Sexual selection theory suggests that much of the behavior and some of the appearance of an animal is adapted not to help it survive but to help it t… - Matt Ridley

It is hardly surprising to find that the males best at seduction tend to be the best at other things as well; it does not prove that females are seeking good genes for their offspring.

The conclusion that all these studies converge upon is that about half of your IQ was inherited, and less than a fifth was due to the environment you shared with your siblings – the family. The rest came from the womb, the school and outside influences such as peer groups. But even this is misleading. Not only does your IQ change with age, but so does its heritability. As you grow up and accumulate experiences, the influence of your genes increases. What? Surely, it falls off? No: the heritability of childhood IQ is about forty-five per cent, whereas in late adolescence it rises to seventy-five per cent. As you grow up, you gradually express your own innate intelligence and leave behind the influences stamped on you by others. You select the environments that suit your innate tendencies, rather than adjusting your innate tendencies to the environments you find yourself in. This proves two vital things: that genetic influences are not frozen at conception and that environmental influences are not inexorably cumulative. Heritability does not mean immutability.

Evolution is something that happens to organisms. It is a directionless process that sometimes make’s an animal’s descendants more complicated, sometimes simpler, and sometimes changes them not at all. We are so steeped in notions of progress and self-improvement that we find it strangely hard to accept this. But nobody has told the coelacanth, a fish that lives off Madagascar and looks exactly like its ancestors of 300 million years ago, that it has broken some law by not “evolving.”