The Science of Evolution

Sigh....FINALLY. I finally found the facts I need to feel good about my decision to give up religion. Because of a recent exchange with one of my Christian friends, I'm doing more research on exactly what category of misfits I fall into....atheist or agnostic. More on that later. Today Chris and I were watching a PBS Nova special on Intelligent Design, which is the belief that an intelligent being had something to do with the creation of the universe. The documentary focused on the battle at a Dover, Pennsylvania school where the conservative, religous board wouldn't allow a new science textbook because it discussed in great depth the theory of Evolution. First, let me say that Evolution is still a theory, however, it has yet to be disproved. Intelligent Design is not scientific, is not a theory, and is just one more way that religious fanatics are trying to work the belief in a higher power into the education curriculum of our young people. Let me remind my small audience again of the separation of church and state.

Featured in the documentary was the legal battle between Evolution and Intelligent Design. One of the featured scientists was Dr. Kenneth Miller. In summary, he explained the scientific bridge between apes and humans. In studying the fossils of the world, many scientists have been able to bridge the gap between sea-dwelling and land-dwelling animals and ballpark the time period in which sea-dwelling animals evolved, grew legs, and moved to land. But the gap between apes and humans always remained wide open. Below is an excerpt from Dr. Kenneth Miller's discussion. I'm not posting this so you may abandon your faith, I'm posting it so you can understand why I am who I am and why religion, to me, means nothing.

Common Ancestry:

Q: People often say, "I'm not descended from a monkey." What's the true relationship there?

Miller: Well, I often hear people say that they're not descended from monkeys, and they would defy me or anybody else to show that they are. Well, they're right, they're not descended from monkeys. They're not descended from chimps or monkeys or gorillas or any other living organism.

The essential idea of common ancestry is that ultimately all living things on this planet share common ancestors if we go far enough back into the past. So, for example, to take the case that people talk about all the time, we share a common ancestor with all primate species. This means that we're related, by having a single ancestor somewhere in the past, to monkeys, gorillas, chimpanzees, and so forth.

But the idea of common ancestry goes way deeper than simply saying we're related to monkeys. We're in fact related to all mammals. You go farther back, we are related to all vertebrates. And, ultimately, we are related, if you go far enough back, to every living thing on this planet. The almost universal nature of the genetic code, the fact that all life depends upon DNA, all of these things are evidence of this commonality of ancestry, if we go far enough back in time.

Q: One of the lines of evidence that you pointed out at the Dover trial is the organization of our own chromosomes. How is that evidence for common ancestry?

Miller: We've known for a long time that we humans share common ancestry with the other great apes—gorillas, orangs, chimps, and bonobos. But there's an interesting problem here. We humans have 46 chromosomes; all the other great apes have 48. In a sense, we're missing a pair of chromosomes, two chromosomes. How did that happen?

Well, is it possible that in the line that led to us, a pair of chromosomes was simply lost, dropping us from 24 pairs to 23? Well, the answer to that is no. The loss of both members of a pair would actually be fatal in any primate. There is only one possibility, and that is that two chromosomes that were separate became fused to form a single chromosome. If that happened, it would drop us from 24 pairs to 23, and it would explain the data.

"The closer we look at our own DNA, the more powerful the evidence becomes for our common ancestry with other species."

Here's the interesting point, and this is why evolution is a science. That possibility is testable. If we indeed were formed that way, then somewhere in our genome there has to be a chromosome that was formed by the fusion of two other chromosomes. Now, how would we find that? It's easier than you might think.

Every chromosome has a special DNA sequence at both ends called the telomere sequence. Near the middle it has another special sequence called the centromere. If one of our chromosomes was formed by the fusion of two ancestral chromosomes, what we should be able to see is that we possess a chromosome in which telomere DNA is found in the center where it actually doesn't belong, and that the chromosome has two centromeres. So all we have to do is to look at our own genome, look at our own DNA, and see, do we have a chromosome that fits these features?

We do. It's human chromosome number 2, and the evidence is unmistakable. We have two centromeres, we have telomere DNA near the center, and the genes even line up corresponding to primate chromosome numbers 12 and 13.

Is there any way that intelligent design or special creation could explain why we have a chromosome like this? The only way that I can think of is if you're willing to say that the intelligent designer rigged chromosome number 2 to fool us into thinking that we had evolved. The closer we look at our own DNA, the more detailed a glimpse we get of our own genome, the more powerful the evidence becomes for our common ancestry with other species.

To read the full article and more about this documentary, please visit PBS:
http://www.pbs.org/wgbh/nova/id/defense-ev.html