June 23, 2005

debunking arguments against evolution

If you've been reading this blog for any length of time, you know that I am a biologist and that I get extremely irked when presented with retarded arguments either in favor of creation or against evolution. Creationists (and their thinly veiled counterparts who believe in 'intelligent design') fail to understand that what they are proposing is not science. If they could even begin to propose any sort of _testable_ hypothesis I would be amazed, but they can't. Anyway, I guess I should have known that they existed, but up until a couple of weeks ago I didn't know that there were other blogs that are devoted to debunking ID and other religious loons. (If you're interested, try Pharyngula, The Panda's Thumb, and The Loom to get started; these focus mostly on biology, as is my wont, but I've also noticed a few other blogs on physics and geology.) Over at The Loom, someone named Doug posted this into a comment thread:
Isn't it amazing how everything seems to provide evidence for evolution? The brain shrinks in some form of pygmy homo erectus. Thats evolution! Ancient genes survive millions of years unchanged. That's evolution?! Women have orgasms. That's evolution! Although not all women have orgasms and they still manage to reproduce hmm luckily with the right spin...That's evolution! We live in a civil society with people working for cooperative goals. That's evolution! Unfortunately some people murder and rape. Just an unfortunate side-effect, but that's evolution. Not only is everything evidence for evolution but evolution explains everything! No its not circular reasoning its Evolution! Thank goodness we don't need to resort to God to explain the world around. Now we have Evolution! Its the all-encompassing answer to the ultimate question (I always thought it was 42). The evolutionist has reached the omniscient nirvana. maybe we should start meeting at the biology lab on Sunday mornings. We can sing some Evolution Hymns. Do they exist? Don't worry they'll evolve. I'll just start selectively pressing some keys on the organ and type a few letters while blindfolded. Okay I'm getting a little carried away...chalk it up to evolution.
Zimmer responds in this post but Doug responds again in the comments. Here's an excerpt that goes to show that he has no idea what he's talking about:
The problem with Evolution is that it is never defined. Rather, it is defined (or its definition assumed) based on the context of the thought. One may make a statement like: We can see evolution in action when bacteria evolves resistence _[sic]_ to antibiotics. In the first instance of "evolution" its definition is assumed to be - common descent with modification, such that all organisms can be traced back to a common anscestor. The second instance, the word "evolves" refers to a population emerging based on "natural selection" favoring an attribute for survival. The assumption that underlies this equivocation is that given enough time the second will add up to the first. This is an erroneous assumption as selection can only choose from already existing choices and therefore has no power to explain the origin of the choices.
He makes the erroneous assumption that the existing choices, as it were, only have one function. Even in his own given example, it would be easy to imagine the existence of an enzyme necessary for regular metabolic function of the bacterium but that has very marginal activity for breaking down a toxin (in this case, antibiotics). Maybe it even has no activity at all. But factor in mutation, and all bets are off. If you start with marginal enzymatic activity, but apply selective pressure, in relatively no time at all you'll have an enzyme that is good at eliminating the antibiotic. Even if you have no enzymes at all present in the cell that have functional ability, a mutation might result in something that binds to the antibiotic, thereby retarding its action, and eventually, it may evolve into an enzyme that not only binds, but cleaves the antibiotic. Random mutation has more power than you might think. Hell, whole research groups have been formed to harness the power of directed molecular evolution to develop new and novel catalysts. PZ Myers has a great post up summarizing the path that yeast took in developing the alcohol dehydrogenase family of enzymes, which beautifully illustrates the concept of genes can have more functions that their primary ones.

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