materialise out of nowhere? No. They are highly likely to have been available in the earliest days of the planet.

Even with hundreds of millions of years the odds of viable proteins arising are very rare. For them all to happen in the same place at the same time is not currently credible without a mechanism... which isn't currently known.
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Re: Origins of the First Living Cell and Evolution

Postby vivian maxine on April 10th, 2017, 11:46 am 

Scientificphilosophe, I wanted so much to find this thread yesterday but I had a very full day and didn't get it. An item that I posted yesterday seems to relate to your OP question. In Biochemistry, "Mineral surfaces as possible source of earliest life." I hope this link gets to it: viewtopic.php?f=18&t=32719

In addition, another article I have been trying to find since you started this thread seems relevant. I did search for it at Science Daily but had no luck. Science Daily had an article several weeks ago in which there was suggestion that the minerals at (or close to?) the Big Bang might have already had the makings of life.

Is any of this helpful?

Forest, it may have been impossible for life form to have been present at the exceedingly hot Big Bang. However, in view of the above posts, would you grant that the earliest necessities to form life may have been present? Stress "may have been".
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Re: Origins of the First Living Cell and Evolution

Postby scientificphilosophe on April 10th, 2017, 1:17 pm 

Hi Vivian

Thanks again for pointing out this article.

For the purposes of this thread it reinforces the need for a mechanism of reproduction prior to the living cell.
In the past, whether people have considered the banks of muddy pools; the surfaces of crystals; undersea vents etc. the same problem arises - as implied in this article...
the environments suitable for amino acids are not normally conducive to RNA/DNA etc.

The research you pointed out clearly shows that the scientists involved understand the difficulties and are experimenting with ways to overcome it... although they haven't yet demonstrated that their outline ideas have been viable.
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Re: Origins of the First Living Cell and Evolution

Postby Forest_Dump on April 10th, 2017, 2:15 pm 

scientificphilosophe wrote:You have assumed several times that there was no oxygen in those early environments when water and oxygen are everywhere on the planet. Did they suddenly materialise out of nowhere? No. They are highly likely to have been available in the earliest days of the planet.


I will again try to be brief (because I am wrapped up in other things).

Oxygen as atoms was of course present but it was chemically bound up. Specifically largely in carbon dioxide (CO2). When photosynthesis started, then CO2 is taken out of the atmosphere and the carbon is chemically bonded with other things (mostly nitrogen and hydrogen) to make complex organic molecules that use relatively fewer oxygen molecules. So you end up with a lot of left over pxygen atoms that are released into the water and ultimately air, as free oxygen (O2). Once there is a lot of free oxygen floating around, oxygen is available to chemically bond with other things (like iron) or be breathed by oxygen breathers (like us) to use in the digestion of sugars, carbohydrates, etc., that expells CO2 again.

As I mentioned before, we know there was no free O2 around back then because we have rocks (i.e. iron banded silicates near where I live in the Gunflint formation) that could not have formed if there was free O2 in the atmosphere and this rock has microscopic (but sometimes just visible) fossils in it dating more than 3 billion years old.

Let me give you another one of those little mind puzzles on stats. I recently read that more than 99% of all creatures that have ever lived died without having surviving offspring. In other words, the chances of any creature being born having offspring in turn successfully have offspring are almost 100 to 1 against. However, since I am alove now, obviously my ancestors beat the odds in an unbroken streak for hundreds of millions of generations (estimated) since life began (taken from Dawkins "Ancestor's Tale"). But, since I do not have children that lived (actually technically not 100% true but easy to imagine), that unbroken streak is now coming to an abrupt end and my specific genetic line is now going to be extinct forever (although my brother has kids). Billions of years and hundreds of millions of generations of evolution to produce the unique genetic blend that is me, gone forever. What are the odds?
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Re: Origins of the First Living Cell and Evolution

Postby vivian maxine on April 10th, 2017, 3:32 pm 

Forest is right. Oxygen (safe oxygen) was a late-comer. Let me give you this from Nigel Calder's "Timescale" - one of the best books I ever read. He calls it "an atlas of the fourth dimension". I call it a time-lined history of the universe from Day One to now. A book worth having on your shelf. It is a bit old (first published 1983) but I doubt it is much out of date. Maybe use some new facts. Quote:

"Oxygen Revolution, 1800Myr. Although animals need oxygen to survive, primitive life began in the absence of free oxygen, and when oxygen built up in the sea-water, it was deadly poison for organisms unequipped to deal with it."

