by Isaac Asimov
In the 1880s, a Dutch paleontologist, Marie Eugene Francois Thomas Dubois, got it into his head that the ancestors of human beings might be found in the East Indies (modern Indonesia), where great apes still flourished (and where he could work conveniently because those islands then belonged to the Netherlands). Surprisingly enough, Dubois, working in Java, the most populous of the Indonesian islands, did turn up a creature somewhere between an ape and a human! After three years of hunting, he found the top of a skull which was larger than an ape’s but smaller than any recognized as human. The next year he found a similarly intermediate thighbone. Dubois named his “Java man” Pithecanthropus erectus (“erect apeman”) (figure 16.4). Half a century later, in the 1930’s, another Dutchman, Gustav H. R. von Koenigswald, discovered more bones of Pithecanthropus, and they composed a clear picture of a small-brained, very beetling-brewed creature with a distant resemblance to Neanderthal.
Meanwhile other diggers had found, in a cave near Peking, skulls, jaws, and teeth of a primitive man they called Peking man. Once this discovery was made, it came to be realized that such teeth had been located earlier—in a Peking drugstore, where they were kept for medicinal purposes. The first intact skull was located in December 1929, and Peking man was eventually recognized as markedly similar to Java man. It lived perhaps half a million years ago, used fire, and had tools of bone and stone. Eventually, fragments from forty-five individuals were accumulated, but they disappeared in 1941 during an attempted evacuation of the fossils in the face of the advancing Japanese. In 1949, Chinese archeologists resumed digging, and fragments of forty individuals of both sexes and all ages have now been located.
Peking man was named Sinanthropus pekinensis (“China man of Peking”), but closer examination of more of these comparatively small-brained hominids (“manlike” creatures) made it seem that it was poor practice to place Peking man and Java man in separate genera. The German-American biologist Ernst Walter Mayr felt it wrong to place them in a separate genus from modern human beings, so that Peking man and Java man are now considered two varieties of the species Homo erectus, whose earliest members may have appeared 700,000 years ago.
It is unlikely that humankind originated in Java, despite the existence there of a small-brained hominid. For a while the vast continent of Asia, early inhabited by Peking man, was suspected of being the birthplace of human beings; but as the twentieth century progressed, attention focused more and more firmly on Africa, which, after all, is the continent richest in primate life generally and of the higher primates particularly.
The first significant African finds were made by two English scientists, Raymond Dart and Robert Broom. One spring day in 1924, workers blasting in a limestone quarry near Taungs in South Africa picked up a small skull that looked nearly human. They sent it to Dart, an anatomist working in Johannesburg. Dart immediately identified it as a being between an ape and a human, and called it Australopithecus africanus (“southern ape of Africa”). When his paper announcing the find was published in London, anthropologists thought he had blundered, mistaking a chimpanzee for an apeman. But Broom, an ardent fossil hunter who had long been convinced that human beings originated in Africa, rushed to Johannesburg and proclaimed Australopithecus the closest thing to a missing link that had yet been discovered.
Through the following decades, Dart, Broom, and several anthropologists searched for and found many more bones and teeth of South African apemen, as well as clubs that they used to kill game, the bones of animals that they killed, and caves in which they lived. Australopithecus was a short, small-brained creature with a snoutlike face, in many ways less human than Java man. But Australopithecus had more human brows and more human teeth than Pithecanthropus and walked erect, used tools, and probably had a primitive form of speech. In short, Australopithecus was an African variety of hominid living at least half a million years ago and definitely more primitive than Homo erectus.
There were no clear grounds for suspecting priority between the African and the Asian varieties of hominids at first, but the balance swung definitely and massively toward Africa with the work of the Kenya-born Englishman Louis Seymour Bazett Leakey and his wife Mary. With patience and persistence, the Leakeys combed likely areas in eastern Africa for early fossil hominids.
