Part 4 in a series. Click here for part 3: why transitional fossils exist.
There are some mysteries I will never understand, such as why Pikachus can’t exist in real life or how anybody could like cilantro (Trust me. It’s horrible). One such conundrum is the vehement denial of evolution that has dogged science for centuries. According to Bill Nye, this organized opposition appears only in the United States, where far-right religious groups hold political sway in the South and Midwest. I hope he is correct, though I can’t know for sure. In my time abroad I have encountered extremists of different kinds but none of this kind. Then again, these are not the types of people I tend to associate with. Before I digress further, let’s take a look at another of our misconceptions.
Why natural selection is not random
Even after a crash course in evolution (video below), many people still mistake natural selection for a process of chance. This misconception spreads through demagogues or sworn opponents of Darwin’s theory. The questions go like this: “Doesn’t it seem lucky that our feet evolved to walk so well or that our eyes are so good at seeing? Surely, no random process could build such finely tuned machinery, so evolution must be false.”
And they are correct: no random process would give such results. The gap in their understanding, of course, is that natural selection is by no means a random process. As discussed in a previous Misconceptions about Evolution, natural selection is quite the opposite. Individuals well suited to their environment survive to reproduce, passing their genes to their offspring. Over millions of years, organisms with more advantageous traits will survive and mate more frequently than those with poorly suited traits, leading to changes in the gene pool. The advantageous genes will appear more often, while the less helpful ones will become rare or disappear entirely. This is how natural selection works.
Let’s use the example of the eye. From a biological perspective, the eye is a wonderful organ, beautifully tuned to perceive the outside world. As our mistaken friends point out, the eye could not have appeared by chance, but must instead be the result of a meticulous process—such as evolution. Though the eye may appear to be “specially made” for our use, it is actually a freeze-frame in a multimillion-year process. Our ancestors probably did not all have such wonderful vision. In fact, many individuals probably couldn’t see worth a damn. Over time, those who could see their surroundings clearly outlasted those who could not (by avoiding hungry tigers, poisonous fruit, angry neighbors/inlaws, etc.). Throw in a few advantageous mutations and a pinch of genetic drift and we have an eye appropriate for human needs.
Note that not all evolution is devoid of chance. As a matter of fact, genetic drift is an exciting, purely statistical phenomenon that accounts for large parts of species’ growth. Evolution as a whole, however, is not a slot machine of genes. Natural selection may be slow, continuous, and in a ninth grade biology class quite boring, but in the words of Richard Dawkins, “Natural selection is anything but random.”
So now we know a little more about natural selection. Is this enlightening or is it old news? Better yet, have you ever heard someone claiming otherwise? Share thoughts and stories below, yo. As always, please like, share, or reblog this post if you enjoy it. That small click really helps me out! Be sure to check me out on Twitter and Facebook as well. Thanks for reading! Don’t forget to subscribe for new content every Wednesday! IT’S FREE!
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Comment question of the week
Is this enlightening or is this old news? Have you ever heard someone claiming evolution and natural selection are totally random? Crazy stories encouraged.