Blueprints: Solving the Mystery of Evolution
By Maitland A. Edey and Donald C. Johanson
Little Brown, 416 pages, $22.95
Appalled by the puny acceptance of the scientific answer to that most profound question-where do we come from?-veteran journalist Maitland Edey and ace hominid fossil-finder Donald Johanson have penned a popular-science blockbuster.
”Blueprints,” which Johanson describes as ”a cram course in evolution,” is more ambitious than their 1981 bestseller, ”Lucy: The Beginnings of Humankind.” That classic recounted Johanson`s discovery of a 3.5-million-year-old woman in the sun-baked badlands of Ethiopia, an erect-walking primate that most scientists now accept as the mother of us all. But Johanson really used Lucy as an excuse for a rollicking and gossipy survey of the science of fossil man, paleoanthropology.
At the time he stumbled over Lucy in 1974, Johanson was a young, American-trained upstart in what traditionally has been a pompous European science. He took delight in airing all the dirty linen, presenting the search for human origins as a crucible where titanic egos clash and crackpots often have triumphed over brilliant minds who lacked political connections and dared to unearth unsavory, socially unacceptable facts.
If you can abide their format, a chatty historical narrative periodically interrupted by caucuses between the authors, ”Blueprints” is as much fun as ”Lucy.” And, as far as one can tell, it represents the first attempt to distill for the lay reader the entire case for evolution, from science`s first awareness of the process to the advent of modern genetic engineering-which promises, or threatens, to alter evolution`s course and allow us to control our own biological destiny.
Today, argue Edey and Johanson, the general outlines of evolution theory are accepted by all ”respectable” scientists: ”They still fight over details, but the grand scheme seems firmly locked in place-for everyone except the Creationists who, in the face of a Himalaya of evidence, still deny the possibility of evolution.”
Evolution receives short shrift in school curricula, which to these authors smacks of hypocrisy. ”You can`t,” they assert, ”accept one part of science because it brings you good things like electricity and penicillin, and throw away another part because it brings some ideas you don`t like about the origin of life.”
Yet as many as half of all Americans, according to polls, don`t buy it. Large numbers of people either are unaware of, or reject, the theory of Charles Darwin, who showed that all living things change and adapt with time and circumstances. And few non-scientists appreciate Gregor Mendel, the reclusive genius who, by quietly tending to his monastery garden, put Darwinism on the path that ultimately led to DNA and what biologists call the ”modern synthesis”-meaning that Darwinism and Mendelism are the two main aspects of evolution and that one can`t exist without the other.
Edey and Johanson trace the theory back to the thinkers who first began to discern relationships among the countless species in nature-such great sorters, cataloguers, classifiers and observers as Linnaeus, Buffon, Cuvier, Lamarck and James Hutton, the brooding Scot whose principle with the jawbreaking name-uniformitarianism-simply means that because processes are gradual, or uniform, what is now taking place on the Earth`s surface is no different from what always has taken place there.
The authors move from the gloomy Thomas Malthus and his theory of the economic survival of the fittest to Darwin and his voyage aboard the Beagle, which gave birth to the blazing insight that species are not fixed in time and place but are constantly changing;that aside from rare identical twins, no two living individuals-plant or animal-are identical; that the elements of variation are inherited; and that if such natural selection occurs long enough, it will result in new species that take advantage of the best their forebears had to offer.
”Stated as an argument,” the authors write, ”and buttressed by a mountain of evidence, the theory of evolution carries with it a sense of majesty and inevitability.” Yet even Darwin instinctively sensed the unabating furor the notion would provoke and was so fearful of his theory that he turned away to study barnacles for 10 years. Only when it appeared that Alfred Russel Wallace was about to scoop him was Darwin spooked into publishing ”On the Origin of Species.”
At this juncture, Johanson and Edey urge readers to get small, to examine the mechanics of evolution churning away at the cellular, chromosomal and molecular levels. Aside from some unfortunate silliness-trying to explain Mendel`s discovery that traits are not blended but passed on in discrete packets, they speak of what happens if you mix chicken and ham pate-Edey and Johanson simplify the complexities as clearly as anyone ever has.
They chronicle the great detective stories that have occurred in unlikely settings, such as the famous ”Fly Room” at Columbia University, where genetic mutations were first catalogued and linked to specific fruit fly chromosomes by Thomas Hunt Morgan and his students. They profile the Petri-dish sagas of such great bacterial chemists as the elfin and meticulous Oswald Avery-who, like Sherlock Holmes, eliminated all possibilities until only one remained, proving that it was the DNA in dead pneumonia germs that had such great heritable power as to transform harmless pneumococcus cousins into killers.
After surveying the architecture of genes via James Watson and Francis Crick; exploring their chemical nature with Matthew Meselson, Franklin Stahl and Arthur Kornberg; and recounting the cracking of the genetic code by the ubiquitous Crick, Marshall Nirenberg and Johann Matthaei, the authors finally move to the new breed of synthesizers who are intent on defining the molecular origins of life.
Johanson is particularly at home here, explaining his lasting rivalry with the clan of the late Louis Leakey, who refuse to accept Lucy and similar apefolk as human ancestors. The Leakeys still promote the family theory that someday an independent, 15-million-year-old ancestral line that leads to humanity will be discovered.
Molecules don`t seem to lie, though, and the evidence of blood proteins, pioneered by biochemist Vincent Sarich, suggests that humans, gorillas and chimpanzees shared a common ancestor as recently as 5 million years ago. The first whispers of humanity began to be heard then, and today we are-in genetic terms-about as different from gorillas and chimps as they are from each other. What that suggests to Johanson is that cultural evolution is proceeding at a much brisker clip than our brain can deal with: ”All we can say right now is that our technology is evolving a great deal faster than we are psychologically and emotionally, and therefore faster than our ability to handle that technology.”
Unfortunately, we still make our most critical decisions out of passion, not out of reason, ”because in our guts we are passionate stone-age people.” We have not exorcised fear, wrath, jealousy or revenge, note Edey and Johanson. And they suggest-only half-kidding, I believe-that the goal of the New Biology might be to actually create a better adapted humanity.
”Improbable or not, this is certainly a matter that humans will find themselves thinking about more and more as the choices become harder,” the authors predict. ”For we are now on the verge of having the scientific skills to do something about it.”
