New evidence on origin of man

Press, Volume CXI, Issue 32703, 4 September 1971, Page 11

New evidence on origin of man

(By

BJORN KURTEN)

CAMBRIDGE. Is man descended from the apes? Recently, it was still thought that our ancestors branched off something pretty close to the gorillas and chimps, as late as the Ice Age. Now, for the first time, fossil evidence is accumulating on man’s early origins, and as the pieces fall into place, a very different solution is taking shape. We might even wonder whether it was the aples that descended from man’s early ancestors, rather ■ han the other way around. Man differs from his nearest zoological relatives, the ipes that descended from cal traits: his big brain, his fully erect posture, and his particular set of teeth with small incisors and eye-teeth. The big brain was the last to evolve; in fact our brain capacity tripled during the Ice Age. The upright posture came earlier, for the smallbrained humans of more than a million years ago were already fully erect. The human teeth are our oldest heritage; they can be traced back perhaps as much as 30 tillion years.

The ape-man Until quite recently, the nost primitive man-like being known was Australopithecus of'Africa. He has been called an “ape-man” but this is misleading. True, his small brain and protruding jaws give him a superficially ape-like countenance; but this is just his primitiveness showing through. When you go to the details, Australopithecus is a man, with small front teeth and eye-teeth; his molars are bigger than ours but that is not an ape-like characteristic. When did Australopithecus live? New discoveries have been pushing back his beginning date far beyond the two million years that is the starting date for the famous Olduvai Gorge sequence in Tanzania; and now, Harvard’s Bryan Patterson has announced the discovery of a jaw from Lothagam Hill south of Lake Rudolf, in deposits dating back more than five million years. It is now evident that proto-men of the Australopithecus line existed in Africa for many million years/ And, as we trace them backward in time, they do not really become more ape-like. Instead, we find the ancestral Ramapithecus, which lived in Africa, Europe and Asia during the time range 14

to 10 million years ago; the African record may- go still further back, up to 20 million years or so. Still incompletely known, this creature, the size of a five- or six-year-old child, is known to have had the small incisors and eyeteeth which suggest it may have given rise to Australopithecus. But in contrast with savanna - dwelling Austra-

lopithecus, little Ramapithecus appears to have been a denizen of the forest; and we may reasonably’ suspect that it still spent much of its time in the trees. Distinct groups What about the ancestry of Ramapithecus? The bones of very early ape- or man-like creatures have been found at Fayum in Egypt, where they were deposited more than 30 million years ago by the proto-Nile of the time. And here again, as in later times, are found two distinct groups. In one we see the enlarged eye-teeth foreshadowing the condition in apes, in the other, the small front teeth and the emphasis on molars which seems to characterise human origins. They look like miniature blueprints of things to come. The hint of a very ancient, separate origin of the human line certainly is there. Yet there are obvious and haunting resemblances between apes and men. In part they certainly reflect a common heritage; but an important part is also due to parallel evolution during those 30 million years (give or take 10 million) that apes and protomen have been distinct. This is certainly true for such important traits as the relatively lafge size (early Fayum prototypes were no larger than a cat), the lack of a tail (still present in Fayum apes), the tendency to an upright posture (only semi-erect in the apes) and the highly developed flexibility of the hand (still poorly developed some 15 million years ago)., Much remains to be filled in. But at least the real, historical evidence is now becoming available; and only in this way can the problem of man’s origin be solved.

Bjom Kurten is a professor at the University of Helsinki and author of the forthcoming book *' “Not From The Apes.” The article comes from the New York Times Special Feature Service, through N.Z.P.A.