In 1856, a gang of quarrymen in the Neander Valley of Germany uncovered the fossilized remains of a skeleton. Something about those bits and pieces of petrified bone intrigued the workers, who brought them to a local school teacher, Carl Fuhlrott. He recognized a skull that, while seemingly human, had features not observed in modern people, such as exaggerated eyebrow ridges and a long sloping forehead.
That was several years before Charles Darwin published his discovery that plants and animals developed out of earlier forms of life. But clearly the idea of evolution was in the air. For Fuhlrott correctly guessed that the fossil represented a primitive form of humanity that had roamed Central Europe before the birth of the human race as we know it.
Ever since, Neanderthal Man, as that fossil came to be called, has fascinated homo sapiens, as anthropologists designate modern man. Working from Fuhlrott`s fossil and subsequent finds, scientists generated an artist`s reconstruction that quickly became the popular image of the caveman.
”What child hasn`t pressed his nose to the glass of a museum diorama, mesmerized by a stoop-shouldered Neanderthal woman cuddling an infant so tantalizingly like, yet somehow different, from his own baby brother or sister?” Arthur Jelinek recently reminded an audience at the Field Museum of Natural History.
Jelinek, an anthropolgist at the University of Arizona, was part of a group of leading scientists brought to Chicago by the museum for a day-long debate on the Neanderthals` fate.
The conference was occasioned by the publication, three years ago, of a paper in which two British scientists, C.B. Stringer and Peter Andrews, proposed a revolutionary interpretation of human evolution.
According to the standard view, modern man developed from distant apelike ancestors over millions of years, through intermediate forms like the Neanderthals. Supposedly, the later stages of that evolutionary process took place not just once, but several times on different continents, which is why we see current racial types, such as Caucasian, African, East Asian.
By contrast, Stringer and Andrews, who are on the staff of the British Museum, argue that racial differences are not the results of critical steps in the evolutionary process. They say the emergence of modern man occurred only once and not so very long ago, at least according to the yardsticks measuring vast stretches of prehistoric time.
The British researchers say all human beings may, in fact, be the descendants of a single mother, a kind of evolutionary Eve who lived about 200,000 years ago in southern Africa. Through hundreds of generations, her offspring spread out to populate the globe; hence Stringer and Andrews` theory was quickly dubbed the ”Out of Africa” hypothesis.
Ironic epilogue
Stringer, who spoke at the Field Museum`s symposium, says he and his partner are dispassionate scientists who simply follow the track of the data, irrespective of political or ideological consequences. Yet he also recognizes that, if validated, the Out of Africa hypothesis will provide an ironic epilogue to one of the uglier themes of modern history.
W.E.B. Du Bois, the great black American scholar and founder of the NAACP, once observed: ”The problem of the 20th Century is the problem of the color line.” Indeed, the U.S. has yet to recover from our founding fathers`
assumption that they were entitled to enslave people of a different race. South Africa is struggling to undo the harm and hurt of apartheid. Hitler`s ideas about a supposed master race brought death and suffering to uncounted millions.
Yet if Stringer and Andrews are correct, there is only one human race. Whatever the color of our skin, we are all kith and kin, descendants of common ancestors.
”When I spoke at an American university, a young black student asked:
`Is what you are saying that we are all Afro-Americans or Afro-Europeans or Afro-somethings?”` Stringer recalled, after his presentation. ” `Yes,` I replied, `that pretty much sums up our theory.”`
His theory, Stringer added, also demotes Neanderthal Man from a critical position in the evolutionary chain. If the Out of Africa hypothesis is correct, then Fuhlrott`s famous fossil represents only a kind of evolutionary cul-de-sac, even though its discovery first inspired the hunt for mankind`s ancestry.
Stringer notes that evolution is a hit-or-miss process. When an animal or plant species begins to mutate, several new forms often emerge and co-exist, side by side, for a while. Eventually only the most successful variant survives what Darwin called the ”struggle for existence.”
Similiarly, according to the Out of Africa hypothesis, Neanderthal Man was a kind of early, experimental model of humanity. He enjoyed his moment under a European sun, while modern man was still developing in Africa; then his line was extinguished. Stringer adds that emotionally he didn`t like coming to that conclusion.
”I got interested in science as a boy of 8, when I gave a school report on Neanderthal Man,” Stringer recalled. ”I thought he`d gotten a raw deal, being called `primitive` and `savage.` So I talked to the class about Neanderthal Man like he was a member of the family.”
That viewpoint, Stringer added, accorded nicely with the perspective on human evolution he subsequently received as a university student. He was taught that in 1868, a dozen years after the Neander Valley discovery, some railway workers came across another set of fossils at a rock formation known as Cro-Magnon, in southwestern France. But while those bones seemed almost as ancient as Neanderthal Man, their form was quite different.
The Neanderthals had large, powerful hands and thick bodies, as if their very survival depended upon brute strength. Cro-Magnon Man, by contrast, had a leaner, more subtle build. His facial structure more closely resembled a contemporary human`s.
So it seemed natural to conclude that the evolution of man was a three-step process: The Neanderthals begat Cro-Magnon Man who begat modern man. That hypothesis also accorded with a built-in bias of early anthropology, a discipline born when Europeans were convinced of their supremacy. So the scientific imagination of early anthropologists was primed to expect that Europe would be modern man`s birthplace.
