Lone Survivors (3 page)

A replica of the jawbone unearthed in the Mauer sandpit near Heidelberg in Germany in 1907, together with one of the Boxgrove incisor teeth.

Suggestions that Europe may have hosted even more primitive human relatives started to emerge from a gravel pit at Piltdown in southern England in 1912, giving rise to yet another species called “
Eoanthropus dawsoni
” (“Dawn Man of Dawson”—Charles Dawson being the principal discoverer). Parts of a thick but large-brained skull, coupled with a distinctly apelike jaw, turned up there with ancient animal fossils and primitive stone tools, suggesting an age as great as that of Java Man. Africa had nothing to compare with these burgeoning finds, but that finally began to change in the 1920s. However, circumstances were such that these first finds still failed to switch the focus of human origins to Africa.

The Broken Hill (Kabwe) skull, discovered in 1921, was the first important human fossil from Africa, but it was a puzzling find. Although it was assigned to the new species “
Homo rhodesiensis
” by Sir Arthur Smith Woodward of the British Museum, the Czech-American anthropologist AleÅ¡ Hrdli
č
ka dubbed it “a comet of man's prehistory” because of the difficulty in deciphering its age and affinities. The skull was found in cave deposits that were being quarried away during metal ore mining, in what is now Zambia (then the British colony of Northern Rhodesia). It's one of the most beautifully preserved of all human fossils, but it displays a strange mixture of primitive and advanced features, and its face is dominated by an enormous brow ridge glowering over the eye sockets. And because it was found during quarrying, which eventually destroyed the whole Broken Hill mine, its age and significance remain uncertain even today (but see the final chapter for the latest developments).

Three years later an even more primitive find was made in a limestone quarry at Taung, South Africa—a skull that looked like that of a young ape. It was studied by a newly established professor of anatomy in Johannesburg, named Raymond Dart, and in 1925 he published a paper in the scientific journal
Nature
, making some remarkable claims about the fossil. He argued that it showed a combination of ape and human features, but that its teeth, brain shape, and probable posture were humanlike. Dart named it
Australopithecus africanus
(“Southern Ape of Africa”), and he declared that it was closely related to us, and even a potential human ancestor. Dart's claims were treated with great skepticism by the scientific establishment, particularly in England. This was partly because of judgments about Dart's youth and relative inexperience, and partly because the fossil was that of a child (young apes may look more “human” than adult apes). Others thought that the finds from Java, Heidelberg, and Piltdown provided much more plausible ancestors than
Australopithecus africanus
. And finally, the location and estimated age of Taung also counted against it.

No one (not even Darwin and Huxley) had considered southern Africa as a location for early human evolution, and as the Taung skull was guessed to be only about 500,000 years old, it was thought too recent to be that of a genuine human ancestor. Instead, it was considered to represent a peculiar kind of ape, paralleling humans in some ways. We now know, of course, that the australopithecines represented a long and important phase of human evolution that lasted for over 2 million years, and which is recognized at sites stretching from Chad in the Sahara to many more in eastern and southern Africa. And we have also known since their exposure in 1953 that the misleading Piltdown remains were fraudulent and had nothing to do with our ancient ancestry.

Other finds made at this time continued to keep the focus outside of Africa, and those made in cave deposits at Zhoukoudian near Beijing from 1921 onward began to reveal a Chinese counterpart to Java Man initially dubbed “
Sinanthropus pekinensis
” (“Chinese Man of Peking”). Systematic excavations carried out from 1927 until the present day have yielded many skull and body parts of humans who lived there about half a million years ago, people who resembled the growing collection of fossils from Java closely enough for them to be eventually grouped in the single species
Homo erectus
. This species is a crucial one for studies of our origins, because it's at the heart of radically different views of our evolution that have emerged over the last seventy years or so. Most anthropologists recognize the existence of at least two human species during the last million years—the extinct
Homo erectus
and our own species,
Homo sapiens
—but there are very different views on how these species are related.

Franz Weidenreich and some of the “Peking Man” fossils of
Homo erectus
that inspired him to create an early version of the Multiregional model of human origins.

What is now known as the Multiregional model of modern human origins was first proposed in the 1930s by Franz Weidenreich, a German anthropologist, who based many of his arguments on studies of the Zhoukoudian
Homo erectus
fossils. Weidenreich suggested that
Homo erectus
gave rise to
Homo sapiens
across its whole range, which, about 1 million years ago, included Africa, China, Indonesia, and perhaps Europe. In his view, as the species dispersed around the Old World (it's not known from regions such as Australia and the Americas), it developed the regional variation that lies at the roots of modern “racial” differentiation. Particular features in a given region persisted in the local descendant populations of today. For example, he argued from the fossils that Chinese
Homo erectus
specimens had the same flat faces and prominent cheekbones as modern oriental populations, while Javanese
Homo erectus
had robustly built cheekbones and faces that jutted out from the braincase, characteristics argued to be especially marked in modern Australian Aborigines.

