Saturday, February 04, 2012

Where did that prebiotic life go... I know I left it here somewhere

Charles Darwin addressed the question, suggesting that the original spark of life may have begun in a "warm little pond, with all sorts of ammonia and phosphoric salts, lights, heat, electricity, etc. present, so that a protein compound was chemically formed ready to undergo still more complex changes". He went on to explain that "at the present day such matter would be instantly devoured or absorbed, which would not have been the case before living creatures were formed."
thus the idea that prebiotic chemistry would just be absorbed into biotic chemistry when evolution had reached that level, was born. I must admit that it appears self evident. However, I can imagine progressions of events that would indicate completely the opposite- ie, that in the environment that life evolved/developed, not only would biota not destroy per-biota, but would rely on its function to such an extent that it could not. Just as we could not survive if we destroyed every bit of bacteria on our body.
Oparin proposed that the "spontaneous generation of life" that had been attacked by Louis Pasteur did in fact occur once, but was now impossible because the conditions found on the early Earth had changed, and preexisting organisms would immediately consume any spontaneously generated organism.
Again, the assumption comes in that spontaneously generated organisms could not survive alongside existing organisms. The point is, since we cannot know whether this is the case or not, because we don't have the slightest idea where or when it happened, nor the exact chemical composition when it happened, we could certainly not prove it, nor even give it a probability. Perhaps parsimony which dictates that we assume life started on Earth would follow with the conclusion that, since there is not even a scrap of evidence for prebiotic evolution here, that biota had an evidence destroying capacity in that regards, much as some species can disappear without a trace. However, if one accepts biogenesis happening elsewhere, we would have to assume that we could find evidence for it at that location, even if there is also biota at that location.

12 comments:

Chris Fellows said...

Obviously life does not need proto-life to survive ("not only would biota not destroy per-biota, but would rely on its function to such an extent that it could not") because we exist without proto-life. The justifications for life replacing proto-life are: (1) That all complex organic chemicals can be utilised in some way by existing life, and proto-life ancestral to us must necessarily be composed of complex organic chemicals, so they are food (2) by analogy from design- and teleology is permitted in the world of natural selection- one form is replaced by another because the new form is *better*. It is like the Gary Larson cartoon: "With the amazing new "knife", you only need to wear the *skins* of those dead animals." It is not a matter of Inuit wearing fur instead of artificial fibre, but the preposterous hypothetical of them wearing dead animals instead of artificial fibre. There are no extreme environments where proto-life could hang on but life cannot, because life is *better*.

Compared to what I mean by proto-life, you and I and bacteria are as alike as a large number of identical raindrops, so it is rhetorical sleight-of-hand to talk about relations between us and bacteria as if we are a superior form of life.

Of course, I admit that my preconceptions are somewhat clouded by my terrestrial experience of a very dense crowded biosphere, and it is entirely reasonable that lumps of matter could have been ejected from molecular gas clouds and retain protolife, since space is big and empty and they might never happen to run into lumps of matter containing life. So that is where that prebiotic life is. However I will continue to argue vociferously that where life is, pre-life is not.

BTW, have you read Fred Hoyle's The Black Cloud? (It is apparently Richard Dawkins' favourite, a fact which led him to grow several inches in my estimation...)

Marco said...

I still think this just amounts to an assumption based on parsimony rather than being based on any evidence. There are no examples on Earth, and since life started on a planet like Earth, pre-biota must have been extincted by osmosis. In fact I might even agree if I thought life *must* have begun on a planet like Earth. At the moment I am just thinking Earth is just a whoppng huge comet with a permanent coma and little Ice.

Incidentally, my view is that the organisms that relied on pre-biota would have been extincted by the great oxygen catastrophe, and thus extincted all pre biota at the same time, with the recognition that all the primordial soup successful experiments require a highly reducing atmosphere - The current Earth environment, even in the depths of the crust, are not a good environment for pre-biota.

I believe the enviroments deep inside comets would be just fine for pre-biota coexisting with anaerobic bacteria.

If Evolution on earth is a bush, not a ladder, why would the "roots", pre-biota, be a climb up to "something better"

Chris Fellows said...

The great oxygen catastrophe is like the analogue network shutting down. Utterly irrelevant to the replacement of telegraphs by landlines. Think further back and further away.

If Evolution on earth is a bush, not a ladder, why would the "roots", pre-biota, be a climb up to "something better"?

Sheesh. If all lebanese sweets are equally nummy, why wouldn't unground wheat kernels and honeycomb with live bees in it be nummy too, eh? If all ebooks are equally legible, why shouldn't text tatooed on slaves with cactus spines be equally easy to read? Didn't you read that book I sent you once upon a time? All about the fantastic optimised chemistry that every known living thing shares? Don't you think that is intrinsically *better* than some reaction you or I or Belousov and Zhabotinskii could whip up? Biochemical evolution has reached a serious local maximum, that is *why* the phenotypic evolution we see can be a bush and not a ladder.

