It is the plain truth that we are cousins of chimpanzees, somewhat more distant cousins of monkeys, more distant cousins still of aardvarks and manatees, yet more distant cousins of bananas and turnips…continue the list as long as desired.
This “plain truth,” the shopworn image of apes as our “cousins,” expressed by Richard Dawkins in The Greatest Show on Earth, is one of the stock inanities of popular writing about science. Yet there isn’t one individual among our cousins the chimps who can read Dawkins’s words or understand them if they are read to him. Neither has there ever been nor will there ever be.
Biologic Institute molecular geneticist Ann Gauger opens the new Discovery Institute Press book Science and Human Origins with a chapter that is the most concise and lucid explanation I’ve come across stating plainly why Dawkins’s “truth” is little better than cheap sophistry.
It’s one of those clich�s that gets repeated so often that many otherwise thoughtful people are lulled into assuming there’s nothing further to think about on the subject. Of course a human being is separated from a chimp by a mere 2 percent of our DNA, so that’s that! Easy!
Not so easy, actually. Not at all. The professional representatives of Big Science say one thing when speaking to the public, and other things when speaking among themselves. The idea of an obvious cousinship between man and ape is premised on a smooth evolutionary transition from a chimp-like ancestor such as Australopithecus afarensis to a human-like ancestor such as Homo erectus.
But writing in Molecular Biology and Evolution as recently as 2000, University of Wisconsin paleoanthropologist John Hawks was candid in expressing the radical suddenness of this transition:
Our interpretation is that the changes are sudden and interrelated and reflect a bottleneck that was created because of the isolation of a small group from a parent australopithecine species. In this small population, a combination of drift and selection resulted in a radical transformation of allele frequencies, fundamentally shifting the adaptive complex; in other words, a genetic revolution.
The image I think of when I read those words — sudden transformation, radical shift, revolution — is the wolf man’s transformation, enacted so many times in Hollywood movies. But whereas in movies the iconic scene always has the man turning into a beast, here it’s the other way around.
How did it happen? Can we trace the path so that this revolution, unguided by any external source of intelligent agency and fueled by random genetic mutations winnowed by natural selection, had all the needed time and probabilistic resources to accomplish the transition? Gauger argues: Not anywhere near close to it.
She and co-author Doug Axe tested in the lab an easier case of evolutionary transition, from one similar but functionally distinct bacterial protein to another — “evolutionary cousins” of a humbler type. This very minor revolution would require seven coordinated mutations if not more, which in a population of bacteria would need something like 1027 years.
To put that in some perspective, remember that the universe is only about 1010 years old. It can’t have happened.
The problem of accomplishing the revolution that transforms a chimp-like ancestor into a member of the genus Homo is, of course, worlds and worlds and worlds more difficult. Dr. Gauger cites Dennis Bramble and Daniel Lieberman, writing in Nature and describing the immensity of difference in anatomical features — the unique gifts that make their first appearance in Homo erectus and Homo sapiens.
Remember we’re not talking about what are arguably called spiritual endowments — the ability to speak, write, do math, do art, appreciate lofty moral and aesthetic ideals, and the rest that science can’t even describe much less account for in evolutionary terms. We’re just talking about the anatomy.
Bramble and Lieberman count 16 such revolutionary changes and Gauger points out that the transition from our last presumed common ancestor with chimps is allotted only six million years by the standard timetable. This itself produces a defeater for any Darwinian narrative of human evolution:
Each of these new features probably required multiple mutations. Getting a feature that requires six neutral mutations is the limit of what bacteria can produce. For primates (e.g., monkeys, apes and humans) the limit is much more severe. Because of much smaller effective population sizes (an estimated ten thousand for humans instead of a billion for bacteria) and long generation times (fifteen to twenty years per generation for humans vs. a thousand generations per year for bacteria), it would take a very long time for even a single beneficial mutation to appear and become fixed in a human population.
Our uniquely human attributes constitute a quantum leap, not just an innovation, a leap that cannot have arisen without guidance. We are not souped-up apes.
In a neat irony, the Daniel Lieberman whose work plays a role in Gauger’s deconstruction job is the same evolutionary biologist at Harvard who recently supported Mayor Bloomberg’s drive to ban jumbo soda servings on health grounds. Dr. Lieberman observed in the New York Times, “We have evolved to need coercion.”
Do you see what I mean when I tell you they say one thing to the media but tell a much more complicated story when they think you’re not listening?
Image credit: Australopithecus afarensis, Wikicommons.