I'm so very glad that The Loom
is back in Frequent Posting Mode. One of the things that I miss about graduate school is the constant barrage of new and exciting ideas, developments, experiments, and conclusions that happen in the science world. I had to teach myself Science as almost a foreign language and I miss translating in and out of it. This is why I like The Loom, The ESRC, and I depend on my still-in-grad-school friends for tidbits of amazing science.
I'm going to make a rather shocking confession at this point. Are you sitting down with a cold washcloth at the ready? Here it is: I THINK CREATIONISTS AND "INTELLIGENT" DESIGN PROPONENTS ARE DUMB!!! Yes, this must come as a complete surprise to everyone who's ever met me. I'll give you a moment.
Last night I slipped into Spiffy Science Fangirl mode when I read the article talking about an honest-to-Darwin transitional form from fish to tetrapod in the fossil record. I read that with great glee and had a few happy contemplations of the backpedaling and rhetorical nonsense that was about to be printed to "explain" how these new findings are propaganda or something else easily ignorable.This article is even cooler.
Now, I'm not just saying that because I'm more familiar with the techniques that are used in molecular genetics. Nor am I saying it because the article is written a bit more technically and it pinged all my Science Nerd receptors. No, I think that the concept of tracing a molecular receptor back through the evolutionary history, recreating the ancestral form, and then attempting to figure out the precise chain of random events that have led to what we see today is all sorts of nifty and something that I would love to work on someday.
Yes, it seems like a sketchy sort of scenario. "If this happened in just this way
and then this other thing happened, why, then you could see this other thing and by random chance that's what we've ended up with today! See how simple it is?!" But, really, it's something that you don't actually have to take with that much faith. Yes, we're allowed to have both faith and knowledge of science. No, I'm not going to explode for saying "faith" and "science" in the same sentence and speaking positively of both. Just let it go.
The thing about random chance driving evolution is that we can't so much hit the Rewind button and see how it would play out. This is one of the things that ID folks have latched onto with an iron grip. They claim that everything happened so that
humans would be created. No. Not true. We want it to be true, but it's not. But I'm seriously digressing.
The point I wanted to make about random chance and this article in particular is that the mutations mentioned in the lock-and-key mechanism started out as random, but are now standard. That's the driving force behind evolution. In many cases, the mutation will result in the death of the organism carrying it. Or that critter won't breed. Or they get buried and become part of the Burgess Shale. Or something. But when you look at a single protein, it becomes much simpler (and by "simple" I mean "requires years of work and lots of computer processing of statistics and more work") to understand how the process of random mutation can drive change.
Proteins are chains of amino acids. Amino acids are encoded by three DNA bases. If you change a single DNA base, the odds are good that you'll change the amino acid at that point. Sometimes, nothing happens - this is called a silent mutation. You have MANY silent mutations in your cells right now. I guarantee it. Sometimes something small gets changed that has a small effect on the protein's function, but it doesn't actively harm or help the organism as a whole.
Sometimes, though, a single base change in the DNA will completely change the activity of the protein. The wrong thing in the wrong place can have HUGE impacts on the function of the protein. Take sickle-cell anemia as an example. A single DNA base is changed. Suddenly, the red blood cells go from looking like jelly donuts to long, thin, flat plates that won't go through capillaries. A single point mutation, something that's utterly random, has sweeping effects.
Or you might have a mutation in the gene that controls alcohol metabolism. A single mutation there will either make it so that you get drunk exceptionally quickly or that your liver processes alcohol about 15 times faster than normal. If you mutate a single amino acid in the enzyme, you can force it to work faster or slower. Again, this is something that will happen randomly in a very small point and have huge effects.
And that's the point of evolution. A single individual will NEVER evolve. That's not how it works. It's a long series of little things that happen in the species as a whole over time. Some of these things are "bad", some are very "good". But just like the researchers in Oregon, we can take the baby steps back and piece together the clues that are still present in our proteins, bones, and physiologies. It's something that we CAN figure out. And that, to me, is the neatest thing of all.
*gets off soapbox*