”Human evolution was seen as a sort of `March of Time` newsreel,” noted Rebecca Cann, a key suporter of the Out of Africa hypothesis, ”in which man got whiter and whiter and whiter.”
Begining at the end of the 19th Century, Stringer recalled, archaic human fossils were also uncovered in Asia and Africa. Some seemed more primitive than others, just as Neanderthal Man was obviously more primitive than Cro-Magnon Man. Once again, the discoverers of those new fossils assumed that they, too, represented evolutionary sequences from which the peoples of Asia and Africa had descended.
”Anthropology is very proprietary,” Stringer observed. ”My scientific elders each promoted the materials they excavated as the key to understanding human evolution. They weren`t happy when a few upstarts like myself devised an alternative theory. For the first five years or so after proposing the Out of Africa scenario, I`d go to a scientific convention and find myself speaking to audiences of only a very few people.”
Even as a graduate student, Stringer continued, he was troubled by the standard senario of human evolution. Darwinian theory teaches that the form of a species is an adaption to its environment: Polar bears are white because, against the backdrop of Arctic ice and snow, that gives them an advantage in sneaking up on their prey. If human beings had evolved separately at various places on Earth, Stringer reasoned, wouldn`t each human community be distinctive, having been separately molded by the special character of its environment?
A critical migration
Beginning about 1974, Stringer, joined by Andrews, systematically restudied fossil remains of early man found in Asia, Africa and Europe.
”Once you get behind skin color and start comparing skeletal types, modern human beings, wherever on Earth they live, are quite similar to each other,” Stringer says. ”In fact, the so-called `races` of mankind are much closer to each other than any of them is to their fossil ancestors of, say, 200,000 years ago.”
Stringer and Andrews proposed a total reworking of the hypothetical sequence of human evolution. By that point, fossil discoveries in Africa had virtually convinced anthropolgists that man`s most distant ape-like ancestors emerged on that continent between 6 and 10 million years ago. According to the British researchers, the evolutionary descendants of those early humaniod creatures divided into two. One group migrated about 1 million years ago to the other continents, giving rise to the Neanderthals of Europe and similar archaic fossil men of other regions.
Another group of humanoids remained in Africa, and there evolved into modern man somewhere between 100,000 and 200,000 years ago. Then part of that group also left its homeland for Europe and Asia, where it supplanted more primitive forms of humanity, like the Neanderthals.
That senario, though, isn`t convincing to Milford Wolpoff, professor of anthropology at the University of Michigan, and the leading defender of a more traditional view. At the Field Museum`s symposium he argued that there was only one migration from Africa, about 1 million years ago. All subsequent changes in the forms of mankind took place separately on each of the different continents. After the meeting, Wolpoff noted that Stringer`s hypothesis might be winning converts not because of its scientific validity, but because it fits academia`s prevailing winds.
”Underlying this debate is a set of attitudes towards race,” Wolpoff explained. ”In the 1960s, anthropolgists recoiled from the field`s earlier Eurocentrism and proclaimed: `There is no such thing as race.` Now by arguing for multiple evolutions of man, we-the people on my side of the argument-seem to be bringing back the concept of race.”
Stringer`s views received their most powerful support from Rebecca Cann, the leading practitioner of a new approach to palaeontology that looks for clues not in fossils but in the genetic structure of modern peoples. Her own work, Cann explained to the Field Museum audience, builds on that of contemporary biochemistry, which she says has established that human genes have a constant rate of evolution. By using that ”genetic clock,” it can be determined how long ago any two living individuals shared a common ancestor.
Along with other graduate students of the University of California at Berkeley, Cann measured the genetic material, DNA, of people around the world. They found that Africans have the greatest genetic variety, which meshed with Stringer`s hypothesis that modern man has lived longer there than on other continents. Cann`s group also reconstructred a family tree linking all living human beings to a common ancestor, who lived about 200,000 years ago, probably in southern Africa.
”The tree has 15 deep branches, all of which lead to Africans,” noted Cann, who is now a professor at the University of Hawaii. ”Viewed this way, the non-Africans stem on their maternal side from shallow branches and are mere twigs on the big tree that links us all to a common ancestor, our Lucky Mother.”
Wolpoff, though, questions the validity of the ”genetic clock.” He believes the question of the Neanderthals` fate and modern man`s genesis awaits future archeological discoveries.
By contrast, Stringer is convinced that Cann`s approach is the direction in which palaentology must now move. The fossil record remains tantalizingly thin. Some new bones have been uncovered and presented as evidence of separate evolutionary lines. Yet, Stringer notes, their anatomical interpretation is clouded by subjectivity: One anthropologist sees archaic features, where a colleague`s eye is drawn to signs of modernity. Unfortunately, modern carbon- dating techniques are not effective for the period in question.
”Rebecca Cann`s group has already analyzed 4,000 samples of human DNA, and not one of them has proven incompatible with the Out of Africa
hypothesis,” Stringer noted. ”That`s a large number, especially considering the data that traditional anthropolgists work with. In all the years since the discovery of Neanderthal Man, we haven`t dug up nearly so many human fossils.”