The most promising was Olduvai Gorge, in what is now Tanzania, and there, on 17 July 1959, Mary Leakey crowned a more than quarter-century search by discovering fragments of a skull that, when pieced together, proved to encase the smallest brain of any hominid yet discovered. Other features showed this hominid, however, to be closer to humans than to apes, for it walked upright and the remains were surrounded by small tools formed out of pebbles. The Leakeys named their find Zinjanthropus (“East African man,” using the Arabic word for East Africa) (figure 16.4).
Zinjanthropus does not seem to be in the direct line of ancestry of modern humans. Still older fossils, some 2 million years old, may qualify. These, given the name of Homo habilis (“nimble man”), were 4½-foot-tall creatures who already had hands with opposable thumbs which were nimble enough (hence, the name) to make them utterly like humans in this respect.
In 1977, the American archaeologist Donald Johanson discovered a hominid fossil that was perhaps 4 million years old. Enough bones were dug up to make up about 40 percent of a complete individual. It was a little creature about three and a half feet tall with slender bones. Its scientific name is Australopithecus afarensis, but it is popularly known as Lucy.
The most interesting thing about Lucy is that she is completely bipedal—as much as we are. It would seem that the first important anatomical characteristic that marked off hominids from apes was the development of bipedality at a time when the hominid brain was no larger than that of a gorilla. It might be argued, in fact, that the sudden and remarkable expansion of the hominid brain in the last million years came about as the result of bipedality. The forelimbs were freed to become delicate hands with which to feel and manipulate various objects, and the flood of information reaching the brain put a premium on any chance increase, which was then given survival value by the processes of natural selection.
It may be that Lucy represents the ancestors of two branches of the hominid line. On one side are various australopithecines, whose brains had a volume of between 450 and 650 cubic centimeters, and which became extinct about a million years ago. On the other side are the ancestral hominids, the members of genus Homo, which passed through Homo habilis, then Homo erectus (with a brain capacity of from 800 to 1,100 cubic centimeters), and then finally Homo sapiens (with a brain capacity of from 1,200 to 1,600 cubic centimeters).
Naturally, if we look beyond Lucy, we find fossils of animals that are too primitive to be called hominids, and we approach the common ancestor of the horninids, of which the living members are human beings, and the pongids (or apes), of which the living members are the chimpanzee, the gorilla, the orangutan, and several species of gibbon.
There is Ramapithecus, whose upper jaw was located in northern India in the early 1930s by G. Edward Lewis. The upper jaw was distinctly closer to the human than is that of any living primate other than ourselves; it was perhaps 3 million years old. In 1962, Leakey discovered an allied species which isotope studies showed to be 14 million years old.
In 1948, Leakey had discovered a still older fossil (perhaps 25 million years old), which was named Proconsul. (This name, meaning “before Consul” honored Consul, a chimpanzee in the London Zoo.) Proconsul seems to be the common ancestor of the larger great apes, the gorilla, chimpanzee, and orangutan. Farther back, then, there must be a common ancestor of Proconsul and Ramapithecus (and of the primitive ape that was ancestral to the smallest modern ape, the gibbon). Such a creature, the first of all the apelike creatures, would date back perhaps 40 million years.
PILTDOWN MAN
For many years anthropologists were greatly puzzled by a fossil that did look like a missing link, but of a curious and incredible kind. In 1911, near a place called
Piltdown Common in Sussex, England, workmen building a road found an ancient, broken skull in a gravel bed. The skull came to the attention of a lawyer named Charles Dawson, and he took it to a paleontologist, Arthur Smith Woodward, at the British Museum. The skull was high-browed, with only slight brow ridges; it looked more modern than Neanderthal. Dawson and Woodward went searching in the gravel pit for other parts of the skeleton. One day Dawson, in Woodward’s presence, came across a jawbone in about the place where the skull fragments had been found. It had the same reddish-brown hue as the other fragments and therefore appeared to have come from the same head. But the jawbone, in contrast to the human upper skull, was like that of an ape! Equally strange, the teeth in the jaw, though apelike, were ground down, as human teeth are, by chewing.
