A Conversation on Evolution

Interesting that just as I started talking about evolution in my blog, it came up over dinner. The Linehans and Gabby basically had the same questions as everyone else, and while I can't claim to be anywhere near an expert, I offer up the gist of the convo for your contemplation.

From what I understand so far, the theory of evolution as it exists in Biology today rises from two important, consistently verifiable observations. The first is famous because Darwin observed it the best, namely the effects environment have on a population of any given species over time. He saw it happen in the Galapagos Islands (sp?), where the same species of finch had been separated and isolated on different islands with different environments, predators and food sources. Over the course of several generations those birds that had physical features best adapted for survival in their new environments came to dominate the gene pool of that population, because those that survived were the ones that could produce offspring. Even if we ignore for now the supposed difficulties in genetics, this pattern is something we can observe in nature over and over again. The best example I can think of is the HIV virus. Like all other viruses, it reproduces extremely quickly and has a large amount of genetic variation among its population in those genes that code for non-life-sustaining functions (things like reproductive speed, genes for immune resistance, that sort of thing). That variation rises from the very lax nature of a virus' genetic error-checking system, so basically that DNA/RNA can mutate without being corrected. And as long as its only in those non-vital areas, the virus can exist.

Thus when you try to treat a virus with any drug, there almost certainly will be one or a few of them that can resist the drug in some way. The longer the drug is administered, the better those few will survive, since the environment will kill off all the other forms and leave the resources of the host for the taking. Depending upon the virus type, those few can become predominate in the body as fast as a few days, and the drug become ineffective. That's why we currently treat HIV by combining several different drugs into a "cocktail". Its the best way to kill off as many possible variants as we can. All in all this observation is called "natural selection" by most and "adaptation" by the rest. Its observable, quantifiable, and nobody debates it.

The second observation that led to the theory of evolution in science is the similarity that exists between living things. Again this is something that is easily seen for oneself. All creatures on earth capable of walking on 2 legs possess a tailbone, whether we have a tail or not. All vertebrates have spinal cords, digited appendages, stomaches, and similar patterned brains. During the early stages of development all vertebrates or invertebrates develop exactly the same and even look the same excluding size. Once species specific characteristics start to show development is still governed by similar genes, protein families, signaling functions. All life on earth uses the same genetic building blocks, similar building patterns, similar pathways for processing energy. Why? Why is everything so different, yet so similar?

The earlier scientists of last century were in the center of all of these observations, so it made perfect sense to them to connect the two areas. Someone successfully observed a process by which similar things became different thru inheritance. At the same time others were discovering fossils and similar geological formations all around the world. In this century, we've learned much about DNA and its structure, how much its allowed to change in an individual before it causes problems, how fast it can mutate and how it can be read many different ways to make different proteins. We've even observed how different environments can directly change how DNA is expressed in the body, so that you end up with small, large, fat, or thin individuals. So the theory of evolution as I see it used in science today is basically that given a certain period of time and different environments, genetic change can happen at a certain rate and be passed on to those generations that survive in each environment, causing originally similar things to become different.

This is the practical form of the theory that modern biologists operate under. That, however, is as far as I can go. The step further that given enough time and change in the environment, the world as it exists today could arise from basic chemical processes...I can't go there. I'm still learning about the discoveries that lead some to think that. But as far as the basic idea goes, I think Darwin and his colleagues were on to something. After all, if you think about the logistics of the story of Noah, his ark could not of held a male and female of every currently existing species on the planet, even if you only consider the land animals. Unless there was some serious divine intervention, its spatially impossible. Not to mention the fact that from a gene pool of 8 people every person on the earth arose, with all different skin types, heights, shapes and sizes. If from such a small gene pool such variety could arise even among us humans (and if you go by the biblical clock, in such few millenia), than I certainly think the practical form of evolution is possible, even significantly reasonable.

That's why I referred to the philosophy and the science of evolution before. Origin is actually a philosophical question, and while we can logically extrapolate back thru time using our math and what we know of our world, we can't observe, test, or confirm anything we say about it. The biggest flaw in intellegent design as a theory is that it isn't practical. While it rightly questions how such similar things can be so different, it doesn't address why such different things are so similar. As such its more idea then observation, and that doesn't help us go about the business of science (which is basically the business of describing, understanding, and subduing the world). Creationism is even more dangerous to throw in there. Once and for all, the story of creation is NOT a scientific theory. And it CANNOT be taught as one. Creation is accepted on the evidence of witnesses, not the evidence of physical interaction with a physical world. If you ask me, the physical evidence that God exists is that this world, this universe operates under a certain set of orderly conditions, apart from which it cannot exist as it is now. Just like evolution assumes, something cannot come out of nothing. Something can only come from something else. To an evolutionist, that something could be another universe that existed before this one. To a creationist, that something is God. But to prove that one way or the other is something that science can't do, and I don't think its meant to. "Proof", after all, isn't evidence, but the acceptance of some meaning attached to that evidence as truth.

That's what I think so far. I'm still learning, and there's a lot to read and study. If I come across something I think you guys will appreciate I'll recommend it, so you can read for yourselves. But this is a pretty good summary of what I've found so far.