Bird taxonomy is a difficult field because of the severe anatomical constraints imposed by flight. There are only so many ways to design a bird capable, say, of catching insects in mid-air, with the result that birds of similar habitats tend to have very similar anatomies, whatever their ancestry. For example, American vultures look and behave much like Old World vultures, but biologists have come to realize that the former are related to storks, the latter to hawks, and that their resemblances result from their common lifestyle.

Besides justifying the transfer of wealth to kleptocrats, institutionalized religion brings two other important benefits to centralized societies. First, shared ideology or religion helps solve the problem of how unrelated individuals are to live together without killing each other—by providing them with a bond not based on kinship. Second, it gives people a motive, other than genetic self-interest, for sacrificing their lives on behalf of others.

The southward advance of native African farmers with Central African crops halted in Natal, beyond which Central African crops couldn't grow - with enormous consequences for the recent history of South Africa.

Our biggest threat is not an asteroid about to crash into us, something we can do nothing about. Instead, all the major threats facing us today are problems entirely of our own making. And since we made the problems, we can also solve the problems.

In short, Europe’s colonization of Africa had nothing to do with differences between European and African peoples themselves, as white racists assume. Rather, it was due to accidents of geography and biogeography—in particular, to the continents’ different areas, axes, and suites of wild plant and animal species. That is, the different historical trajectories of Africa and Europe stem ultimately from differences in real estate.

Ahead of me lies the familiar litany: weakening of the heart, hardening of the arteries, increasing brittleness of bones, decreases in kidney filtration rates, lower resistance of the immune system, and loss of memory. The list could be extended almost indefinitely. Evolution seems indeed to have arranged things so that all our systems deteriorate, and that we invest in repair only as much as we are worth.

We know from our recent history that English did not come to replace U.S. Indian languages merely because English sounded musical to Indians' ears. Instead, the replacement entailed English-speaking immigrants' killing most Indians by war, murder, and introduced diseases, and the surviving Indians' being pressured into adopting English, the new majority language.