Woodward decided that this half-ape, half-man might be an early creature with a well-developed brain and a backward jaw. He presented the find to the world as the Piltdown man, or Eoanthropus dawsoni (“Dawson’s dawn man”).
Piltdown man became more and more of an anomaly as anthropologists found that, in all other fossil finds that included the jaw, jawbone development did keep pace with skull development. Finally, in the early 1950s, three British scientists—Kenneth Oakley, Wilfrid Le Gros Clark, and Joseph Sidney Weiner—decided to investigate the possibility of fraud. It was a fraud. The jawbone, that of a modern ape, had been planted.
The tale of Piltdown man is perhaps the best known and most embarrassing example of scientists being fooled for a long time by an arrant hoax. In hindsight, we can be astonished that scientists were fooled by so clumsy a jape, but hindsight is cheap. We must remember that in 1911 very little was known about hominid evolution. Today, a similar hoax would fool no knowledgeable scientist for a moment.
Another odd story of primate relics had a happier ending. In 1935, von Koenigswald had come across a huge but manlike fossil tooth for sale in a Hong Kong pharmacy. The Chinese pharmacist considered it a “dragon tooth” of valuable medicinal properties. Von Koenigswald ransacked other Chinese pharmacies and had four such molars before the Second World War temporarily ended his activities.
The manlike nature of the teeth made it seem that gigantic human beings, possibly 9 feet high, once roamed the earth. There was a tendency to accept this theory, perhaps, because the Bible says, “There were giants in the earth in those days” (Genesis 6:4).
Between 1956 and 1968, however, four jawbones were discovered into which such teeth would fit. The creature, Gigantopithecus, was seen to be the largest primate ever known to exist, but was distinctly an ape and not a hominid, for all its human-appearing teeth. Very likely it was a gorillalike creature, standing 9 feet tall when upright and weighing 600 pounds. It may have existed contemporaneously with Homo erectus and possessed the same feeding habits (hence the similarity in teeth). It has, of course, been extinct for at least a million years and could not possibly have been responsible for that biblical verse.
RACIAL DIFFERENCES
It is important to emphasize that the net result of human evolution has been the production today of a single species: that is, while there may have been a number of species of hominids, one only has survived. All men and women today, regardless of differences in appearances, are Homo sapiens; and the difference between blacks and whites is approximately that between horses of different coloring.
Still, ever since the dawn of civilization, human beings have been more or less acutely conscious of racial differences and usually have viewed other races with the emotions generally evoked by strangers, ranging from curiosity to contempt to hatred. But seldom has racism had such tragic and long-persisting results as the modern conflict between white people and black. (White people are often referred to as Caucasians, a term first used, in 1775, by the German anthropologist Johann Friedrich Blumenbach, who was under the mistaken impression that the Caucasus contained the most perfect representatives of the group. Blumenbach also classified blacks as Ethiopians and East Asians as Mongolians, terms that are still sometimes used.)
The racist conflict between white and black, between Caucasian and Ethiopian, so to speak, entered its worst phase in the fifteenth century, when Portuguese expeditions down the west coast of Africa began a profitable business of carrying off black Africans into slavery. As the trade grew and nations built their economies on slave labor, rationalizations to justify the enslavement of blacks were invoked in the name of the Scriptures, of social morality, and even of science.
According to the slaveholders’ interpretation of the Bible—an interpretation believed by many people to this day—blacks were descendants of Ham and, as such, an inferior tribe subject to Noah’s curse: “a servant of servants shall he be unto his brethren” (Genesis 9:25). Actually, the curse was laid upon Ham’s son, Canaan, and on his descendants, the Canaanites, who were reduced to servitude by the Israelites when the latter conquered the land of Canaan. No doubt the words in Genesis 9:25 represent a comment after the fact, written by the Hebrew writers of the Bible to justify the enslavement of the Canaanites. In any case, the point of the matter is that the reference is to the Canaanites only, and the Canaanites were certainly white. It was a twisted interpretation of the Bible that the slaveholders used, with telling effect in centuries past, to defend their subjugation of blacks.