I believe the enviroments deep inside comets would be just fine for pre-biota coexisting with anaerobic bacteria.

Why do you think you believe this? Don't you think if you really believed it, you wouldn't use the words 'I believe', but instead say something like: 'The environments deep inside comets would be just fine for pre-biota coexisting with anaerobic bacteria, because comets, like magical sugar pixies, have strange powers to bring harmony where once was conflict, etc. etc.''?

Marco said...

My father taught me one thing about books back in the day when I was reading the bible, the population bomb, and a book about space. Don't believe something you read as being authoritative without using your own logic as well. Quite frankly, the Earth is a crap place for chemical evolution to occur. Since we do not know whether biota were designed by the pinnacle of chemical evolution (much as we create computers/robots to do things we can't do), rather than being the pinnacle of chemical evolution of itself, and the only reason we choose the latter theory is because of parsimony, we shouldn't even bother to argue this point. If we do find something that looks like life 2.0 ( or life 1.0, with biota being life 2.0), we should be able to recognize it as such by looking for evidence of metabolism, reproduction, and perhaps even chirality. Comets do "split up", they do make the space around them more random, they do have chiral molecules. All we need is solid evidence that the interior has become more ordered (a telescope or other obvious internal structure that is hard to explain as being random) and we really have to make that call. If the outside of the comet turns out to be soot or a random looking jumble of racemic molecules, or we have proof that the interior of the comet is completely solid, so be it.

Marco said...

I finally got to looking at what "black cloud" was about. At first I was thinking non fiction :-). My main difference between my view (and in a different way your view) of panspermia from Hoyle/Wack.. theory is this idea of "preservation of information". My view is that information is, in its basic form, a dependence, or an if A then B, where B is has two possibilities, but the dependence favours one over the other. The only way that I can think of that random processes can lead to a "bit" of information such as this is if parity is violated. If parity is conserved, no new information can be generated. Information can be saved, through reproduction, but new dependencies cannot be generated without a further violation of parity. Although it sounds provable to me, I have a hard time even explaining the concept. Generation of information is not a trivial thing that just happens in the process of evolution. We need to reduce down to a physical chemical level and generate one bit of information as a proof of concept.

The view of mainstream scientists appear to be the same as yours - That there is no such thing as a conservation of information, and that it is nothing like the laws of conservation of energy/mass or other thermodynamic laws. You have said that sexual reproduction "generates" limitless information by shuffling genes while reproducing. I agree with Hoyle and creation scientists that it amounts to combining fixed amount of information in a multitude of ways while reproducing that information faithfully. No new information is generated.

Chris Fellows said...

I agree with Hoyle and creation scientists that it amounts to combining fixed amount of information in a multitude of ways while reproducing that information faithfully.

But it doesn't *necessarily* reproduce that information faithfully.

Wish we could drag someone else in on this conversation. Dialogue is good, but...

Marco said...

We've argued this point before, and having read Lennox, I am even more convinced that random mutations are 99.999999% non beneficial, and that information about what mutations may be beneficial is embedded in genetic information, such that no direct reliance on chance is necessary. On top of that, there are perfectly good naturalistic alternatives that are not even explored due to our silly belief in Ockham's razor magically giving us the correct answer.

Marco said...

I am sure I can get the Smalls involved, but only on FB, and their views on this are rather predictable and along Catholic vs New Atheist lines.

Chris Fellows said...

I would like to see a rigorous definition of information as you see it - as you say, something you are still groping towards getting into an explicable form. I can't really tussle with the concept until then. My feeling is that the concept of 'information' will prove to be an artifact of our language with no real biological meaning.

Marco said...

The irritating thing about this "conservation of information" hypothesis is that it is only the Intelligent Design mob (capital I) that seem even interested in it, and that only as an argument for their case in the false dichotomy between ID and evolution. My main plan in defining it is by reducing it down to one single bit of "meaning". For instance, when a cockroach is crawling along a tunnel and gets to an intersection, it chooses the darkest of the two choices, because it will be the safest one. That information of one choice between two is one bit of biological information of a decision which will always mean better survival. Without knowing what pre-life systems are, and how they survive better, this will be difficult, so we would have to accept a model for physical chemical life.

Marco said...

Just for the benefit of the argument, mind you

Marco said...

At some point the entity which is undergoing evolution would have to have free will. It should be able to make a decision to (say) go left or go right. Whichever way it goes, this needs to get recorded as the *right* way. The surviving entities will then lose their free will, and be programmed to go the way they initially went, given the same stimulus.