In his 1859 book, On the Origin of Species, Charles Darwin offered a novel explanation for the earth's diversity of plants and animals. All the myriad forms, he wrote, came into being through "natural selection" much as new varieties of dogs and pigeons are brought into being through artificial selection. Natural selection, at first called a theory, eventually won a place in world thought as an established principle. The transformation of genetic lines through time by means of natural selection came to be known as evolution.
Darwin's idea emerged in a century when leading scientists were beginning to doubt current estimates of the earth's youthfulness (a few thousand years). They were also learning that certain faunas and floras which had been fossilized long ago differ greatly from those still alive. They were beginning to recognize the what of changes in life's patterns but were still unclear as to the how and why. They could only imagine the hidden forces that might have caused some species to vanish from the fossil record while allowing others to survive.
Darwin based his explanation of three known qualities of living organisms. First, no two individuals are identical. (Today, we know the main reasons for variation, including genetic mistakes and genetic drift, the random shuffling of genes during reproduction, and hybridizing in the wild.) Second, every organism produces more offspring than it needs to replace itself. Witness the male rabbit, successfully fertilizing forty females in one day, and the oyster, shedding 60 million eggs in a season. Third, every organism is continuously engaged in what Darwin called the struggle for life--the struggle to find food and shelter; the struggle against pathogens, predators, and competitors; and the struggle against environmental hazards such as drouth, storm, flood, wildfire, and frost.
So, Darwin reasoned that the interplay among these forces brings about "the preservation of favoured races" or (in later editions of The Origin) "survival of the fittest." In this context, the fittest are simply the ones that contributed most to the gene pools of later generations. Fitness can thus be judged only in hindsight, by studying the success or failure of the individual genetic line through geological time. Darwin's conclusion "was essentially statistical and based on population dynamics" (Nobel prize-winning immunologist Sir Peter Medawar).
Natural selection has been proved and its pace has been measured in at least a hundred studies of plants and animals in the wild and in studies of microbes in cultures. For example: English sparrows were brought to eastern North America around 1850. In the next century and a half, their descendents spread rapidly over the entire continent from Canada to Central America, meanwhile evolving into three distinct varieties which are now fully equivalent to wild zoological subspecies. And, in test-tube studies (where bacteria can clock up a new generation every 3.5 hours) scientists recently ran natural selection "fast- forward." The bacteria, which at the start of the run had been randomly divided into three populations, evolved after ten years into three genetically distinct strains.
In certain intellectual backwaters of America, however, Darwin's idea is still rejected by millions who insist that only Almighty God could have created the splendid Circus of Life in which Homo sapiens plays the star performer. These millions--the "creationists"--argue that, because a clear explanation for life's rich diversity was written in the Book of Genesis nearly two thousand years ago, all secular revisions should be ignored or even opposed.
But the creationists' point is rebutted by men and women who hold that the Genesis story is only a myth. They see no need to bring magic into the debate; they choose a natural over a supernatural explanation. As did Darwin himself. He died disillusioned with divine intervention in earthly matters. "There seems to be," he wrote, "no more design in the variability of organic beings and in the action of natural selection, than in the course which the wind blows."
Curiously, he had written earlier (in the first edition of The Origin) that life had "been breathed into a few forms or into one . . ." In the second (1860) edition he added, to the word "breathed," the words "by the creator." Some believe that the kindly Darwin made this addition to reassure his deeply devout wife that evolution is, after all, the handiwork of a Purposeful Mind.
Harvard University's Stephen Jay Gould points to "the embarrassing paradox of a technological nation [America] entering a new millennium with nearly half its people actively denying the greatest biological discovery ever made." He is referring, I think, to a recent survey of more than 1,200 college freshmen, in ten different schools, which indicated that 45 percent were skeptical of the "theory" of evolution.
Should we condemn those who reject Darwin's grand idea or, rather, should we pity them in their ignorance? Should we condemn American education at elementary and middle-school levels for failing to stimulate intellectual curiosity? Answers to these questions will vary with one's cultural background.
John Maynard Smith, among the greatest of twentieth-century evolutionary scholars, wrote in 1993 that Darwin's idea "is the only workable explanation that has ever been proposed for the remarkable fact of our own existence, indeed the existence of all life wherever it may turn up in the universe."
Natural selection, while deceptively simple at first glance, still poses many problems in its finer machinery. The evolutionary biologists, historians, and philosophers who are searching for solutions are surely reaching levels of spiritual exhilaration that others reach in probing the mysteries of religion.
After earning a Ph.D. in Zoology at the University of Washington, Victor Scheffer entered service in 1937 in the federal Bureau of Biological Survey as a wildlife management biologist. On a National Science Foundation grant, he studied at Cambridge University in 1956-57, where he wrote his first book, Seals, Sea Lions, and Walruses (1958).
Eleven other books, most of them dealing with outdoor values and biology, would follow. The Year of the Whale (1969) helped spark the marine mammal conservation movement of the 1970s.
Dr. Scheffer taught at the University of Washington as a part-time lecturer from 1966 to 1972. He served as chair of the first U.S. Marine Mammal Commission from 1973 to 1976.
His honors include awards from the Department of the Interior, the John Burroughs Memorial Association, the Nature Conservancy, the Society for Conservation Biology, the American Society of Mammalogists, and the Society for Marine Mammalogy.
Norton's Darwin Just Released
The Third Edition of Norton's Darwin (Indiana University), edited by poet and Darwin scholar Philip Appleman, a Foundation member, has just been released.
The critical edition examines the history of ideas preceding and following the watershed of the Origin of Species, Prof. Appleman writes, and "situates the current evolution controversies in their rich and intriguing context."
Although the 1970 Norton Critical Edition served for 30 years as a standard college textbook, the third edition is so radically revised that "it is virtually a brand new book," and of interest to the general reader.
New work is included by Richard Dawkins, Edward O. Wilson, Kevin Padian, Eugenie C. Scott, Steven Pinker, Daniel Dennett, Michael Ruse, Frans de Waal, Noretta Koertge, George C. Williams, George Levine, Stephen Jay Gould, Gillian Beer, Ernst Mayr, and many others. A new introduction by Philip Appleman is included.
Celebrate Darwin Day
Born February 12, 1809
". . .For my part I would as soon be descended from [a] baboon . . . as from a savage who delights to torture his enemies . . . treats his wives like slaves . . . and is haunted by the grossest superstitions."--Darwin, Descent of Man
"I can indeed hardly see how anyone ought to wish Christianity to be true; for if so the plain language of the text seems to show that the men who do not believe, and this would include my Father, Brother and almost all my best friends, will be everlastingly punished.
"And this is a damnable doctrine."
". . . The old argument of design in nature, as given by Paley, which formerly seemed to me so conclusive, fails, now that the law of natural selection has been discovered. We can no longer argue that, for instance, the beautiful hinge of a bivalve shell must have been made by an intelligent being, like the hinge of a door by a man. There seems to be no more design in the variability of organic beings and in the action of natural selection, than in the course which the wind blows. Everything in nature is the result of fixed laws. . .
"The state of mind which grand scenes formerly excited in me, and which was intimately connected with a belief in God, did not essentially differ from that which is often called the sense of sublimity; and however difficult it may be to explain the genesis of this sense, it can hardly be advanced as an argument for the existence of God, any more than the powerful though vague and similar feelings excited by music. . .
. . .The mystery of the beginning of all things is insoluble by us; and I for one must be content to remain an Agnostic.--Darwin, Autobiography (1958 version, restoring the original omissions from Darwin's Life and Letters of Charles Darwin, published posthumously in 1887)