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How did DNA evolve?
Evolution assumes DNA exists, but as yet no account has been provided as to how

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How did DNA evolve?
jeeprs
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Posted 10/07/09 - 03:37 PM:
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#11
But I think everyone would have to agree that the issue of the evolution of DNA is far more speculative than the issue of the evolution of species. There is after all an abundance of fossil evidence to support the evolution of species. There is very little or no direct evidence to support the theory of the evolution of DNA. From what I recall - I am not a biologist - the very earliest fossil remnants are some impressions of soft-bodied sea creatures dating back billions of years, or maybe those strange structures that are found off the West Australian coast. But there is no direct evidence of the way life got to this point, and by this point, I think there were fully developed cells in existence.

As regards the burden of proof, I agree it would be difficult test for whether life evolved in accordance with some kind of form or template, however philosophically I find it much more attractive than the 'just so' approach. I still think that the underlying rationale of much evolutionary biology is that the assertion that 'God didn't do it' is regarded as an explanation of some kind.
Kwalish Kid
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Posted 10/07/09 - 04:40 PM:
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But no biologists is simply saying, "God didn't do it." They are using what we know of different kinds of bacteria and the behaviour of various chemicals to form a plausible history of early organisms.

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Arkady
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Posted 10/07/09 - 04:53 PM:
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jeeprs wrote:
...those strange structures that are found off the West Australian coast...


Stromatolites.

"Sit down before fact like a little child, and be prepared to give up every preconceived notion. Follow humbly wherever and to whatever abyss Nature leads, or you shall learn nothing."
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Wosret
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Posted 10/07/09 - 05:15 PM:
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I agree with K Kid about the evolution of DNA from RNA (Abiogenises having been demonstrated in a Manchester lab a couple months ago; in your face god-bothers!), so I won't say anything else on that. Instead I'll talk about "forms".

The OP is conflating genotypes and phenotypes when s/he talks about the specific forms that organisms take.

Forms are not determinable by genetics alone, as forms are malleable to large extents by environmental, and developmental factors. Something with the same genome can have a different form, depending on how its phenotypes presents themselves. You can't tell what an organism will look or behave like by examining its genetics alone -- there is no "lion form" built inside the genome of the lion. Every lion is different, and unique in its own way. Species are also in constant flux. Whether their forms are changing because of various selective processes, or during placid times by genetic drift, spontaneous mutation, happenstance, and likely a number of other reasons. In any case, species are in constant change, and thus even talking about approximate forms is a waste of time.

Edited by Wosret on 10/07/09 - 05:22 PM

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Wosret
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Posted 10/07/09 - 05:49 PM:
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Oh, oh! I heard Richard Dawkins say this recently when asked, and I thought it was just great. Someone asked him what the first human looked like, and he told them the exact same as the last ape!

"If you've got any last words, say 'em now." - Nadie.

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swstephe
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Posted 10/07/09 - 10:28 PM:
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Actually, DNA is pretty universally accepted to correlate to phenotype, (even hard-core creationists realize this). Therefore the phenotype of fossils is strong evidence for variations in DNA. DNA can be considered the media for transmission of phenotype to offspring. Looking at DNA between similar species is more confirmation. Of course, the other way of looking at the situation is that phenotypes are the media for transmission, (success or failure), of DNA evolution. So unsuccessful physical structures are eliminated from DNA more so than species evolution independently.

Ethics is the measuring of morality. Morality is the measuring of good. Good is the measuring of benefit. Benefit is the measure of values.
jeeprs
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Posted 10/08/09 - 01:30 AM:
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Actually, DNA is pretty universally accepted to correlate to phenotype


once it exists. The question is, how the DNA emerges from the 'sunlight pond' - how did DNA come about in the first place? How did it evolve? Did it evolve? How did all the pre-cursor chemicals 'adapt'? How can anything 'adapt' if it is not alive in the first place, and if it does not adapt, how does it evolve?

As regards form: I don't think 'form' implies a cookie-cutter type of morphology. I think it is much more subtle than that. The example of lions was given. Of course all lions are individuals, but not only are the recognisable as lions, they are also recognisable as felines. In fact if you wanted a better example of a Platonic form than a cat, you would be pretty hard-pressed to find it.

Incidentally, I am not a 'God-botherer' or a confirmed Christian (I will own up to being a cultural Christian). My problems with the neo-darwinist account of creation - I use that word intentionally - is that it is not philosophically coherent. There is no real account of the nature of cause. I will give an example. The current depiction of 'purpose' or 'intention' are such that these are really only understandable as characteristics of the human intelligence. Yet the human intelligence itself is purported to have evolved in the absence of any such thing as 'purpose' or 'intention'. Scientists such as Dawkins seem at great pains to argue that 'purpose' is an artefact of human consciousness, nothing else. But if that is the case, then the purpose actually has no purpose. It has only evolved by chance, presumably as an adaption, and not reflecting anything in reality, which is basically chaotic and dead. I don't think Dawkins or many of his ilk are actually mindful of the philosophical implications of this attitude. It basically puts the ego in the very centre of a meaningless existence and challenges it to make meaning where there is none. This was all of course perfectly well anticipated by the likes of Neitszche, Camus and Kafka. It is just that many of these glib modernists have not thought through the consequences of their outlook. Furthermore, if adaption is the sole driver of evolutionary development, then we have no reason to hope that our cognitive facilities will provides us with anything other than the wherewithal for survival. So how then did beings like Neitszche, Camus and Kafka, who could actually posit that there is no purpose, come to be? How fast could Mozart run away from a lion?smiling face

So I am actually favouring a position which is neither creationism nor neo-darwinism. I think life itself is an inherent property of the universe and will tend to develop wherever the circumstances favour it. In the same way that plants seek light, life seeks awareness, and in this sense evolution is perfectly purposeful. It is always attempting to give rise to the likes of us, and the likes of us were potentially present in the ratios and calibrations of energy and matter from the very instant of creation. It is much closer, I suppose, to a religious interpretation than a scientific one, but I honeslty feel science has over-reached in this question and is engaged in a great deal of speculation which has a strongly historically determined basis. In the philosophical tradition, the antecedents are mainly Pythagorism, Platonism and Plotinism, all of which have been heaved overboard by the very scientific tradition which they helped create, which is why the outcome is basically irrational.

