Tales of a Feathered Tail

Natural History, Nov, 2000 by Stephen Jay Gould

Soon after birds branched off from dinosaurs and gained the power of flight, some may have branched off again as land-bound runners. Why do some people have a problem with that?

One fine day, or so the legend proclaims, Joseph Stalin received a telegram from his exiled archrival, Leon Trotsky. Overjoyed by the apparent content, Stalin rounded up the citizenry of Moscow for an impromptu rally in Red Square. He then addressed the crowd below: "I have received the following message of contrition from Comrade Trotsky, who has obviously been using his Mexican retreat for beneficial reflection: `Comrade Stalin: You are right! I was wrong! You are the leader of the Russian people!'"

But as waves of involuntary applause rolled through the square, a Jewish tailor in the front row--Trotsky's old school chum from yeshiva days--bravely mounted the platform, tapped Stalin on the shoulder, and took the microphone to address the crowd. "Excuse me, Comrade Stalin," he said. "The words, you got them right; but the meaning, I'm not so sure." Then the tailor read the telegram again, this time with the intended intonation of disgust and the rising inflection of inquiry: `"Comrade Stalin: You are right?? I was wrong?? You are the leader of the Russian people??'"

I have never been able to regard this joke with equanimity, because I can't help wondering what happened to the poor tailor, who probably suffered more than Trotsky, albeit anonymously. But I value the tale as a lesson about the importance of context. We may get every word right but, in a pungent military acronym (the superlative degree of SNAFU, I have been assured by army grammarians), still get the meaning FUBAR (defined by the dictionary, in genteel terms, as "fouled [euphemism] up beyond all recognition"). As I write this penultimate essay of 300 and look back upon a few successes in a sea of persisting ambivalence, I can only conclude that my central subject for "This View of Life"--evolution itself--must surpass all other disciplines in featuring straightforward facts enshrouded in difficult or ambiguous meanings.

The popular understanding of evolution includes at least two false assumptions, so widely shared and so deeply (if unconsciously) embedded in the context of conventional explanations that many plain facts, easily grasped at a superficial level of overt recitation, almost always enter the public discourse of newspapers, films, and magazines in a highly confused form that "science writers" either mistake for the actual opinions of scientists or, more cynically, choose to present as the literary equivalent of "easy listening" for succor in drive-time traffic jams.

In the picture conveyed by these two related fallacies, evolution becomes, first of all, the transformation of one kind of entity into another, body and soul. So fish evolve into amphibians in a "conquest" of the land, and apes leave the safety of trees, eventually to become human by facing the dangers of terra firma with a weapon in a liberated hand and a fresh twinkle of insight behind the eye. In the second component of this transformational view, descendants win victory from the heart of their valor in the face of natural selection--for "later" must mean "better," as the land yields to explorational metaphors of conquest or colonization while the African savannas, for the first time in planetary history, hear sounds of progress in the voice of real language.

But evolution proceeds by the branching of bushes, not by the morphing of one form into another, with the old disappearing into the triumph of the new. Novelties begin as little branches on old trees, not as butterflies of Michael Jordan refashioned from the caterpillar components of Joe Airball. Moreover, most novelties, at least at their origin, grow as tiny twigs of addition to persisting and vigorous bushes, not as higher realizations of ancestors that literally gave their all to a transcendence of their former grubby selves.

Amphibians and all their descendants have done well enough on land, but fins beat feet on the vertebrate bush, where the majority of twigs (species) sprout among fishes. I do not deny the transient success, and interesting novelties, of humans. But Homo sapiens occupies only one twig on a modest primate bush of some 200 species, and even our most distantly related subgroups, in both evolutionary and geographic terms (say, the San of southern Africa and the Sami of northern Finland), show very little genetic divergence, whereas two populations of the same species of chimpanzee, separated by only a few hundred miles of African real estate, have evolved many more genetic differences, one from the other. (This initially surprising fact makes evident sense once we recast our conceptions in properly bushy terms. All living humans descended from common ancestors who lived in Africa less than 200,000 years ago--despite our subsequent spread throughout the world. The two chimpanzee populations may have remained in geographical proximity, but they split from a common ancestor far longer ago, thus providing much more time for the evolution of genetic differences in the separated groups.)