Wednesday, September 24, 2014

Evolution: Common Misconceptions, or "What Evolution Is Not"

I've recently been reading a book by Agustín Fuentes, Race, Monogamy, and Other Lies They Told You: Busting Myths about Human Nature with my girlfriend. We're only through part 1 (and the prelude of part 2), but it's an incredible read thus far, and I highly recommend it to anyone who is serious about their research in anthropology, evolution or human variation. Dr. Fuentes lays out a "toolkit," in his own words, on how to bust myths about human nature by applying the principles of genetics and culture to three common pervasive myths found in our society: (1) human race; (2) inherent human aggression; and, (3) sex.

Chapters 2 and 3 struck me well, but chapter 3 "Evolution Is Important -- but May Not Be What We Think," was especially informative and helpful. Dr. Fuentes starts off with a quote by popular science writer Nicholas Wade, who has recently come under fire for his book A Troublesome Inheritance: Genes, Race and Human History. The quote is from an article in the New York Times, and it says the following:
"Many have assumed that humans ceased to evolve in the distant past, perhaps when people first learned to protect themselves against cold, famine and other harsh agents of natural selection. But in the last few years, biologists peering into the human genome sequences now available from around the world have found increasing evidence of natural selection at work in the last few thousand years, leading many to assume that human evolution is still in progress."
The quote reflects on two popular misconceptions held by the public about evolution, which we will get to in a moment. It's important to note first, though, that this illustrates more than just misconceptions about evolution, but a lack of understanding in even the educated public, and the necessity of a false dichotomy. As Dr. Fuentes points out, "To sell the story, the false representation of a 'debate' as to whether evolution happens in humans has to be a central theme."

Of course, many people in the public hold the beliefs that Wade is referring to; however it simply isn't true that the primary debate amongst informed scholars is over whether or not evolution is happening in humans or, as some people often misinterpret, that evolution "stopped at the neck" in humans.

This objection refers to the debate over the Black/White IQ differential, specifically the position that most, if not all of the variation in IQ results between these two groups is a result of the environment. The problem with the characterization "evolution stopped at the neck," however, is that just because someone doesn't believe the differential is a result of evolutionary or genetic differences, that doesn't mean they don't believe human cognition has evolved. Evolution is complex, and even someone who suggests that the differential is a result of evolution doesn't necessarily mean it was a product of adaptation or natural selection. This is a gross oversimplification of how evolution works, and what the real debate entails, and thus we should now move into the five common misconceptions about evolution that are popularly held by the public.

1: Evolution is "survival of the fittest."

I can't tell you how many times I've heard this implication. To begin, Charles Darwin never used the phrase "survival of the fittest" -- this concept otherwise known as "social Darwinism" is attributable to Thomas Hobbes and Adam Smith. The concept is an interpretation of one aspect of evolution: natural selection. Natural selection is Darwin's process of "descent with modification," and states that some gene variants will help an organism reproduce more successfully, and that if these variants are heritable, they will become more common within a population over time. These variants are then seen as adaptations to a specific environmental context.

What this means is that "the fittest" doesn't necessarily mean the biggest, baddest or strongest. It's specific to an environment, where "the fittest" may be the exact opposite. Consider an easy example: the field mouse. It is not the fastest creature in the world, it is not the strongest, it does not have a serious bite, and it poses pretty much no risk to any creature of any size bigger than itself. So why does it continue to succeed and reproduce? Because "bigger" does not mean "better." Speaking of better, this brings us to the second misconception about evolution.

2: Evolution results in perfection.

As Fuentes notes, evolution is not oriented towards progress, nor does it result in organisms fitting perfectly with their environment. To quote, "The corollary to this is that if something works well we perceive it as having 'evolved' for this particular purpose."

Evolution is not perfect -- it's sloppy, and isn't geared towards making something ultimately "better." When an organism has traits which allow it to successfully reproduce in its environment, and these traits are a result of evolution, it does not mean that it evolved that way for a purpose.

3: Evolution happens by chance.

