Regardless of how it works, evolution is for real

Robert M. Sapolsky
San Fancisco Chronicle
December 10, 2004
WELL, NOV. 2 confirmed that we are a vastly dichotomized country. This red-state/blue-state divide has various flashpoints: abortion, stem cells, same-sex marriage, the legality of a war based on lies -- all that stuff. But another flash point increasingly looms -- the teaching of evolution. A number of states and cities allow intelligent design, typically considered a code-phrase for creationism, to be taught alongside evolutionary biology. And, as an even more extreme event, last month a school board in rural Pennsylvania voted to require the teaching of intelligent design alongside evolution.

Sitting here safely in the bluest of cities, it strikes me that there are some key questions whose answers may help to counter this rising tide.

1. OK, evolution is about bones, or just-so stories about how the giraffe got its long neck, or about how our ancestors once were some brine shrimpy sorts of things. Has anyone actually shown evolution to occur as an ongoing process?

Plenty have. Evolution is the process by which the patterns of heritable, genetically influenced traits in a population change over time in response to changing environmental demands, and where the traits that are more adaptive in that environment are the ones becoming more prevalent. By that weighty definition, here are some examples of evolutionary change that have occurred in our lifetimes: the increasing prevalence of people who are genetically HIV- resistant in certain high-risk populations; changes in wing color in moths in England as soot-belching factories changed the color of tree trunks and thus of what color afforded camouflage; changes in the shape of beaks on Darwin's famed finches in the Galapagos Islands in response to shifts in food resources; changes in the prevalence of some Pacific Islanders with a certain physiology of food storage in response to the introduction of Westernized diets; adaptive changes in the prevalence of certain genes in populations of rats caught in American cities over the last century, or in populations of snakes. And, as a bit of evolution that may doom us all, the resistance of bacteria to the antibiotics we fling at them. Evolution is for real, in the present tense.

2. So what's with this "theory" of evolution business? How can scientists spend careers arguing with each other about evolution, if it's supposed to be a fact?

That's because scientists don't argue about whether evolution is for real; that's proven. They argue about how exactly it works. Contemporary evolutionary biology deals with such questions as: Do new species only evolve out of isolated populations? Or: Is evolutionary change mostly gradual, or can it occur in big, dramatic leaps? Or: Does natural selection mostly work at the level of the gene, the individual or the population? Scientists happily come close to blows at conferences over those questions. But the factuality of evolution is a given in all those debates. If I remotely understand what astrophysicists do, some spend time trying to figure out how radio waves can paradoxically escape the inescapable gravitational pull of black holes. But that doesn't mean that gravity is just a theory, and that physics teachers should be mandated to give equal time to Siegfried-and-Roy levitation tricks.

3. In the face of such science, who are the folks pushing for intelligent design?

Undeniably, some are scientists (although it is rare that their expertise is in the realm of evolutionary biology). Others are educated nonscientists. But the rank and file of intelligent design supporters is most likely to come from the parts of the country with the lowest literacy rates, the lowest percentages of high-school graduates and the lowest rates of government investments in education. Much has been made of the, er, Jed-Clampett profile of the typical intelligent-design supporter, but I'm not sure if the education factor is the most meaningful correlate of being opposed to evolution. I suspect that of greater significance, those parts of the country are also among the poorest, where jobs are most likely to be outsourced overseas, the farthest out in the sticks from the proverbial information highway, the most inequitable in income and the unhealthiest with the shortest life expectancies. These are people who, for many generations, have tended to get some of the worst deals amid our culture's mythologies that everyone is born equal and anyone can become president or maybe even Bill Gates.

This downtrodden status can cause some bizarre, twitchy forms of ire -- say, deciding that the liberal media is the enemy, rather than, say, our country's robber barons, whose interests they keep being convinced to vote for. Or to be skittish about technological and cultural innovations, not because these folks don't understand them, but because they understand all too well how the newest new is going to marginalize them even more in the boondocks of America.com. And to dislike evolution, because of a side branch of evolutionary thinking that has metastasized ever since Darwin, which has a sordid record of doing bad things to folks like these. This is Social Darwinism, the pseudoscience that evolution is about "should be" rather than "is," that folks on the lower rungs of society are peopled with individuals who are evolutionarily meant to be there, and that all is biologically just in this stratified world. Add in the potentially incorrect belief that accepting evolution is incompatible with one of the more common sources of solace in that corner of the country, namely fundamentalist religion, and you've got some unhappy campers.

Ultimately, I think that making sense of the anti-evolution movement requires understanding and empathy for the emotional core that fuels the rejection of 19th-century science, let alone 21st-century science. And despite that nice blue-ish sentiment, nevertheless, we should not give an inch in fighting to make sure our children are not taught nonsense.

Stanford neurology professor Robert M. Sapolsky is the author of "A Primate's Memoir," among other works.