At the other extreme from Weidenreich's Multiregional model was the view that the special features of modern humans (such as a high forehead, a chin, and a slender skeleton) would have required a long time to evolve, and hence the line leading to
Homo sapiens
(the “pre-
sapiens
” lineage) must have been very ancient and developed in parallel with large-browed and robust forms such as
Homo erectus
and the Neanderthals. This is an old idea, which came to prominence early in the twentieth century through influential researchers like Marcellin Boule (France) and Arthur Keith (United Kingdom), and aspects of it were taken up later by Louis Leakey, working in Kenya and Tanzania. The supporting evidence came and went through the last century, including at times specimens like Piltdown and the modern-looking Galley Hill skeleton from Kent—the former now known to be a fake and the latter wrongly dated.

Between the extremes of Multiregionalism (which potentially included every human fossil in our ancestry) and the Pre-
sapiens
model (which excluded most of them), there were intermediate models, ones which featured early Neanderthals in the story. The critical fossils this time were from Mount Carmel in what was then Palestine. They were discovered by an international expedition excavating a series of caves near Haifa during the late 1920s and 1930s. In two of the caves, Skhul and Tabun, they found human fossils that had apparently been intentionally buried. Moreover, they were associated with the kinds of stone tools that in Europe were associated with the Neanderthals. And yet the fossils seemed to show mixtures of Neanderthal and modern characteristics, so how should they be interpreted? In the 1930s there were no accurate methods of dating available, and so the Tabun and Skhul fossils were assumed by their describers, Theodore McCown and Arthur Keith, to be roughly contemporaneous with each other. Some suggested that the finds might represent hybrids between moderns and Neanderthals, but McCown and Keith preferred to regard them as members of a single but variable ancient population, perhaps one close to the divergence of the Neanderthal and modern lines. (In fact Keith could not quite abandon his pre-
sapiens
leanings and thought that they were still probably off the line leading to us, because of their Neanderthal features.)

Louis Leakey with the Olduvai Gorge “
Zinjanthropus
” skull, which his wife, Mary, discovered in 1959. It was the first important fossil to be dated by the potassium-argon method.

But others saw them as evidence for a pre-Neanderthal rather than pre-
sapiens
ancestry for modern humans, with the late or “classic” Neanderthals subsequently heading off the main line to the sidings of extinction. Following this line of argument, the American paleoanthropologist F. Clark Howell developed a neat scenario during the 1950s where “unspecialized Neanderthals” about 100,000 years ago became isolated in Europe by the last Ice Age and evolved away from
Homo sapiens
. At the same time, those in the Middle East (such as Tabun) evolved toward modern humans via forms like those found at Skhul. Then, to complete the story, about 35,000 years ago these Middle Eastern “proto–Cro-Magnons” migrated into Europe and replaced their European Neanderthal cousins.

In contrast to this Early Neanderthal model of modern human origins, which gave the Neanderthals at least a bit part in our evolution, there were two developments out of Weidenreich's Multiregionalism after his death in 1948 that returned the Neanderthals to a central role in our evolution, and in one case even extended their role globally. The American anthropologist Carleton Coon used new fossil material to develop a comprehensive global scheme of the evolution of five different lineages of
Homo erectus
, two in Africa, and one each in Europe, China, and Australia. These five lineages evolved largely independently to become what Coon regarded as the modern races of
Homo sapiens
: “Capoid” (the Bushman of South Africa and related peoples), “Negroid,” “Caucasoid,” “Mongoloid,” and “Australoid.”

In this respect, Coon differed fundamentally from his mentor, since Weidenreich considered human evolution to consist of a network of lineages constantly exchanging genes and ideas, whereas Coon was quite frank about the divided lineages and the implications of their inferred different rates of evolution: “Wherever
Homo
arose, and Africa is at present the most likely continent, he soon dispersed, in a very primitive form, throughout the warm regions of the Old World … If Africa was the cradle of mankind, it was only an indifferent kindergarten. Europe and Asia were our principal schools.”

The American paleoanthropologist C. Loring Brace gave Weidenreich's ideas a distinctly Neanderthal twist by arguing that
Homo erectus
evolved to modern humans in each part of the populated world by passing through a “neanderthaloid” phase. In essence, according to Brace, the Neanderthals and equivalent ancient people across the inhabited world used their front teeth as tools for manipulating food and materials, and this is what produced their especially prominent midfaces, large incisor teeth, and distinctive skull shape. When more advanced tools of the Upper Paleolithic (Upper Old Stone Age) were invented about 35,000 years ago, demands on the teeth and jaws were lifted, and so the face and skull were transformed into the shape we have today.