Tom Gold, a scientist at Cornell University, believes that bacteria are living under our feet in staggering quantities–not in our shoes, although they are certainly there too, but deep in the crust of the earth. They are known to thrive in acid, on hot coals, and in deep-sea vents at 480 degrees Fahrenheit, so he figures that wherever water can seep into microscopic cracks in the rock, there you will find some hardy bacterium making do with just a few chemicals and the heat emanating from the center of the earth. There must be so many of these creatures, the professor has reckoned, that if we dug them up and spread them out they’d form a mat five feet thick covering every square inch of land on the planet.
The image is gratifying, but Gould reports that it’s as false as the creation stories that, in some minds, it has come to replace. In reality there is no vanguard, and no parade either; it’s more like a mob of endlessly variable forms, varying endlessly. They leave descendants, they stagnate, and eventually they go extinct (except those damn bacteria!), all with complete disregard for what might seem “better” to the vanity of the future. It’s true that as species filled up the available places a few organisms became more efficient or complex or intelligent or whatever other vague and self-serving adjective we may choose, but that’s only because life began, as it had to, at the simplest level. (“You cannot begin by precipitating a lion out of the primeval soup.”) Any subsequent change, though perfectly random, had nowhere to go but up; or more exactly, nowhere but away from simplicity. And that’s all, according to Gould, that can be said for so-called progress.
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This low view of natural selection is nothing new for Gould. In the 1970s he first made a name for himself in paleontology as cooriginator of the theory of punctuated equilibrium, which says that species don’t really change much except during isolated instants when new forms branch off abruptly. (The theory was also known, for reasons having nothing to do with the boldness of the theorists, as “evolution by jerks.”) Biology is irresistible as an arena for scoring political points by analogy, so Gould’s punctuations were seized upon, for better or worse, as proof of a more radical view of evolution; but in fact the instant of change is geological, big enough for both insurgents anxious to man the barricades and traditionalists content to work within the Darwinian system. What is more telling about the theory are the long governing periods of stability: during all this time, many millions of years, natural selection is relegated to pushing its humble broom.
Diversity isn’t just a remarkable feature of life to Gould, it’s the only standard he allows for evolutionary success. The genus Homo is a lonely twig, but “when groups are truly successful…their tree contains numerous branches, all prospering at once.” This is not only a lot friendlier than the old nature red in tooth and claw, it makes rodents the most successful of all mammals. Among animals as a whole, Gould is delighted to report, insects rule. And if you want to look at the big picture, you’re back staring at all those bacteria. I’m not sure what Gould proves by totting up the numbers of different species to declare his winners, but he has few doubts himself. It is “absurd,” he says, a “ludicrous case of the tail wagging the dog,” to see progress in evolution just because a few creatures have lifted themselves up and become more complex and intelligent than the mass of germs, bugs, and rats.
This is why Darwin believed that the mammals of Europe and North America were superior to those of Australia. He saw the marsupials’ coarser division of labor as the mark of “an early and incomplete stage of development.” Obviously a match between these two groups must remain imaginary, much like the contests fought routinely in bars between, say, the 1996 Yankees and those of 1927. But I think I can guess where Gould would come down on that one, and for reasons not very different from Darwin’s.
