The belief that an organ so perfect as the eye could have been formed by natural selection is enough to stagger anyone.” The author? Charles Darwin. And he hadn’t even heard of pixels much less the intricacies of microstructure in the retina. But add to that rhodopsin and Darwin’s stolid faith in evolution would have met a monolithic impasse.
Rhodopsin is an essential component of a highly integrated complex molecular system. One cannot fail but sense a degree of awe when proceeding from the retina microstructure to the chemistry of vision occurring in the photoreceptors which are the rods and cones. Kindly recall the “please do” of the previous article: the next paragraph is rife with technical terms you may not understand. But again, the message is (pardon the oxymoron) simple complexity.
When light first strikes the retina, a photon interacts with a molecule called 11-cis-retinal, instantly converting it to trans-retinal. This first step, making a major change in the three dimensional structure of a molecule, occurs in the time it would take light to travel the length of the thickness of one human hair. This change in shape of the retinal molecule forces a change in the shape of the protein, rhodopsin, in which the retinal is chemically bound. The protein’s change alters its behavior. Now called metarhodopsin II, the protein binds to another protein, called transducin. Transducin now releases a small molecule called GDP and now binds to a new molecule, GTP. GTP-transducin-metarhodopsin II now binds to a protein called phosphodiesterase. This enables the phosphodiesterase to cleave a molecule called cGMP. Because the concentration of cGMP is now sensed as lowered, another complex system restricts entry of sodium ions into the cell by inhibiting the ion pump protein. This inhibits the release of the neurotransmitter glutamine which begins the signal cascade discussed under the topic of pixels.
But the system must return to equilibrium. And that would require another paragraph just as long and just as complex. You’ve gotten the message; there’s no need to persist.
Remarkably, the above process is repeated thousands of times per second in millions of cones and/or rods. So you can understand why the strident “fulfilled atheist” (his own words) Richard Dawkins in his book, The Blind Watchmaker, feels compelled to write, “Biology is the study of complicated things that give the appearance of having been designed for a purpose.”
So, what is Dawkin’s take on the eye? When challenged by fellow evolutionary biologist Stephen Jay Gould to answer: “What good is five percent of an eye?” he retorted, “Better than no vision and not as good as six percent.” And how does he know five percent of an eye works at all? He doesn’t. And it won’t. Because the chemistry we’ve described is common to all visual systems. Remember mousetraps and our tool box? Remove rhodopsin and the visual system collapses.
Rhodopsin is a large protein (348 amino acids), called opsin, inside the folds of which is located another molecule, retinal. Together, as rhodopsin, literally thousands of these molecules lie embedded as seven transmembrane segments in the bilipid membranes of the discs in the photoreceptors. Unique configurations in the beta 4 and H 3 strands hold the retinal molecule. A great deal more information could be given but suffice it to say rhodopsin is a very complex macromolecule.
And did the first precursor to rhodopsin, opsin, just, well… happen? This merits a resounding NO! To fabricate opsin requires an in-place replication system fully as complex as the retinal microstructure and photochemistry we’ve described. If you can imagine 48348, a number infinitely (no, this is not hyperbole) larger than the number of particles in the universe, you have some sense of an opsin molecule connecting the necessary amino acids in the right order simply by chance. And one protein, manufactured against a megauniverse of odds, of itself, has no function.
So, no rhodopsin? No vision. No prothrombin? No blood clotting. No DNA? No proteins. No C1 complex? No immune system. In fact, all these represented systems and a plethora more defining life itself depend on critical macromolecules which simply “don’t happen.” Nor will you find a logical step by step rationale at the macromolecular level for how these systems may have evolved applying Neo-Darwinian Theory. That’s because the science is proclaiming design: Intelligent Design. And a generation, tragically, is being instructed not to listen.
Carl Sagan, the media point person for the naturalistic world view, in his final book, The Demon Haunted World wrote: “I meet many people who are offended by evolution, who passionately prefer to be the personal handicraft of God than to arise by blind physical and chemical forces over eons of time from slime. They also tend to be less than assiduous in exposing themselves to the evidence. Evidence, for them, has little to do with it. What they wish to be true, they believe is true.”
To Carl Sagan (if he were still living): We have become increasingly aware of the evidence since molecular biology has come into its own in the 1950’s. Never has the evidence pointed so resoundingly to a conclusion as it does today. Force of logic critically applied to the information at hand permits no other conclusion: we are, in your words, “the personal handicraft of God.” King David, with far less evidence at hand than what we have, could not have expressed the response of every Christian more nobly: “I will praise Thee: for I am fearfully and wonderfully made. Marvelous are Thy works; that my soul knoweth right well” (Ps 139:14).
Homework for young Christians: recalling “No rhodopsin? No vision,” next time you read Romans, list the doctrine which is vital to the gospel of God.
