The specific details of the evolution of specific mechanisms is speculation.
But the theory itself, that complex mechanisms can develop through gradual change... that's something that that seems consistent with everything we observe.
So yes, we speak of evolution as if it as if it's true.
yes, evolution is true i agree. But what evidence do we have that mutations can ACCRUE to produce anything usefull, let alone those adaptions we actually see in nature, or for that matter coevolution of parts.
or something as logical as looking EXACTLY like a leaf etc..
there is no reason to expect such complexity, why not stay lookign a bit like a leaf, or just gree? people seem to think that, once you look a bit like a leaf then the magic of selection takes over and propels you to ever higher complexities. when infact the mutations must occur first over many many many generations before they are "selected"..
i dont see the evidence that complex mechanisms can evolve through(evolutions proposed mechansims) gradual change?
Only that certain mutations may on very rare occasions express a protein differently etc thereby giving an adavantage, its quite a large leap to go from to extrapolating ontop of the compelx mechanisms(actaully nature much more then compelx, its co ordinated) we see...
Yes, of course. That's what people do as a matter of course.
When you're evaluating a car, you don't need to know the specifics of how the iron was mined.
your car analogy is good, but of course it dosent hold up in a sense because many scientist indeed ARE tryign to find out how particular pecies of the car(organism) came to be, or how they evolved etc. many others simply presume its origin and go from there instead of reevaluating the power of the mechanisms(have you ever seen a paper that evaluates the mechanism as applied to nature? id love to see it.)
It seems to me that you're looking for answers to questions that can't be answered except by speculation, and complaining when people speculate about those answers.
I assure you im not simply "complaining"but inquiring heavily since,as you can proberbly tell, i am not yet convinced..nothing wrong with speculation either, once is based on somethign solid.
so they cant be answered, I agree, but does that mean we should presume HOW it happend? again What is the evidence that mutatios can accrue to produce complex co ordinated systems? and co evolution of those systems?
There is plenty of evidence of enzymes performing more than one function, so yes, there is good reason to believe that prexisting enzymes can be coopted into enabling new functions.
again, accidental co option of enzymes(got a few examples?) is not good evidence that certain enzymes in the past must have been coopted in a coevolution, otherwise they would not have worked..for instance DNA polymerase is actually held onto the DNA via a mind blowing CLAMP complex that is a ring shaped protein attachign DNApolymease to the DNA itself. But of course the ring shaped clamp is useless on its own(unless we make up hypothetical uses for a ring), it must be LOADED onto the dna by the clamp loader via atp hydrolises...but of course something amazing was discovred about the structure of this clamp, the grooves within its ring MATCH the grooves of teh dna? so it fits like a screw mechanism!!. the ring then bind polyemrase and flies forward a 1000 ntides persection in eucaryotes!
amazingly because the laggign strand must be synthesised bit by bit in okazaki fragments due to both the antiparallel nature of DNA's prime ends and the unidirectionallity of polyerase..this clamp has to be constanly loaded on and of on and off on and off while moving this fast.
first of all its like something out of a sci fi movie and when i try to apply gradual accidental changes to its development i simply hit wall of incredulity!
second, seeign a few mutations causing enzymes to have novel functions does not accout for the fact that in the past, many of these functions would have to be present simultanesouly...i mean, what came first, clamp or clamp loader, how can those grooves that fit the dna gradually evolve?
since if the clamp doesnt fit dna, its game over...it even has a gap between 2 of its sub units to let the spiraling helix escape as the clamp moves forward! if the gap wasnt there?
how can we simply, in one breath admit, we can only speculate, but in the other claim there is good evidence for the "origin" or "co option" of these mind numbing systems..(of course this all leaves out regulation and transferases as applie to these clmaps)..intersting the clamps are uqiquitous across all life, does this mean(this is a question) that we would assume it evolved multiple times? if so.....holy shit!
again, this is arguing from incredulity, but not becuase GOD DID IT.
But becuase as i become aquainted with the mechanisms given the task, the task seems less and less plausible...
I know what you mean by need. What you seems to be missing is that evolution theory says that if some mechanisms existed before it was needed, then that mechanism must have been useful before it was needed.
yes, because it MUST say that, otherwise it would totally implausible for such systems to "arise", how does saying other systems MUST have been usefull even begin to prove the mechanisms of evolution?
I personally dont know how it happened, and i am open to all opinions, even the ones you suggest(and science of course) but only when i see sufficient reason to do so.
Do you see that a mechanism can be useful but not needed?
indeed i do, but i dont really see what this says?
With eye evolution, you are again looking for details that can never be known. All we can do is speculate of possibilities - and yes, such speculation is useful because it does indeed show that the mechanisms of evolution are potentially up to the task.
this is what irks me(not you), that, as you have rightly said, we indeed have only speculaition as a tool to probe such matters(and imo, flimsy evidence)..but at the same time those who question it are looked down on and there threads get moved(case in point!)..
