HT: RLC

The Findings of Research

Research by ophthalmologists has clearly shown why the human retina must employ what is called the "inverted" design. An inverted retina is where the photoreceptors face away from the light, forcing the incoming light to travel through the front of the retina to reach the photoreceptors. The opposite placement (where the photoreceptors face the front of the eye) is called a "verted" design. One of the many reasons for the inverted design is, behind the photoreceptors lies a multifunctional and indispensable structure, the retinal pigment epithelium (Martínez-Morales 2004, p. 766). This monolayered tissue contains the black pigment melanin that absorbs most of the light not captured by the retina. This design has the very beneficial effect of preventing light from being reflected off the back of the eye onto the retina, which would degrade the visual image.

The photoreceptors (rods and cones) must also face away from the front of the eye in order to be in close contact with the pigment epithelium on the choroid, which supplies the photoreceptors with blood. This arrangement allows a "steady stream of the vital molecule retinal" to flow to the rods and cones without which vision would be impossible (Kolb 2003, p. 28). The verted design, claimed by Miller to be superior, would place the photoreceptors away from their source of nutrition, oxygen, and retinal (the choroid). This design would cause major problems because rods and cones require an enormous amount of energy for their very high metabolism required in functioning, maintenance, and repair. In addition, because of phototoxicity damage, the rods and cones must completely replace themselves approximately every seven days or so.

The photoreceptors and retinal epithelium absorb an enormous amount of light on a continuous basis when the eyes are open. Because the light is converted largely into heat, the retina must have a very effective cooling system, again provided by the choroidal blood supply directly behind the pigment epithelium. If the pigment epithelium tissue were placed in front of the retina, sight would be seriously compromised. Reversing the retina so that it faces away from the pigment epithelium would also compromise sight to the degree that sight would be impossible because the photoreceptors must be embedded in the retinal pigment epithelium to obtain the nutrients required to function.

This design is extremely critical because the retina requires a high metabolism level due to the continual replacement of the photoreceptors required for vision. Consequently, the retina uses more oxygen and nutrients than almost every other part of the body, requiring an ample blood supply. The verted design would not allow the rods and cones to function properly because of the blood supply required for their high rate of metabolism. If the photoreceptors were in front of the neurons, the blood supply would have to be either directly in the light path of the receptors, or on their side, which would significantly reduce the number of photoreceptors used for sight.

Importantly, placing the retina neural components in front of the photoreceptors does not produce an optical handicap for several reasons. One reason is the neural elements are separated by less than a wavelength of light. Consequently, very little or no scattering or diffraction occurs, and the light travels through this area as if it was at near-perfect transparency. Secondly, when viewed under the microscope, most cells are largely transparent (and it is for this reason stains, such as Eosin-Y and Hematoxylin 2, are needed to better visualize the various cell parts). Consequently, the thin layer of cells in front of the retina rods and cones have a negligible light blocking effect.

In the retina region which has the highest resolution, the central retina (the fovea and, in particular, the foveola), the neurons in front of the photoreceptors are shifted to the side so that light has a direct pathway to them, resulting in the least distortion where it matters most. The high resolution macula also uses cones that are more tightly packed to achieve high resolution color vision. The peripheral retina has lower resolution and consists of mostly rods for black and white vision.

This design is a highly effective method to accurately transmit enormous amounts of data along the optic nerve in a method analogous to the zipping and unzipping of a computer file to facilitate computer file transmission. To function, the transmission must be very rapid because the image needs to be refreshed continuously like a pixel TV image. The eye's design actually appears to be optimized around the physical limits of the visible light spectrum (Calkins 1986).

The pigment epithelium tissue performs numerous other functions critical for retina viability and activity. One is that it phagocytosises ten percent of the mass of each photoreceptor outer segment on a diurnal schedule, and constantly restores the chromophore to 11-cis-retinal from its all-trans configuration, permitting visual pigment synthesis and regeneration (Dowling 1987, p. 198). It also is part of the outer blood-retinal barrier, helps maintain water and ion flow between the neural retina and the choroid, protects against free radical damage, and regulates retinoid metabolism (Martínez-Morales, et al., 2004, p. 766).

At the end of the piece recent advances in knowledge are noted. That reminds me of an adage. Something about science being a self-correcting process even if that includes correcting the misunderstanding of ID critics.

It is also a cliche well suited for those who would presume to know the thoughts of another or simply ignore well known theistic views in the interest of maintaining their own prejudice and the comfort zone that theological ignorance affords them. Most of those who believe in God attribute the origin of all natural laws and natural phenomenon to God. They do not look for gaps thinking that God is detectable in them. That's the straw man that defines the mindset of critics.

