- The eye evolved precisely 544 million years ago
- The eye evolved in a period of 500 thousand years in a series of tiny steps, with each step producing a species mean that was fitter than the one before
- That the impetus for this natural process was probably a rapid increase in the intensity of sunlight
Friday, February 14, 2014
Additional Review of "In the Blink of an Eye"
Andrew Parker’s book In the Blink of an Eye was the subject of an earlier review post on this blog. I had intended to come back and do two more posts. Alas, way led on to way and I never got back. I’m finally circling round, however, and will do at least this one more post about it.
The premise of Parker’s book is that the evolution of the eye, long thought to be a very weak link in the evolutionary chain, because of the length of time that it would take, could in fact have happened in about 500,000 years. Which is, in evolutionary terms, just the blink of an eye. He says this happened at the beginning of the Cambrian Epoch, which would have been approximately 543 million years ago.Well, actually, according to Parker there’s no approximate about it. Dating of fossils is so exact that he says it took place exactly then, give or take a million years. This corresponded with what scientists call the Cambrian Explosion, which was a rapid increase in the number of species in a short amount of time (evolutionary speaking). Other things taking place at that time, in addition to species suddenly having eyes, is the sudden appearance of hard body parts and eyes. All the phyla we know now are found in fossils know to be after the explosion, but not in fossils known to be before the explosion. Parker says this happened precisely 543 million years ago. It was the sudden evolution of eyes, he says, that caused the need for animals to evolve hard body parts, which in turn gave rise to the explosion in the number of species, all because eyes changed the whole relation of prey and predator.
The book goes on, in great detail, to state what happened at that time, as determined from the fossil record. Finally, toward the end, Parker gives us his view on the why: “Why it happened is the puzzle this book sets out to solve.”Those who doubt evolution say this explosion would correspond to certain parts of the Creation account in the book of Genesis. Parker and his peers would reject this (though see his book The Genesis Enigma for a lengthy discussion of the Genesis account of creation), saying that God, if He really exists, had no part in any creation of all things animal, vegetable, or mineral. Everything had to happen by natural causes.
On page 224, Parker begins his discussion on the rapid evolution of the eye. First a patch of light-sensitive skin occurs, for whatever reason. Mathematical modeling done has shown that, from that small patch of light-sensitive skin, 364,000 generations would be needed for a fully developed eye to evolve if the rate of evolution were just “0.005 percent from one generation to the next.” He then says this is pessimistically slow, and that a much faster rate of evolution is likely. Based on the life span of the species living 544 million years ago, those generations would pass in about a half million years. The 0.005 percent change per generation was based on a light-sensitive patch of skin changing in length, width, or protein density by 1 percent for each generation.But, what I don’t get is why evolution should happen at 0.005 percent from generation to generation. Does evolution happen from “adaption”—that is, the slow process of survival of the fittest then breeding offspring who are even more fit—or does it happen by “mutation”—the sudden, unexplained occurrence of a change in the animal that just happens to be fitter than a non-mutated offspring?
Say that a larger animal is fitter than a smaller animal, because it will win a fight between the two. Or it will have more success in predation, and thus will live longer and breed more often, and it’s offspring will be more likely to be like it than like those smaller/weaker members of the species at the opposite side of the bell curve. In any species I suppose no two critters are exactly alike. There will be a range of sizes, for example, with some kind of distribution around a mean or average. Those few of the species who are a standard deviation or more above the mean will have greater success at predation and living and breeding. After some generations of this, the mean will change; it will be larger/stronger/fitter. But the species preyed upon will be adapting too, and will have a new mean after those generations and be fitter to fight off the predation of the other animals.Now, the animals in question don’t will this to happen, as I understand evolutionary theory. The stimulus to adapt must come from external pressures, not internal causes. They don’t say, “Our species has to grow larger and stronger or we won’t survive. Let me produce larger and stronger offspring.” It takes place through natural selection based on success and failure of the various members of the species. Over a long period of time the specie changes or, as evolutionists believe, a whole new species develops.
This idea that evolutionary change by adaption should take place in nice 0.005 percent steps seems to me to be ridiculous. It assumes that at each change the species is fitter than it was before the change. Parker says that is obviously true, but it’s not obvious for me.So, while I enjoyed this book and took in a lot of information, I am not persuaded by the conclusions, which are: