Level of Proof for Evolution

Discussion in 'Biology & Genetics' started by BenTheMan, Mar 23, 2007.

  1. synthesizer-patel Sweep the leg Johnny! Valued Senior Member

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    Tell you what Reiku - I'll throw you a bone in your elementary education in evolution

    Lesson 1 - what evolution actually is - lets start with a definition:

    (I just dug out my old biology dictionary)

    Here's the first line from the definition of the word evolution:

    "the development of new types of living organisms from pre-existing types........"

    The key word is "pre-existing" - shall I define that word for you too?

    Shall I post the rest of the definition for you?

    sheesh - hand-holding children on a sciforum - I ask you!
     
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  3. spidergoat Valued Senior Member

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    Please, stop this flawed argument. It doesn't hold up. DNA did not form at random, it evolved.


    So the calculation goes that the probability of forming a given 300 amino acid long protein (say an enzyme like carboxypeptidase) randomly is (1/20)300 or 1 chance in 2.04 x 10390, which is astoundingly, mind-beggaringly improbable. This is then cranked up by adding on the probabilities of generating 400 or so similar enzymes until a figure is reached that is so huge that merely contemplating it causes your brain to dribble out your ears. This gives the impression that the formation of even the smallest organism seems totally impossible. However, this is completely incorrect.

    Firstly, the formation of biological polymers from monomers is a function of the laws of chemistry and biochemistry, and these are decidedly not random.

    ...Secondly, the entire premise is incorrect to start off with, because in modern abiogenesis theories the first "living things" would be much simpler, not even a protobacteria, or a preprotobacteria (what Oparin called a protobiont [8] and Woese calls a progenote [4]), but one or more simple molecules probably not more than 30-40 subunits long. These simple molecules then slowly evolved into more cooperative self-replicating systems, then finally into simple organisms...

    ...The first "living things" could have been a single self replicating molecule, similar to the "self-replicating" peptide from the Ghadiri group [7, 17], or the self replicating hexanucleotide [10], or possibly an RNA polymerase that acts on itself

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    http://www.talkorigins.org/faqs/abioprob/abioprob.html
     
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  5. spidergoat Valued Senior Member

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    Evolution became such a compelling explanation, simply because it overcomes the problem of complexity forming that was neither designed nor random. That is the whole point of it.
     
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  7. synthesizer-patel Sweep the leg Johnny! Valued Senior Member

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    SG - Nice post - however I would take issue with a couple of things - first and foremost - with the lack of any fossil or experimental evidence in support of this at this time I think its going some to describe this as an abiogenic theory - hypothesis is probably a better term - I know it sounds picky, but we really must consider the level of audience that have been participating up until now - clear deliniations between a theory and a hypothesis are therefore important.

    Also using the term evolution also muddies the waters somewhat - particularly for those readers who don't really understand what evolution in its classic biological sense actually is - in this case we are talking more about chemical evolution - where ideas relating to selection etc have been borrowed and applied to abiotic processes, as there is a reasonable likelihood of some similar processes at work - however not nearly as close to the same level of certainty that we can apply to biological evolution.
     
  8. spidergoat Valued Senior Member

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    Ever heard of the Miller-Urey Experiment? There is supporting evidence for abiogenesis.
     
  9. Ophiolite Valued Senior Member

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    Nonsense, on at least two grounds.

    1.Miller-Urey postulated, and their experiment required, a strongly reducing atmosphere for the early Earth. Current evidence and the weight of considered opinion completely reject this.

    2. Secondly, all their experiments produced were a few amino acids and a couple of low molecular weight peptides. That is a million miles from being evidence for abiogenesis and far more restrictive in terms of chemical novelty than can be obtained from interstellar space.
     
  10. spidergoat Valued Senior Member

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    Abiogenesis, like evolution, does happen. We just haven't figured out how yet. There is a chance that it was panspermia, but that still means abiogenesis happened somewhere.
     
  11. Ophiolite Valued Senior Member

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    I'm not questioning abiogenesis at all. I'm simply pointing out that quoting Miller-Urey as evidence of abiogenesis is wrong.
     
  12. synthesizer-patel Sweep the leg Johnny! Valued Senior Member

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    Indeed - I gave it a positive mention a post or 2 back - the point I'm making is that we don't (yet) have enough evidence to have a viable theory of abiogenesis - we have lots of bits, but no string to tie it all together - so still very much in the realms of hypothesis - in terms of how it happened at least.

    I was just being a little picky about your terminology is all - you know - for the benefit of the idiot gallery

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  13. spidergoat Valued Senior Member

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    OK, it's not conclusive, but it is at least a plausable explanation. A naturalistic one which would have to be discounted before a theistic argument could be considered.
     