The “scientific” racists of more recent times took their stand on even shakier ground. They argued that black people were inferior to white as obviously representing a lower stage of evolution. Were not a dark skin and wide nose, for instance, reminiscent of the ape? Unfortunately for the “scientific” racists’ case, this line of reasoning actually leads to the opposite conclusion. Black people are the least hairy of all human groups; in this respect and in the fact that their hair is crisp and woolly, rather than long and straight, they are farther from the ape than white people are! The same can be said of the black’s thick lips; they resemble those of an ape less than do the white’s thin lips.
The fact of the matter is that any attempt to rank the various groups of Homo sapiens on the evolutionary ladder is to try to do fine work with blunt tools. Humanity consists of but one species, and so far the variations that have developed in response to natural selection are superficial.
The dark skin of dwellers in the earth’s tropical and subtropical regions has obvious value in preventing sunburn. The fair skin of northern Europeans is useful to absorb as much ultraviolet radiation as possible from the comparatively feeble sunlight in order that enough vitamin D be formed from the sterols in the skin. The narrowed eyes of the Eskimo and the Mongol have survival value in lands where the glare from snow or desert sands is intense. The high-bridged nose and narrow nasal passages of the European serve to warm the cold air of the northern winter. And so on.
Since the tendency of Homo sapiens has been to make our planet one world, no basic differences in the human constitution have developed in the past and are even less likely to develop in the future. Interbreeding is steadily evening out the human inheritance. The American black is one of the best cases in point. Despite social barriers against intermarriage, nearly four-fifths of the black people in the United States, it is estimated, have some white ancestry. By the end of the twentieth century probably there will be no “pure-blooded” black people in North America.
BLOOD GROUPS AND RACE
Anthropologists nevertheless are keenly interested in race, primarily as a guide to the migrations of early human beings. It is not easy to identify specific races. Skin color, for instance, is a poor guide; the Australian aborigine and the African black are both dark in color but are no more closely related to each other than either is to the European. Nor is the shape of the head—dolichocephalic (long) versus brachycephalic (wide), terms introduced in 1840 by the Swedish anatomist Anders Adolf Retzius—much better despite the classifications of Europeans into subgroups on this basis. The ratio of head length to head width multiplied by 100 (cephalic index, or, if skull measurements were substituted, cranial index) served to divi
de Europeans into Nordics, Alpines, and Mediterraneans. The differences, however, from one group to another are small, and the spread within a group is wide. In addition, the shape of the skull is affected by environmental factors such as vitamin deficiencies, the type of cradle in which an infant sleeps, and so on.
But the anthropologists have found an excellent marker for race in blood groups. The Boston University biochemist William Clouser Boyd was prominent in this connection. He pointed out that blood groups are inherited in a simple and known fashion, are unaltered by the environment, and show up in distinctly different distributions in the various races.
The American Indian is a particularly good example. Some tribes are almost entirely O; others are O but with a heavy admixture of A; virtually no Indians have B or AB blood. An American Indian testing as a B or AB is almost certain to possess some European ancestry. The Australian aborigines are likewise high in O and A, with B virtually nonexistent. But they are distinguished from the American Indian in being high in the more recently discovered blood group M and low in blood group N, while the American Indian is high in N and low in M.
In Europe and Asia, where the population is more mixed, the differences between peoples are smaller, yet still distinct. For instance, in London 70 percent of the population has O blood; 26 percent, A; and 5 percent, B. In the city of Kharkov, Russia, on the other hand, the corresponding distribution is 60, 25, and 15. In general, the percentage of B increases as one travels eastward in Europe, reaching a peak of 40 percent in central Asia.
Now the blood-type genes show the not-yet-entirely-erased marks of past migrations. The infiltration of the B gene into Europe may be a dim mark of the invasion by the Huns in the fifth century and by the Mongols in the thirteenth. Similar blood studies in the Far East seem to indicate a comparatively recent infiltration of the A gene into Japan from the southwest and of the B gene into Australia from the north.