Indeed how can we say evolutions mechanisms are up to the task if all we can do is speculate, mutations have never been shown to accrue to produce something even a millionth as complex as an eye so what is wrong with being utterly skeptical of such assertions(and indeed there are those popularizing science such as dawkins and millar who insist this is how it happened...) they dont even consider(that ive seen) that it could be utterly wrong!
Not necessarily. If a particular DNA sequence sometimes supercoils on duplication and sometimes does not, then it can replicate without a topoisomerase mechanism (ie it doesn't need it), but it will do so more successfully with a topoisomerase mechanism (ie it can use it).
first off, this is speculation of course. nothign wrong wtih that just pointing it out..
now, if there is evidence of DNA uncoiling itself id like too see it for sure.
helicase is required in modern DNA to uncoil ahead of the fork as well as SSB's(single stranded binding proteins) to protect the exposed backbone(amazing!), so indeed if a past dna could sometimes uncoil itself it would be almost ahead of its time!
but of course without SSB's the hypothetical back bone of this DNA would be in deep trouble considering the enviroments it was in...
either way, there was a time in the past(following evolutions path here ) that topo was "coopted", my qualm is
A...could this actually occur via the mechanissm
B...could it happen "on time" for when dna could not able uncoil itself by "vibrating"..
cant you see the sheer amount of things that need to be there at one time simply to replicated dna, simply to get moving along it, and the amount of separate proteins(even assuming they are much less numerous and much less conplicated then today, although im assuming we have no fossil proteins so we dont really know if thats true?) required to be moving at the SAME SPEED, if helicase goes too fast behind the fork, crash, if topo, or its hypothesised gyrase ancestors didnt move the same speed as the rest of the forks holoenzyme, and especially the helicases then houste we have a problem!!
sorry bout the long answers!
I suspect (but don't know) that supercoiled DNA with at least one free end may untangle itself through random vibrations. Againm such DNA doesn't need topo, but will replicate faster with it.
oh having one free end would certainly not uncoil DNA, as it is bound so tightly that boiling water is required to loosen it without helicases..interstingly there are usually more then one free end in modern DNA, yet topo is required
its like pulling a rope tighter, there will always be free ends on both prime ends, but once you get to a certain tightness(dna is already supertight without supercoilding!) then it will not uncioil itself, not a chance.!(of course i am open to evidence to the contrary)
No, it can't be proven. All that can be said (as with any theory) is that it is consistent with what we observe. Not shoddy evidence, either, despite what you might have read elsewhere.
you say there is evidence? what is the modern evidence that such a coordinated evolution of parts is possible..
For me, at the minute, it is actaully the best case against the mechanisms(co evolution of parts i mean, which is, ubiuitious throughout nature!) this is of course skipping over the fact that its leg skin is pulled supertight to stop its vessels bursting(co evolution?) and it has an amazing system to stop its head vessels exploding in its headd when it bends down(co evolution?)...
people alwasy say, sexual selection made the neck longer as if that explaisn all this!
You give lots of examples of amazing developments... but the whole point of evolution is that it's only the successful developments that survive. So we obviously don't see orchids that don't get pollinated, fish and trees that can't survive in their environment, frogs whose eggs are eaten by carnivorous plants, fruitflies who can't inseminate or be inseminated, plants living underwater or underground that can't survive there, beetles that live where they can't get enough water, or whatever.
and yet, the mechanisms can explain it?
if we dont see all those "defective" organisms you have named then why not? if evolution is an ongongi process, and they existed in the past, then why not now?(this is not a big problem or part of my argument and i likely made a silly mistake but im just inquiring)
Yes, they are amazing. No, we'll never know the precise details of their evolutionary trajectory. Yes, they are all consistent with evolution.
yet, that evolutionary trajectory WAS through the proposed mechanisms?
they are consistent with change over time, thats it..
since all of them would reqiure the accumulation of MANy beneficail mutations over long time periouds then i dont see the evidence we have for this accumulation..
Some have simple explanations - the easiest in that list is the length of fruitfly ovarian tubes.
care to explain? i'd certainly be intersted
That's an important claim, and one that can be directly tested.
But it's also important not to make judgements of probability by intuition - our intuition is woefully inadequate for that task./
very important claim indeed, and your right I jumped the gun saying i agree, but it is very intersting!(for the life of me i cant remember but recently i read an amazing article about a gene in ecoli called LEXA i think, and this may match into the directed mutations theory somehow..
when the researches deactivated this gene, the organism NO LONGER UNDERWENT MUTATIOS AT ALL, not even when exposed to radiation!!
could this be a built in adaptions mechanissm to respond to the enviroment?
pure specualtion but quite intersting, check it out if you want )
Why do you find it ludicrous, specifically? I'll have a read.
I'll answer this below.
What you're talking about seems to be the idea of
irreducible complexity.
I am not tryign to prove IC, if that somehow rears its head then i cant help it, im just following my own line of inquiry but i neither think that IC disproves evolution or that it is prove of a Designer.
I'll have a look at the meiosis evolution paper.
