what i mean is i would not hold to these theories as though they are true, which many i have spoken with do, and scientists speak like this also, we must not become too attached to speculation of a hypothetical time, but you appear very much aware of this which is good.
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.
of course you dont HAVE to belive it, but the point is many would simply ascribe evolution to things they are studying without considering are the mechanissms actually up to the task beyond mere speculation. for instance i recently read a paper on the evolution of meiosis from mitosis and the author was talking of WHY did sex evolve and what are the advantages etc, instead of stopping and considreing is it a realistic belief to hold that sex could co evolve so many intricate mechanisms via the proposed mechanism. Many papers on and abstracts about sex consider WHY instead of HOW..
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.
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.
even if this is true, there is no other reason other then belief to suggest that any pre existing enzyme could be co opted at the "right time".
When i say need, what i mean is that if another component is not there along with certain other ones, the whole system breaks down, and therefore , since they are here now, they must have been there when they were "needed". Cells divide now, cells divided in the past, the first cell/cells divided also(this of course accordign to the common view) but for those cells to have "coevolved" what they needed to regulate that division with growth is pushing the boundaries of credulity....but you see that is exaclty what is implied since...evolutions mechanissm MUST have done it, and they are here now, so the logic goes(according to "evolutionsts") that indeed, those regulations were there since cells didnt die out and are here now!
its the same with the eye argument that i hear from everyone from dawkins to eugenie scott to textbooks and even a 2006 paper that tried to summarise everythign we "know" about the eyes evolution...essentially it was all speculation based on the "fact" that evolutions mechanisms did it...
instead of tryign to figure out how mount improbable was climbed, they should question whether the mechanisms invoked are up to the task..
i personally am wholly unconvinved by argumetns about eye evolutoin because every single one of them(at least what ive heard) trivializes the whole proccess by not even mentioning the molecular aspect and its kind of laughable they should leave that out! I also feel that peopel opposing evolution should do alot more reseach becuase all they ever talk about is teh eye and the flagellum, even ten years after they first did!
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.
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.
Do you see that a mechanism can be useful but not needed?
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.
Well, you say this but, wouldnt a DNA that has, in early life of course, supercoiled ahead of the fork(we'll assume the fork is less complex) NEED(at least in the abstract sense that if it doesnt unciold, it cant replciate and will die) a way to uncoil this? I dont mean need from a concious point of yearnig, but rather an abstract retrospective kind of way as in...
if x is not there when y is happening, organism dies...there for x is "needed" when y is occuring, there are so many systems like this in the cell i could(and may well) spend an entire therad listing them simply for food for thougth!!
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).
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.
Remember the randomness of molecular processes, and that a set of genetic information exists across a population, not as a single unit.
So the theory goes, but can this be proven? can you prove(as is claimed by a recent paper i read on the evolution of teh girrafes neck) that both the neck AND the higher blood pressure AND the heart co evolved by the mechanisms you invoke? or can you simply belive based on shoddy evidence of point mutations in bacteria...you see, the guys writing that paper are not going to question the mechanism, but rather trust that it DID do it.
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.
all your doing here is regurgitating the modern synthesis rather then questioning it. Simple question,
do you believe that orchids "hit" on both the exact look AND smell(carrion) that the flies living in the area just happened to love by these mechanisms, or can it be proven. And that other flowers unrelated also hit on these.
That flowers "happened " to produce "landing strips" leading into nectar that are only viewable in UV, which insects can luckily see in...
That an orhid "hit on" the pheromone taht makes bees think they are beign attacked, this attracts the wasps and the wasps pollinate the flowers..(P.S check out the hammer orchid, cant explain just look on youtube, amazing! i think its on a vid called sexual encounters of the floral kind)
That anitfreeze was "stumbled on" by "co opting" a preexisting enzyme just at the "right time" as the arctive sea was freezing(fish and trees have it)...as is suggested..
That a tree frog who lays her eggs in a carniverous plant doesnt lose her eggs becuase "luckily" thy secrete an enzyme neutralizing the digestive juices by pure chance.(In other words the first time the frogs did this, the juce was there, or "had to be")
That the one place where light was drastically needed, the depths of the sea...MANY creatures have INDEPENDANTLY evolved such amazing featrues,(bioluminescene) that is just pure logic, dark, needs light. why would we expect such an accumulation of mutations? we wouldnt!
