A common misconception is that evolution naturally selects for biological complexity, eventually creating advanced organisms like us. That couldn't be further from the truth

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FEW scientific concepts are as misunderstood as evolution. That isn’t just because of cultural resistance from religious fundamentalists. It has acquired all sorts of pseudoscientific baggage too, like the belief that it is about climbing a ladder of ever-increasing biological sophistication.

Evolution can be that, but the reality is usually much less grandiose. “Evolution is changed gene frequencies in populations,” says evolutionary biologist Richard Dawkins. That is it. If, for some reason, a given gene in a patch of weeds, say, gets slightly more or less common from one generation to the next, evolution has happened.

The gene doesn’t have to confer a survival advantage, or be “adaptive” or make the weed “fitter”. It doesn’t have to be “selected for” or increase biological complexity. It simply has to change in frequency, maybe by chance. That is all.

After many generations, says Dawkins, we may notice this as a change in an organism’s phenotype: its observable characteristics and traits. But changes in gene frequency happen all the time, often randomly, with the appearance of a new mutation or the chance death of an individual. Under certain circumstances, a certain set of genes expressed in a certain environment can give that organism a slightly better-than-average chance of survival and reproduction.

These genes are more likely to be passed on. Gene frequency has changed, and evolution has happened. But something else has taken place too: adaptation through natural selection. This special case of evolution renders a population fitter – as in a better fit, not physically fitter – for its environment.

No goal, no direction

This doesn’t imply progress …