[Update: reading this post, I can see that I was in a pretty testy mood when I wrote it last night. Intelligent Design does that to me. So if you're not in the mood to be ranted at, come on back tomorrow and I'll see what I can do for you. . .]
Further update: comments have now been turned off, to keep this one from rising from the grave. No doubt I'll post on ID again eventually, so everyone will have another opportunity to ventilate their opinions.
OK, one more on this topic, and then we'll try to give it a rest until the Dover school board decision comes down. (The comments to the yesterday's post are still rolling right along, though, as you'd expect from a debating ground like this one). The article by Jerry Coyne I linked to yesterday gives some good anatomical arguments against intelligent design. But I wanted to zoom down to the molecular level for a minute, since after all, I am a chemist.
DNA is a wonderful molecule, no doubt about it. And to someone like me, who believes that the evidence for evolution is overwhelming, it's also a fine illustration of how it works on a molecular level. Others, though, no doubt see in its intricacies the hand of a creator. What, I wonder, are we then to make of the degraded remnants of old viral DNA in our genome? Designed in there, or not? Or what about the long stretches that seem to do nothing but repeat the same few base-pair letters over and over - dozens, hundreds, or thousands of times? Doubtless the Designer would have his reasons, but perhaps some of these would have been better implemented with repeats that aren't so prone to breakage and mismatch. Hundreds of terrible diseases result. (That page is only the barest sample. It's an awful topic to research). It's almost as if these things persist as the residue of ancient random choices or something.
Moving on to what are supposed to be the normal genes, we find entire books can be written on the horrible consequences of tiny changes in the genetic code. Take the so-called Swedish and Dutch mutations in the amyloid precursor protein. Switch the DNA a bit, and you get a new amino acid in the protein. Get the wrong one, and you die, most terribly, from early and rampaging Alzheimer's disease with complications. Those particular mutations have been in families for hundreds of years now - we've tracked them through the generations. They're still with us because the people involved live long enough to have children - many of whom are destined to die the same terrible way - before the underlying disease finishes them off. It's almost as if the consequences of a mutation were more severe when it affects reproductive fitness.
Mysterious ways, mysterious ways. No doubt that accounts for why we (and guinea pigs, and Peruvian fruit bats) can't make our own vitamin C, the way the other mammals can. Or why our livers respond to the excess of free fatty acids in type II diabetes by. . .making more sugar, which is exactly what the body doesn't need. There must surely be a reason, too, a good well-designed one, for autoimmune diseases: having our bodies tear themselves to pieces on a cellular level; I can't wait to hear why that feature was built in. It's almost as if once we've had children, just about anything can happen to us.
I'll stop there. I could go on for pages. Suffice it to say that when I look at the biochemistry of living systems, I see an amazingly complex system, wonderful to behold. And it's held together with duct tape, chewing gum, and weathered pieces of wood - whatever was handy, and whatever worked. It's almost as if it's just been tinkering along for a billion years.