There is only one aspect of evolution that represents "chance," and that would be genetic drift. Genetic drift suggests that random events can sometimes alter the allelic frequencies of a population. Fuentes offers an example of this: take hair color. There is a small population living on an island with hair color gene A, and there are three alleles of the gene: A1, A2 and A3. Say the population is made up of 80% A1, 10% A2 and 10% A3. Now, imagine that most of the population lives on the north coast of the island, and that part of the island is hit by a major tsunami. Now, the only people remaining are the smaller numbers of people on the south end of the island, changing the allelic frequency to maybe 33% for all alleles of the hair color gene A. This results in evolutionary change, but not because of anything having to do with the genes or the alleles themselves, but with a random event which drastically changed the makeup of the organisms in the population. Genetic drift, then, is most potent in smaller populations, because random events are less likely to have significant effects on larger populations.

But as said, this is the only aspect of evolution that relies on randomness or chance. There are three other major components of evolution: gene flow, natural selection and mutation. We've already explained natural selection. Mutation is the means by which organisms gain new genetic material, where it creates a new sequence in a gene that produces a protein or regulation that functions better than previously. Gene flow is the movement of alleles within and between populations as a result of migration. The allelic frequencies within and between two populations can change if the populations are close enough together that allows for migrations between them. The allelic frequencies between the two populations can either become more similar if there's enough gene flow or, if gene flow is restricted, they can remain the same. Gene flow, natural selection, and mutation, then, do not occur by chance, but have multiple reasons for occurring.

4: If something has evolved in a certain way, that is how it should be.

This one is a bit complicated, but it's similar to misconception #2. Basically the idea is that if an organism exhibits a certain trait, and that trait is a result of evolutionary change, then the exhibition of that trait is the way things are supposed to be. This is not necessarily true, because there are many things that have occurred via evolutionary means, but were intended for a different purpose than what they're used for today. This is called exaptation.

One beautiful example of this is bird feathers. Originally, bird feathers evolved as a structure of temperature regulation. The feathers on a bird's wings allowed it to trap air underneath, allowing it to either cool off by lifting its wings up, or warm up by bringing its wings in. At some point, the wings on some birds became substantial enough that they were able to glide, and this unintended function resulted in reproductive success. Now, wings are used for flying. This is a perfect example of something that occurred through evolutionary processes, but did not serve the function it does now, thus showing that even if something has evolved does not mean it was intended to be what it is today.

5: Evolution can stop, has an end, or has a goal.

This is our last misconception. Evolution does not stop; it is always ongoing. Evolution is also not goal-oriented -- it doesn't have a goal, and it doesn't seek perfection. Something that has occurred by evolutionary means is not the finish line, and it is not more "natural" than other things. Traits that have evolved are the result of any number of processes that can and will continue to act on us and every other organism over the course of time.

These misconceptions overlap in many ways, but are very applicable to modern times. It's commonly held that if something has evolved, or if something is engrained in our biology, then that is "correct" or "natural." This is the basic premise of human nature which Dr. Fuentes argues against. Just because something is biological or evolutionary does not mean it is any more natural than any other aspect of our lives. The premise of this idea is that, for example, between our biology and our society, biology takes precedence as we cannot avoid its grasp, and our society or social situation can change. This simply isn't the case, though: our biology is constantly changing, and the strength of our genes is not more powerful than the strength of our environment.

Creationists, determinists, indeterminists, racialists, and many other groups of people will commonly fall into the belief in one of these misconceptions as part of their arguments. Be equipped and well-informed of what evolution is and is not so that these misconceptions can be further dispensed, and the core of the arguments can be reached instead of the nuances of what evolution does or does not imply.

And above all, thank you very much for reading.

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  1. An Anonymous commenter tried to link to a list of book reviews of Wade's book, effectively missing not only the point of this post (by thinking A Troublesome Inheritance was anything more than a segue into the primary topic), but not being able to take anything from the post and apply it to Wade's speculations.

    In effect, I consider this spam; but in reality, I just know that it's somebody trying to shoehorn their content into anything that mentions Wade's name.

  2. Sorry I hadn't gotten to this earlier, but I now that I have, I really took a lot from this post. It's informative, precise, and easy to understand. It's kind of amazing how many misconceptions there are about evolution that gets tossed around into public knowledge. I know growing up, many of the things you mentioned were things I were taught or thought I understood about evolution and how it works. Goes to show how easily information can be misconstrued and misinterpreted to the point that the majority of people think of these points as true.

    So, thank you once again for such important and an enlightening post!

    1. Thank you Mykala, but you don't need to treat this for more than it's worth. You read the book too. :P


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