Heroes: Part II

Sexual reproduction is a curious evolutionary adaptation. It reshuffles the genes of the current generation, guaranteeing that the next generation is similar to, but distinct from, its parents. Why do this? If a particular set of genes has been successful, why not reuse them as they are, rather than risking passing on a worse combination?

The answer is flexibility. The environment (and, indeed, the competitive environment) is not static, so a static genetic mix will not serve for long. The ideal system is one that passes nearly all of the most successful traits to the next generation, with a very small percentage of novelty thrown in. The novel genes are an insurance policy against change.

Societies use this strategy as well.

Conventionalists are society's standard gene load out - the tried and the true. Even Romantic Conventionalists, who oppose the prevailing the culture, are part of the standard genetic material. Because they pull directly against the tide of the society they prevent accelerating groupthink. They anchor the society against drift.

Fundamentalists are the novel genetic material. Their commitment to their ideas, rather than to society itself, means that they are forever moving in a completely independent direction. Sometimes they can be a cancer, like the thinkers who produced eugenics. Sometimes they can provide the adaptation that takes the society in a new evolutionary direction, as did the men who dreamed of a purer democracy, without royalty. Most often they are interesting, but harmless, with no strong effect on anyone but themselves (let me again refer you to Eric Falkenstein's brilliant post on how unusual ideas are one of the penalties of being intelligent).

Does Natural Selection Account for All Biophenomena?

No. But too many people who like to dabble in evolutionary explanations assume that it does.

The book, How Women Got Their Curves and Other Just So Stories is a good example of this. Many hypotheses are put forward for this or that characteristic or behavior, all explained in terms of selective pressure acting upon our forbears. We are as we are precisely because our clever genes have tried out various reproductive strategies, and the cleverest genes have won out.

What the authors fail to consider is the missing evidence.

Hair color can illustrate what I mean. Has hair color been strongly selected for? Are brunettes more common than redheads because brunettes possess an evolutionary advantage? Probably not. After all, there are many different common shades and hues, and no obvious advantage of one color over another presents itself. One might point out that light-colored hair is correlated with light-colored skin, which does possess an evolutionary advantage for people in northern lands. But one needs only to travel to the Caucasus to find that light-skinned people can have dark-colored hair.

So, maybe hair color has not been strongly selected for. Perhaps it is merely the result of chance, isolated populations, and group identity that Swedes tend to be blonde while Han Chinese are nearly uniformly dark-haired. Indeed, a fundamental mechanism at work within evolution is chance mutation. Only after a feature has appeared, as the result of a genetic accident, can the feature become the subject of selective pressure.

Imagine, for a moment, a world in which a Great Calamity early in human history has by chance killed off the ancestors of all modern humans except for a small group who were to become the forbears the Chinese. In such a world, nearly everyone would have dark hair since we all would have descended from the dark-haired survivors. Scientists studying evolution in that world would perhaps, upon considering themselves and their fellows, conclude that it must be the case that there had been some strong advantage to their ancestors in having dark hair, since human chemistry could permit other hair colors but no living humans were in fact so colored. The missing evidence that could have revealed the truth, died with the proto-Europeans in the Great Calamity.

Such scenarios have in fact happened repeatedly throughout the history of life. Why are the creatures that have built universities, governments, and shopping malls descended from the ancestors of marmots instead of from the ancestors of falcons? Because of a chance extinction and climate change that gave mammals an opening against dinosaurs.

Indeed, assuming that a trait has been selected for merely because it exists, or even because it is common or exclusive, is bad science. Science demands evidence to connect premises with conclusions (reasoning alone is not sufficient). Evolution is powerful science, and may be invoked in the work of others who are seeking to describe the world, but there is more to Evolution than selective pressure.