Getting a Big Head about Evolution

Katrina Voss

During a brief stint blogging about weather, climate, and meteorology, I had occasion to use the phrase “bipedal primate” to refer to those particular hairless hominids who by definition should have the requisite cranial stuffing to make sense of those words. In response, an angry patron wrote me a brief email, “Keep the religion of evolution to your self [sic]!!! Just shut up and report the weather!!!!!”

I can only assume that the (probably first-time) reader of my blog considered one exclamation mark insufficient and thought the additional seven might clarify the depth of his fury. In addition, his stylistic choice to split the word yourself into two was probably meant to add an element of staccato. I should point out that my blog’s general theme was ruminations on biometeorology, or how weather and climate affect the human organism. (For a time, the series enjoyed the naughty title: “The Extra-Meteorological Affair.”) Only peripherally did I ever hint at my acceptance of evolutionary theory in particular or naturalism in general. What’s more, even if so inclined, how is one to tiptoe around all things offensive to creationists when writing about, well, science? Still, I do not pretend that when the opportunity arises there is no temptation to sneak in a little cheerleading for Darwin and have a bit of fun with what it provokes.

There’s nothing like a person who questions the state of his or her own evolution. Here was my irate reader, the ideal recipient of the familiar but timelessly clever reply, “Fine: I evolved; you didn’t.” And here I was: a geneticist’s sufficiently prickled wife, to whom it occurred to ask her husband, “Darling, might some people actually be less evolved than others?” in the hopes of gathering science-approved fodder for a tongue-in-cheek response.

If you have ever lapsed in judgment by clumsily planting the words less or more or—Blumenbach forbid!—better or worse in the vicinity of evolution, you know the exasperation you can inspire among dyed-in-the-wool scientists. You know no answer will come simply and without prelude. You know what a can of worms you have so inelegantly opened with a question about how “evolved” one individual—much less one species—is or isn’t: the complete mass of genomic sequence data fully supports Darwin’s idea of a single origin of life. Since evolution only has direction in time, in a very real sense all life today has evolved the same amount—four billion years. Phenotypic evolution is likewise dependent on the particular geography, climate, and other circumstances and has nothing to do with “quality” as we naked apes project it. Where comparisons are concerned, there is no absolute reference point for determining better or worse or zenith or nadir, only suited or unsuited (a pass/fail system, one might say) for survival and procreation.

So much for the makings of a tidy, biting retort I could bang out in an e-mail to my reader. I ought to know better. Although not as fun as publicly challenging yet another pharisaic creationist, the occasional jab at (one’s own) human smugness is no less critical. When it comes to evolution, both deniers and embracers get carelessly simplistic about what the word means in the first place. That is, when it comes to humanness, we humans get a bit too big for our britches—whether the britches (or genes) in question are God-given or evolved. For creationists and evolutionists alike, our species too often demands a sort of exclusivity and snobbishness. The former group, of course, declares a unique-to-us, super-special God-spark called a “soul.” The latter group showcases opposable-thumb-operated tools, art, phallic skyscrapers, and language like trophies earned after an evolutionary uphill climb. (The very word humanist implies claim to a throne upon which no other species may sit.)

We have big, impressive brains, but so what? Bonobos, who also have big brains, have bigger, more impressive testes and vulvas. How is superiority even measured in the first place? By the Encephalization Quotient (brain mass to body mass ratio)? Even this measure allows for some debate about our supremacy over tree shrews. By time? Our species is indeed quite young at 150,000 years old, having walked the earth a mere tenth the amount of time as Homo erectus—a fellow human species that met with extinction several thousand years ago. By number? Without question, that honor goes to our most prolific neighbors: insects, nematodes, worms, and bacteria. By moral superiority? Humans are more violent than all the other apes save perhaps chimpanzees. We atheists may have swapped “bipedal primate” for “made in God’s image,” but are we any more willing to relinquish our status as the ne plus ultra of life forms?

Human elitism and semantic imprecision aside, the answer to my original question, “Might some people actually be less evolved that others?” is, it turns out, a conditional “Yes.” Variant forms of genes (alleles) all had an origin as a single DNA molecule. Evolution at the genetic level is most fundamentally the process of change in allele frequencies. Through the generations, new forms—the derived alleles—emerge first by mutation and then can either increase or decrease in frequency. Thus, for any genetically determined trait, a particular person today might have a mix of alleles, some of a type more common in the past (ancestral alleles) and some of the derived type. One example is the persistence of lactase into adulthood. This derived allele originated only recently in regions of Africa and northern Europe, allowing hungry humans to benefit from an extra source of calories and nutrition—dairy products—throughout life. The ancestral state, shared with other mammals, is to cease production of lactase in the stomach and small intestine after being weaned. This is still largely the rule among the indigenous peoples of Asia, southern Europe, the Americas, and most of Africa. In that sense, perhaps, one can be more or less “evolved”—or more accurately, any chunk of one’s genome can be more or less recently changed.

Not quite the bumper-sticker-worthy rejoinder for which I had hoped. Sifting through the tedious details of science (however fascinating) has a way of plucking away the snappiness of memorable slogans. Thus, I did not send this answer on to my God-fearing reader along with contrite admissions of my co-guilt in matters of human exceptionalism. In the end, we were both left to pout about our relative insignificance in relation to our fellow Earth-dwellers. Still, one might say that tendency toward hubris and self-congratulation does in fact reveal something unique about our species. To quote my favorite geneticist (my husband), “Shakespearean tragedies could have been written about our fellow apes, just not by them.” Then again, there are moments when, as my reader suggested, we apes ought to just shut up and report the weather.

 

Katrina Voss

Katrina Voss works as a bilingual broadcast metrologist and holds the AMS Seal. She is collaborating with her husband, a Pennsylvania State University physical anthropologist, on a book about evolution, genetic ancestry, and society.


During a brief stint blogging about weather, climate, and meteorology, I had occasion to use the phrase “bipedal primate” to refer to those particular hairless hominids who by definition should have the requisite cranial stuffing to make sense of those words. In response, an angry patron wrote me a brief email, “Keep the religion of …

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