But the most interesting aspect of the cliche is how it is used to hide a sleight of the materialist hand. If materialism is to maintain the fiction that it is sustained by scientific data then it must at least attempt to separate empirically derived assertions from assertions not sustained by empirical data. To assume favorable data exists and has not yet been found is to demonstrate faith in an outcome in lieu of an empirically grounded argument. It also places a philosophical bias into an unknown and asks that discernment be averted in the interest of maintaining an unverified expectation. Don't mention the inadaquacy of evidence or the fact that the emperor is wearing no clothes.

The development of higher forms of life would appear to have been influenced by RNA polymerase II. This enzyme transcribes the information coded by genes from DNA into messenger-RNA (mRNA), which in turn is the basis for the production of proteins. RNA polymerase II is highly conserved through evolution, with many of its structural characteristics being conserved between bacteria and humans.

If enzyme possibilities for initial front loading were nominated RNA polymerase II would likely be a popular candidate. Found in organisms as diverse as bacteria and humans this enzyme plays an important role in gene transciption. In eukaryotes an enzyme structure dubbed the carboxyterminal domain or CTD is involved in gene expression. There is variation in amino acid sequence among different eukaryotic organisms. Interestingly, a form of splicing during transcription enables multiple variants in proteins from a single gene.

here

Timelines have a starting point. That would involve a biological entity able to replicate itself. Once that condition is present it is assumed that natural selection sufficiently explains subsequent changes. Yet more than an unknown starting point needs to be recognized. A symmetry break between physical properties and function is noted as is the insufficiency of natural selection based theories to bridge a gap between a prebiotic environment and a biological reproducing entity. At one point in time there is no self-replicator and no specification criteria. Then there is both. That is the moment correlating to initial front loading. The difference between IDists and their critics is the belief by the former that intelligence accounts for loading of the replicating information storage unit.

But it may also be that natural selection is credited with more of a role than merited even when biological organisms are present. At least the logic that common ancestry requires natural selection is doubtful according to the PNAS paper: Did Darwin write the Origin backwards? The abstract:

After clarifying how Darwin understood natural selection and common ancestry, I consider how the two concepts are related in his theory. I argue that common ancestry has evidential priority. Arguments about natural selection often make use of the assumption of common ancestry, whereas arguments for common ancestry do not require the assumption that natural selection has been at work. In fact, Darwin held that the key evidence for common ancestry comes from characters whose evolution is not caused by natural selection. This raises the question of why Darwin puts natural selection first and foremost in the Origin.

Reference:

1. Intelligent Design; William A. Dembski; Page 149; InterVarsity Press; 1999.
2. Ibid.

Crispian Jago, an IT consultant, is hoping the experience will enrich his two children.

“I’m very keen on not indoctrinating them with religion or creeds,” he said this weekend. “I would rather equip them with the tools to learn how to think, not what to think.”

But there is also this:

While afternoons at the camp will involve familiar activities such as canoeing and swimming, the youngsters’ mornings will be spent debunking supernatural phenomena such as the formation of crop circles and telepathy. Even Uri Geller’s apparent ability to bend spoons with his mind will come under scrutiny.

Debunking supernatural phenomenon heh. Most assuredly this will be done by teahing children how to think rather than what to think.

And there is this objective appraisal:

“We are not trying to bash religion, but it encourages people to believe in a lot of things for which there is no evidence.”

No evidence. Beware when people cite an absolute value like zero as an evidentiary descriptor. Even when I disagree I tend to be more generous with my opponents but then again I'm more objective too. But what is the evidence that sustains the position that there is no God?

Oh well, there is this too:

While afternoons at the camp will involve familiar activities such as canoeing and swimming…

So let's hope for the best. For the sake of preventing child abuse of course.

This assembly maps involves 15 universal small subunit ribosomal proteins, and of these 15, ten have a moonlighting role (we shall explore several of these functions at a future date). What’s striking is that all proteins involved in binding to the 3’ domain of the rRNA are not only universal proteins, but also have moonlighting functions.

In other words 2/3 of the proteins have moonlighting roles. Quite a large percentage. Darwinian evolution predicts that some ancient proteins will be coopted for future uses, but 2/3 of them? What is even more intriguing about Mike's post is his prediction:

Those universal ribosomal proteins that don’t seem to have a moonlighting role are s17, s5, s8, s11, and s15.

Thus, the front-loading hypothesis further predicts these too will eventually be discovered to have moonlighting functions.

Anyone care to predict that he's wrong?