That is my reading of it, anyway.
jeeprs
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Posted 10/08/09 - 02:14 AM:
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Actually a book which anticipates much of this idea, however with more science, and less philosophy, is At Home in the Universe by Stuart Kaufmann.
Kwalish Kid
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Posted 10/08/09 - 05:19 AM:
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swstephe wrote:
Actually, DNA is pretty universally accepted to correlate to phenotype

I can accept that this statement is true, as long as one also accepts that whether or not a phenoetype is expressed and how that phenotype is expressed is dependent upon other factors besides DNA.

"Scientific truth is always paradox, if judged by everyday experience, which catches only the delusive nature of things." - KM, V, P and P

Can you pass Religion 101?
Kwalish Kid
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Posted 10/08/09 - 05:31 AM:
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jeeprs wrote:
once it exists. The question is, how the DNA emerges from the 'sunlight pond' - how did DNA come about in the first place? How did it evolve? Did it evolve? How did all the pre-cursor chemicals 'adapt'? How can anything 'adapt' if it is not alive in the first place, and if it does not adapt, how does it evolve?

You can't have read the information from that page all that carefully if you still ask these questions using this language. The strognest contemporary hypotheses do claim is not that DNA arose initially with livinf organisms, they claim that the first living organisms used other mechanisms for heredity.

But a precursor chemical can adapt by thriving and reproducing more of itself in an environment even if it is not alive. Small changes to that chemical that allow it to reproduce more relative to the other chemicals in the area can be thought of as adaptations.
As regards form: I don't think 'form' implies a cookie-cutter type of morphology. I think it is much more subtle than that. The example of lions was given. Of course all lions are individuals, but not only are the recognisable as lions, they are also recognisable as felines. In fact if you wanted a better example of a Platonic form than a cat, you would be pretty hard-pressed to find it.

But one of the lessons of biology is that species are not ideal forms. Pick a set of definitions for a species that is not trivial and eventually a member of the population that one hoped to captrue with that definition will fall outside that definition.
Incidentally, I am not a 'God-botherer' or a confirmed Christian (I will own up to being a cultural Christian). My problems with the neo-darwinist account of creation - I use that word intentionally - is that it is not philosophically coherent. There is no real account of the nature of cause. I will give an example. The current depiction of 'purpose' or 'intention' are such that these are really only understandable as characteristics of the human intelligence. Yet the human intelligence itself is purported to have evolved in the absence of any such thing as 'purpose' or 'intention'. Scientists such as Dawkins seem at great pains to argue that 'purpose' is an artefact of human consciousness, nothing else. But if that is the case, then the purpose actually has no purpose.

Do not confuse your own philosophical incoherence with that of others. Simply because the creation of humans was not a goal does not mean that humans cannot have their own goals.
It has only evolved by chance, presumably as an adaption, and not reflecting anything in reality, which is basically chaotic and dead.

Evolution does not progress by chance. It progresses by selection based on the biuoligical and physical nature of environments.
I don't think Dawkins or many of his ilk are actually mindful of the philosophical implications of this attitude. It basically puts the ego in the very centre of a meaningless existence and challenges it to make meaning where there is none. This was all of course perfectly well anticipated by the likes of Neitszche, Camus and Kafka. It is just that many of these glib modernists have not thought through the consequences of their outlook. Furthermore, if adaption is the sole driver of evolutionary development, then we have no reason to hope that our cognitive facilities will provides us with anything other than the wherewithal for survival. So how then did beings like Neitszche, Camus and Kafka, who could actually posit that there is no purpose, come to be? How fast could Mozart run away from a lion?smiling face

Again, your facile understanding of biology is your undoing. Suvivial is not simply about being strong or fast. Nor must the survival survival benefit that we get from rational thought limit rational thought to be used for basic survival.
So I am actually favouring a position which is neither creationism nor neo-darwinism. I think life itself is an inherent property of the universe and will tend to develop wherever the circumstances favour it. In the same way that plants seek light, life seeks awareness, and in this sense evolution is perfectly purposeful. It is always attempting to give rise to the likes of us, and the likes of us were potentially present in the ratios and calibrations of energy and matter from the very instant of creation. It is much closer, I suppose, to a religious interpretation than a scientific one, but I honeslty feel science has over-reached in this question and is engaged in a great deal of speculation which has a strongly historically determined basis. In the philosophical tradition, the antecedents are mainly Pythagorism, Platonism and Plotinism, all of which have been heaved overboard by the very scientific tradition which they helped create, which is why the outcome is basically irrational.

That is my reading of it, anyway.

You are welcome to that reading. However, you will hopefully forgive us for demanding soe sort of evidence for that theory.

"Scientific truth is always paradox, if judged by everyday experience, which catches only the delusive nature of things." - KM, V, P and P

Can you pass Religion 101?
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