The claim of the evolutionist is that the vertebrate eye would be better fitted to life if it were created by an intelligent source. Since I suppose you would consider yourself intelligent (as opposed to the brute force of natural selection), please support this claim with evidence that there is a better design to be found that man would be capable of creating.
Um, God is supposed to be a lot better at creating than man, so I don't see why human engineering is relevant.
I'll discuss the rest of the eye issue in response to another of your posts.
I'll admit I may have been wrong in asserting that the origin of DNA is "impossibly circular". But what about the origin of
DNA repair enzymes? They require DNA information to exist, yet they repair errors in DNA which would then rely on the repair enzyme. So this, I believe it would be safe to say, is at least almost impossibly circular.
Why? Let's first establish that the first DNA genomes would have been tiny compared to the genome of any cellular life form. They would have descended directly from RNA genomes, and RNA genomes can't grow large because of the reactivity of RNA (and, at this point, the lack of substantial repair).
DNA does spontaneously get altered, but, being more chemically stable, it does so less often than RNA (it doesn't break nearly as often, for one thing). So unrepaired DNA is still an improvement over RNA, and allows for larger genomes (compare the genome sizes of RNA and DNA viruses). Larger genomes provide room for new genes - among them those that code for repair enzymes. These are another improvement, now that the cell can afford them - with repair, it'll acquire fewer mutations, and more of its descendants will do well. Repair enzymes in turn allow for even larger genomes, yet more genes... and with a good enough set of them, the road to (nearly) endless forms is open.
By the way, Sarfati's article is very misleading in places. Where he says that "about a million DNA 'letters' are damaged in a cell on a good day", he doesn't say what species he's talking about, but I'd bet a fair sum that it is humans. (I'm also slightly suspicious of the number, but I don't have my relevant notes here to check) The human genome is several orders of magnitude larger than the first DNA-based life forms' would have been, and to top it, it resides in relatively long-lived cells in a phenomenally long-lived and slow-reproducing organism. We
need to maintain that DNA, or it would be in ruins by the time we reproduce. To a protocell that produces descendants every few minutes, losing some of them to DNA damage is much less of a problem. These protocells also start out in a world where
no one has repair mechanisms, so the competition is even.
And this is only beginning to get into the problems of the origin of the first living cell, something not required of evolution, per se, but of the atheistic evolutionist nonetheless.
Oh, you really should watch the first video in the Origins series (
The Origin of Life). The scenario it describes is nothing short of neat. The best thing is, a lot of it is based on known chemistry, not speculation.
(Sorry, I can't help it, I'm a huge fan of cdk's videos. The effect of good science explained with pretty visuals, I guess :o)
But it's not that easy. Consider the two alternatives to the current setup:
See a quote from
this article:
Regenerating photoreceptors
Someone who
does know about eye design is the ophthalmologist Dr George Marshall, who said:
The idea that the eye is wired backward comes from a lack of knowledge of eye function and anatomy.
1
He explained that the nerves could not go behind the eye, because the choroid occupies that space. This provides the rich blood supply needed for the very metabolically active retinal pigment epithelium (RPE). This is necessary to regenerate the photoreceptors, and to absorb excess heat from the light. So the nerves must go in front rather than behind. But as will be shown below, the eyes design overcomes even this slight drawback.
In fact, what limits the eyes resolution is the
diffraction of light waves at the pupil (proportional to the wavelength and inversely proportional to the pupils size); so alleged improvements of the retina would make no difference to the eyes performance.
The greatest design flaw is not the resolution of the eye - heck, does any eye have better resolution than a raptor's? It's the presence of a blind spot. Sure, you can't sense that you have one unless you look for it, but that's because brains are good at pretending that such gaps don't exist. You wouldn't need a blind spot if the optic nerve didn't have to collect axons coming from the other side of the retina. And it's perfectly avoidable, cephalopods are living proof.
Its important to note that the superior design of Dawkins with the (virtually transparent) nerves behind the photoreceptors would require either:
- The choroid in front of the retinabut the choroid is opaque because of all the red blood cells, so this design would be as useless as an eye with a hemorrhage!
- Photoreceptors not in contact with the RPE and choroid at allbut without a rich blood supply to regenerate, then it would probably take months before we could see properly after we were photographed with a flashbulb or we glanced at some bright object.
Do octopuses have either problem? Certainly not the first...
It's interesting that the article talks about the "superior" designs of Dawkins as if they were hypothetical, when non-inverted retinas are found in many living animals (not just octopuses - figure 5 in
this paper illustrates fairly complex "everse" eyes from a segmented worm and a snail, for example)
Besides, there's what, two, three layers of neurons connected to the retina? Granted, physiology isn't really my cup of tea, but that doesn't sound that far for stuff from blood vessels to travel. And couldn't you thread some capillaries
among the neurons? Do the cell bodies even have to sit near the photoreceptors?
(BTW, again based on the diagrams in Arendt and Wittbrodt 2001, cephalopods don't have a RPE as such. Instead, pigmented cells are embedded between the photoreceptors. So in a sense, their retina can't
not be in contact with the RPE. Why is that not an option for vertebrates?)