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at doing two things at once than males and females are at each doing his or her own thing. Therefore, ancestral hermaphroditic animals were outcompeted by ancestral sexed animals: But why only two sexes? Because that was the only way to settle a long-running genetic dispute between sets of genes: What? I 'll explain later. But why does she need him? Why don ' t her genes just go ahead and make babies without waiting for his input? That is the most fundamental why question of all, and the one with which the next chapter begins:
In physics, there is no great difference between a why question and a how question. How does the earth go around the sun?
By gravitational attraction. Why does the earth go around the sun?
Because of gravity. Evolution, however, causes biology to be a very different game because it includes contingent history. As anthropologist Lionel Tiger has put it, "We are perforce in some sense constrained, goaded, or at least affected by the accumulated impact of selective decisions made over thousands of generations.' Gravity is gravity however history deals its dice. A peacock is a showy peacock because at some point in history ancestral peahens stopped picking their mates according to mundane utilitarian criteria and instead began to follow a fashion for preferring elaborate display.
Every living creature is a product of its past. When a neo-Darwinian asks, "Why? " he is really asking, "How did this come about? "
He is a historian.
OF CONFLICT AND COOPERATION
One of the peculiar features of history is that time always erodes advantage: Every invention sooner or later leads to a counterinven-tion. Every success contains the seeds of its own overthrow. Every hegemony comes to an end. Evolutionary history is no different.
Progress and success are always relative: When the land was unoc-cupied by animals, the first amphibian to emerge from the sea could get away with being slow, lumbering, and fishlike, for it had no enemies and no competitors. But if a fish were to take to the
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The Red Queen
land today, it would be gobbled up by a passing fox as surely as a Mongol horde would be wiped out by machine guns. In history and in evolution, progress is always a futile, Sisyphean struggle to stay in the same relative place by getting ever better at things: Cars move through the congested streets of London no faster than horse-drawn carriages did a century ago. Computers have no effect on productivity because people learn to complicate and repeat tasks that have been made easier:"
This concept, that all progress is relative, has come to be known in biology by the name of the Red Queen, after a chess piece that Alice meets in Through the Looking-Glass, who perpetually runs without getting very far because the landscape moves with her: It is an increasingly influential idea in evolutionary theory, and one that will recur throughout the book. The faster you run, the more the world moves with you and the less you make progress. Life is a chess tournament in which if you win a game, you start the next game with the handicap of a missing pawn.
The Red Queen is not present at all evolutionary events.
Take the example of a polar bear, which is equipped with a thick coat of white fur: The coat is thick because ancestral polar bears better survived to breed if they did not feel the cold: There was a relatively simple evolutionary progression: thicker and thicker fur, warmer and warmer bears. The cold did not get worse just because the bear 's insulation got thicker: But the polar bear 's fur is white for a different reason: camouflage. White bears can creep up on seals much more easily than brown bears can: Presumably, once upon a time, it was easy to creep up on Arctic seals because they feared no enemies on the ice, just as present-day Antarctic seals are entirely fearless on the ice. In those days, proto—polar bears had an easy time catching seals. But soon nervous, timid seals tended to live longer than trusting ones, so gradually seals grew more and more wary: Life grew harder for bears. They had to creep up on the seals stealthily, but the seals could easily see them coming—until one day (it may not have been so sudden, but the principle is the same) by chance mutation a bear had cubs that were white instead of brown. They thrived and multiplied because the seals did not see HUMAN NATURE
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them coming. The seal 's evolutionary effort was for nothing; they were back where they started. The Red Queen was at work: In the world of the Red Queen, any evolutionary progress will be relative as long as your foe is animate and depends heavily on you or suffers heavily if you thrive, like the seals and the bears.
Thus the Red Queen will be especially hard at work among predators and their prey, parasites and their hosts, and males and females of the same species. Every creature on earth is in a Red Queen chess tournament with its parasites (or hosts), its predators (or prey), and, above all, with its mate.
Just as parasites depend on their hosts and yet make them suffer, and just as animals exploit their mates and yet need them, so the Red Queen never appears without another theme being sounded: the theme of intermingled cooperation and conflict. The relationship between a mother and her child is fairly straightforward: Both are seeking roughly the same goal—the welfare of themselves and each other. The relationship between a man and his wife 's lover or between a woman and her rival for a promotion is also fairly straightforward: Both want the worst for each other. One relationship is all about cooperation, the other all about conflict. But what is the relationship between a woman and her husband? It is cooperation in the sense that both want the best for the other: But why?
In order to exploit each other. A man uses his wife to produce children for him. A woman uses her husband to make and help rear her children. Marriage teeters on the line between a cooperative venture and a form of mutual exploitation—ask any divorce lawyer. Successful marriages so submerge the costs under mutual benefits that the cooperation can predominate; unsuccessful ones do not: This is one of the great recurring themes of human history, the balance between cooperation and conflict. It is the obsession of governments and families, of lovers and rivals. It is the key to economics. It is, as we shall see, one of the oldest themes in the history of life, for it is repeated right down to the level of the gene itself. And the principal cause of it is sex. Sex, like marriage, is a cooperative venture between two rival sets of genes. Your body is the scene of this uneasy coexistence.
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The Red Queen
TO CHOOSE
One of Charles Darwin 's more obscure ideas was that animals '
mates can act like horse breeders, consistently selecting certain types and so changing the race: This theory, known as sexual selection, was ignored for many years after Darwin 's death and has only recently come back into vogue: Its principal insight is that the goal of an animal is not just to survive but to breed. Indeed, where breeding and survival come into conflict, it is breeding that takes precedence; for example, salmon starve to death while breeding.
And breeding, in sexual species, consists of finding an appropriate partner and persuading it to part with a package of genes. This goal is so central to life that it has influenced the design not only of the body but of the psyche. Simply put, anything that increases reproductive success will spread at the expense of anything that does not—even if it threatens survival.
Sexual selection produces the appearance of purposeful
" design " as surely as natural selection does( Just as a stag is designed by sexual selection for battle with sexual rivals and a peacock is designed for seduction, so a man 's psychology is designed to do things that put his survival at risk but increase his chances of acquiring or retaining one or more high-quality mates: Testosterone itself, the very elixir of masculinity, increases susceptibility to infectious disease. The more competitive nature of men is a consequence of sexual selection: Men have evolved to live dangerously because success in competition or battle used to lead to more or better sexual conquests and more surviving children. Women who live dangerously merely put at risk those children they already have.