That the sperm of the fruit fly(amazingly long for its body, 1000 times longer i think) just happened to "coevovle" its sperm lenght wtih the lenght of the femal ovarian tubes AND that sperm carries in it a substance that kicks the female into high gear and stops her having her usual "siesta" in the midday..
That many plants living just below water "hit on" an amazing solutoin to reach the sun....pneumatocysts! air bags along the vein of the leaf keeping it aflaot, purely genius logic..
That plants in the desert who live underground have "windows" to let the sun in to there below groudn leaves..
Or beatles in the same desert (namib deset beatle) have an amazing technological solution now being backward enginered..cant explain just read!!
http://www.asknature.org/strategy/dc...48e4e4474e7aa1 That is just stunning.
All this happened by the proposed mechanisms? is it demonstratable that those dreaded mutations could accrue in such a way?
I sound like i am simply arguing from incredulity i know this. But i hope you will understand that it is not taht i think...oh it just couldnt have happened, or that i already hold a belief that some supernatural force did it.
Rather i have, and am, constnly reading and assesing the theory and data against the evidcen and so far find it hard to even begin to beleive such a process(which i freely admit occurs and i think things like sexual selection etc are totally fascinating in how they can shape populations). can produce what we see in the natural world..especially when it relates to coevolution of parts etc..its verging on total illogic.
I am open minded and realise i know nothing compared to the experts and therefore am open to be proven utterly wrong!
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.
Yes, they are amazing. No, we'll never know the precise details of their evolutionary trajectory. Yes, they are all consistent with evolution.
Some have simple explanations - the easiest in that list is the length of fruitfly ovarian tubes.
I read some papers about directed mutations by J cairns and another i cant remmber who wrote it and there point was that bacteria seem to evolve resisttance to things, as well as teh ability to digest previously undigestibel food sources far to fast to be accoutned for by chance..
and i agree as of now...
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.
again I refer you to the italian wall lizard evolving a damn cecal valve to digest plant matter after beign taken from its island where its diet was 96 percent meat to another island with mosly plant matter. They evolved this brand new structure to digest plant matter in just 36 YEARS(wow), and it was never seen in this particular species before...of course it was used as a way to prove evolution on some forums i was visiting and to destroy creationists etc..I dont really care about that argument because, evolution has clearly occured, but it is taken on faith that random mutations "came up" with this in just 30 generations(evolutionary blink of the eye) and i find this utterly ludacris. ohthers suggest an epiginect solution, but still call it stochastic.
I advise you too check it out , the paper is on google scholar and give me your thoughts....
http://www.pnas.org/content/105/12/4792.full.pdf
Why do you find it ludicrous, specifically? I'll have a read.
Your right, it dosen't say that, and knowing this should make the wall Lizrard and other events even more unlikly.
Well you are assuming that they dont have to be neccesary, becuase indeed there are certain things that occur in the cell that could not happen withotu other neccesary components..meiosis for instance requres multiple co working functions as stated in a very good paper about the evolution of it..
"While meiosis almost certainly evolved from mitosis, it has not one but four novel steps: the pairing of homologous chromosomes, the occurrence of extensive recombination between non-sister chromatids during pairing, the suppression of sister-chromatid separation during the first meiotic division, and the absence of chromosome replication during the second meiotic division. This complexity presents a challenge to any Darwinian explanation of meiotic origins. While the simultaneous creation of these new features in one step seems impossible, their step-by-step acquisition via selection of separate mutations seems highly problematic, given that the entire sequence is REQUIRED(my emphasis) for reliable production of haploid chromosome sets"
not my words...
http://www.genetics.org/content/181/1/3.full
and this is just the tip of the cellular iceberg, if you want i could name many thigns that simply do not work without other components present..hence the constant suggestions of "co evolution" of these kinds of problematic parts, which is pure speculation.
I just feel we need to question more and actaully study that wtih which we are accusing the mechanisms of "creating".
I just feel we need to question more and actaully study that wtih which we are accusing the mechanisms of "creating".
I am open minded and realise i know nothing compared to the experts and therefore am open to be proven utterly wrong!
What you're talking about seems to be the idea of
irreducible complexity.
I'll have a look at the meiosis evolution paper.