He goes on to explain that oxygen originated as a by-product of plants. Then: "The definitive world-wide change that signaled the appearance of free oxygen was the appearance of red beds, characterized by an abundant red oxides of iron in sedimentary rocks."

He indicates that his information came from B F Windley in "The Evolving Continents". I do not know that book.
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Re: Origins of the First Living Cell and Evolution

Postby scientificphilosophe on April 11th, 2017, 1:06 am 

Forest - this seems a fundamentally flawed argument

However, since I am alove now, obviously my ancestors beat the odds in an unbroken streak for hundreds of millions of generations (estimated) since life began (taken from Dawkins "Ancestor's Tale").


Your ancestors haven't beaten any odds because they were part of a certain process - one that began after the first cell.

Our problem is what happened before the first cell.

On your other point...

As I mentioned before, we know there was no free O2 around back then because we have rocks (i.e. iron banded silicates near where I live in the Gunflint formation) that could not have formed if there was free O2 in the atmosphere and this rock has microscopic (but sometimes just visible) fossils in it dating more than 3 billion years old.


You and others seem to presume certain conditions and then extrapolate them to everything on the planet.

While some rocks originated in an oxygen free environment, I understand that other rocks could form with some free oxygen present.

Equally we know it is conceivable for conditions in the core of a new planet to have concentrated the heavier elements and expelled the lighter elements as a gas in the outer layers. The rocks could effectively form in the core and not be exposed to free oxygen, while it is still present in the planet as a whole.

I will continue this response with Vivian.
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Re: Origins of the First Living Cell and Evolution

Postby Forest_Dump on April 11th, 2017, 8:35 am 

Okay, well, I will simply summarize. In the OP you asked if there were any credible theories (technically hypotheses but a trivial point) for abiogenesis. I think it is safe to say you have been exposed to a few but I suspect that is just the tip of the iceberg and that there is a lot more, some better some worse, but probably requiring a lot more technical competence in ghemistry, etc., than most of us here can provide.

Repeatedly you did note a discomfort with the statistics, believing the odds appear to be too long for the results to have come about. Frankly I think here your problems are with the logic. I might suggest looking up a text book by Ian Hacking in probability and logic but that might be asking too much. To me the key points are that we know life is here on this planet and that research in physics, chemistry, biology and geology is providing fruitful avenues for further research and exploration. We don't have all the answers yet, I suppose, but then there are a lot of questions for which we don't have all the answers.

Early on you did mention religious concerns:

scientificphilosophe wrote:If the process of evolution cannot explain the origin of the first cell then you are back into the realms of God so it is an important consideration for everyone - whether you have religious leanings or not. It is not my problem per se.


Where I live now, the Middle Eastern religions (Judaism, Christianity and Muslim) have not been very successful in making inroads but most do believe in a Creator but do not find science to be a challenge to their faith in the same way that some others do. Here the clash may be more between western medicine and tradional healing but it is not as strong a clash in values. Institutional hospitals and university-trained doctors commonly work together with traditional healers and the local hospital even has a room where tobacco is burned in religious ceremonies. So I am not longer as immersed in the logic and reasons for why some religious people, and perhaps scientists as well, find such a challenge with alternate beliefs. Sure, personally, I see some problems with burning tobacco to treat someone who has some lung disease such as TB or cancer just as I see some issue with trying to reconcile ID with science but in both cases it is clear we are mixing religion and politics with science and that can be an uncomfortable mix and something to think about. However, for the "pure science", as far as I can see, religious beliefs have not and do not bring much to the table to answer questions such as abiogenesis, the actions of bacteria, viruses fungi, etc. Believe what you want I guess but personally I don't think we can or should expect science to validate our beliefs in a Gitchee Manitou. Probably better to go the old-fashioned route - by faith and faith alone.
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Re: Origins of the First Living Cell and Evolution

Postby Braininvat on April 11th, 2017, 10:01 am 

If God can sit in a laboratory and stitch together proteins and protein-synthesizing nanomachines and then plant them in ponds on the young Earth, then you have definitely postulated a metaphysical theory that God is, itself, a physical being that interacts with other physical matter. And using such a postulate to fill explanatory gaps in the process of abiogenesis would seem outside the realm of biochemistry. So, either we get back to probabilistic analysis of spontaneous protein synthesis and replication, based on actual science, or we move the thread.
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