  14. synthesizer-patel Sweep the leg Johnny! Valued Senior Member

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    Just in case my view on Miller-Urey is misunderstood I'll reitterate


     
  15. CHARIZAARRRD!!! Registered Member

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    I hate statistics.... if it is so improbable that life could have formed from a singularity, maybe there were infinite singularities...............................

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  16. synthesizer-patel Sweep the leg Johnny! Valued Senior Member

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    Don't let it bother you C - life didn't form from a singularity - you're probably confusing abiogenesis with the big bang - neither of which have anything to do with the topic of discussion - evolution.
     
  17. CHARIZAARRRD!!! Registered Member

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    ... and it would be infinitely improbable that those statistics were correct!
     
  18. CHARIZAARRRD!!! Registered Member

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    lol, scientific terminology be my downfall

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    singularity as in "1. Same as singular point".. which is where the impossibility argument came from earlier in the thread.. surely there are infinite occurrences of a singular point in time?

    and life DID form from a singularity as in a Big Bang :|.. eventually

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    .. that's the argument being presented against evolution's explanation for our creation.. which I appreciate it does not set out to do.. rather the development of life

    also.. its hardly off topic....

    but i'm no scientist.. so i shall expect a slating shortly

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  19. synthesizer-patel Sweep the leg Johnny! Valued Senior Member

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    As has been pointed out many many many many times - evolution does not explain creation (AKA the origin of life) - this is because evolution does not seek to explain this - evolution explains how life arises from other forms of life that already exist.
    In other words evolution only begins AFTER life comes about in the first place.

    So it is impossible to argue against evolution's explanation for our creation - becuase it doesn't have one - indeed it CANT have one - because that isn't what evolution is about.

    make sense?
     
  20. CHARIZAARRRD!!! Registered Member

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    ..well I'm going to run before that happens!

    it's just I can't see how you can say life didn't come from a singularity :S.. when on both sides of the argument I felt there was agreement that it did.. and that one presented divine creation to explain this, whereas the other presented.. let me grasp for my scientific dictionary a sec.. ahh, abbey

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    without the creation of life, evolution is surely irrelevant
     
  21. synthesizer-patel Sweep the leg Johnny! Valued Senior Member

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    Well as long as we are clear on what the limits of the study of evolution and biology are.

    Perhaps I jumped the gun with you, and if I did I apologize.

    In my defence, I'm a little too used to fundaligionists bringing up cosmology when they think they are talking about biology (or vice versa) - (i.e going beyond the limits of that field of study like I just mentioned) - so when you mentioned a singularity I assumed you meant the big bang - my bad!

    Whether or not life began from a single point, we honestly and truthfully do not know - while what we would recognise as "modern" cellular life clearly does have a single lineage from prokaryotes to us, we could equally hypothesise that there were multiple starting points and precursors, and one dominant form of "protolife" parasitised or formed symbiotic relationships with other forms to produce something recognisable as a cell - in much the same way that primitive plankton use bacteria as endosymbiotes in place of organelles - we just don't know.

    We do however have a very good idea of what happened next - evolution - because we have tons of evidence for it - and none, read it: NONE, that contradicts it - so the origin of life - in terms of the study of evolution at least - really IS irrelevant - it happened, we don't know how, so lets figure out what happened next - that's biology in nutshell.
     
    Last edited: Aug 27, 2008
  22. CHARIZAARRRD!!! Registered Member

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    "that's the argument being presented against evolution's explanation for our creation.. which I appreciate it does not set out to do.. rather the development of life" << me, lol

    yes, i agree with that.. evolution was being used as a ‘straw man’ explanation for the creation of life, and i was challenging the notion of impossible complexity that was used to discredit this distorted (and thus weakened) view of evolution .. poorly, perhaps, but that does not mean I should limit my participation.. for if I knew all the answers, there would be no need for discussion in the first place (I realise I might be really out my depth, but still!)
    love the use of bold italics by the way

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    .. i've just seen your most recent post, and no it was my bad, because my terminology was misleading, and I WAS 'off topic'.. but not without reason! (as the topic had veered.. off topic :S )
    multiple starting points, interesting.. though i suppose when these converge there would still be a single recognisable starting point.. for everyone to argue over

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    how then can evolution be denied on the grounds that scientists haven't synthesised life that replicates, etc? :S surely that's more like asking what proof would be needed to damage the idea of divine creation? I guess that's the point though, since these are common rationalisations used to deny evolution..

    maybe I shouldn't concern myself with these issues after all *brain explodes*
    ...now THAT was a singularity!

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  23. Reiku Banned Banned

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    Evolution, is not a series of random events. But evolution is very random, when taking into account, the spontaneous appearance of spacetime, then taking into account our planet, with just the correct elements, and then for those elements in one off chance, to create a single celled life.
     

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