Remus said:
Oh good grief, of course not. I was using an exaggeration to illustrate how the overly simplified the description of the change is. Is this what I get for spending time on this with you? Is it impossible for you to give anyone that doesnt agree with you some credit?
Sorry about that. Its just that one meets people that do think that way too often.
No, you don't get "a simple lens". You get a translucent layer that blocks light.
A translucent layer doesn't block light per se. It blocks images. All one can see is light and shadow.
You do realize that your argument is still "it could happen" don't you? I'm still waiting for the science to begin, so whenever you're ready.
Determining whether it could happen is a legitimate scientific project in itself. It tells us whether it is worth the effort to find out how it happened. If we discover that the mechanism we think capable of producing complexity is, in fact, not capable of producing complexity, we know there is no point in following that line of research any further. If it
can't happen by evolution, we know it
did not happen by evolution. But if it can happen by evolution, it may be worth the effort to figure out how it evolved.
My impression is that you have concluded not just that complex features did not evolve, but that that they
can't evolve, so that
is the issue. How did you come to the conclusion that evolution is incapable of producing complexity? Not this one instance or that other instance of complexity, but any complexity.
After all, if evolution is capable of producing any complexity at all, then it is capable of producing any one instance of complexity whether or not we know exactly how it did in any one case.
Are you trying to change the subject? I honestly dont know how many. Are you going to claim that you do know while we are in the infancy of studying the origin of genetic sequences?
No and yes. Still the same subject. The point is that scientists probably don't know yet either. A ball park guess might be anywhere from a few dozen to several hundred. And we are not even talking about the origin of genetic sequences. We are just talking about finding out what existing genetic sequences do.
It is only recently that the human genome has been sequenced. Finding out what each gene in that sequence does (if it does anything) will be an enormous task that will keep geneticists busy for decades to come. And that is just the human genome. There are millions of other genomes waiting to be sequenced. And a good many of them may also be relevant to the evoluton of human genes.
Furthermore, in the case of the lens of the eye, even when a sequence is identified as regulating the formation of the lens, the actual impact has to be determined. And the extent of the impact of that gene relative to other genes which also impact the formation of the lens. Does a particular gene work with others to give an additive effect? How much of the effect is due to the contribution of this gene? 1%, 10%, 0.1% ? And what are the parameters under which the gene is expressed? For many genes these are all questions still to be answered.
So, it is very much premature to get an exact history of each gene so that the exact evolutionary pathway of the lens of the eye can be traced.
On the other hand, what do we know already?
We know that everything in the body is regulated by genes.
We know that genes mutate.
We know that some genetic changes are reflected in phenotypic changes.
We know that some phenotypic changes stay in the genome and become fixed in the species.
We also know that the relationship between gene and phenotype is complex even when we are dealing with a scenario of one gene->one characteristic.
The gene/phenotype relationship is even more complex when you have varying instances of many genes->one characteristic or one gene->many characteristics.
We know that environmental factors, mating choices, gene flow and genetic drift also affect the survival of specific phenotypes (and therefore of the genes that yield those phenotypes.)
So when we have a complex feature, we also know that there is a lot of complex behaviour at the genetic level that affects it. Is this not the science needed to determine if the mechanism is adequate? to determine if it could happen?
It seems to me that what you are saying is that unless we can show the exact evolutionary pathway of every gene that regulates the development of the lens of the eye (or any other complex feature), we have no way of judging whether the mechanism can function at all. Is that indeed your position? Why do you take that position?
We know the mechanism can function. We know that genes mutate. We know that genetic innovation is the basis of phenotypic variation. We know that natural selection functions to drive populations toward a form, physiology or behaviour that is better adapted to the current environment.
So why, with all the evidence we have about the capability of the mechanisms of evolution, would we assume it cannot meet the challenge of evolving a complex form without a logical or evidential reason to do so? Given that there are probably at least a dozen, and possibly hundreds of genes (not yet identified) affecting the formation of the lens of the eye, that all told there have probably been hundreds of thousands of mutations in these genes, and that the best improvements have benefitted from positive natural selection over millions of years what is the basis for concluding that this complex web of genetic behaviour did not produce a complex feature like the lens of the eye?
At the very least, why would we close off the possibility? What is the basis for concluding there is insufficient grounds to explain complexity via evolution?