The science of life : fully illustrated in tone and line and including many diagrams

PECULIARITIES OF THE SPECIES HOMO SAPIENS

and to discuss the claims of this or that restricted region to be “ the cradle of mankind.” They imagine, one supposes, a particular couple of some species of subman suddenly discovering themselves “ different and starting out upon a new way of life. ‘* Let’s found a new species, my dear,”’ is the note of it. But the reader will have read this work but carelessly if he is still under the delusion that new species appear in any such fashion.

As we have spread modern concepts before him, he will have realized how species constantly produce mutations of type which, if they give advantages leading to their natural selection, may become prevalent in that species, locally or extensively. Most of these mutations are very slight in their effects. They turn up here and

kill, to mix, to learn from each other by imitation and precept, and start yet further variations through genetic discord. ; We cannot say that the primordial varieties and species of Homo were forest or bush inhabitants or dwellers on the border of steppe country. Much more probably they were all those and also other things. The early skeletons of true men found in the Grimaldi caves belong to two types, the Cro Magnon type and the Grimaldi type, as widely different as the Red Indian is from the Negro to-day. But certain characteristics the species of Homo already had in common. ‘They were, for example, less highly specialized for the forest life and they were already far more gregarious than the great apes. The great apes are all rather

there over the range of the species ; one individual appears with a change in _colour-pattern; another with a difference elsewhere in its body ; and because of the constant mixture by interbreeding of the population these mutations are brought together into more or less favourable combinations. Locally or extensively one combination may prevail altogether, and if it prevails locally and is cut off geographically, or produces in association with its other characteristics some change in its reproductive quality, it may become incapable of interbreeding with the original type and so become in the fullest sense a mew species. All species present the phenomenon of local variation and some, like the domestic dogs, present extraordinary varieties of type which yet retain a common capacity for fertile offspring. It is possible that the Hominide, whose rare infrequent fossils are now coming to light in this or that region of the old world, and of whom we are continually discovering fresh types, may have been, as are the domestic dogs, interbreeding varieties. It is pure guesswork whether Homo neanderthalensis in any region interbred or did not interbreed with Homo Sapiens. Just as there never seems to have been a single sort of domestic dog from which all other sorts sprang, but an advancing interplay of various sorts, so quite possibly there was never a single primordial sort of Homo sapiens. The race varied widely locally, strongly marked types appeared under special conditions, and then with geographical changes other human types came flooding in, still capable of fertile interbreeding, to

Fig. 336. A new link in the chain of human descent.

The brain-case of the sub-man, Sinanthropus, found in China by Mr. W. C. Pei, of the Chinese Geological Survey. brow-ridges over the eyes are seen at the right. of the Ape-man, larger brain. n

1929. (Courtesy of Prof. Davidson Black, of Peking.)

The prominent This skull is like that Pithecanthropus, except that it housed a distinctly This important discovery was only made in December,

solitary creatures. They live in little family groups, which are typically dominated by an old male ; they are jealous of intruders upon their territory and mix freely only in their own group. Consequently, comparatively rare though these creatures are, they display considerable local variation. The West Coast gorilla is quite distinct from the mountain gorilla of Central Africa, not only in physical characters, but in temperament. Several varieties of orang-utang are known, some of which should probably be classed as distinct species. As we have previously mentioned, the old males of at least one variety have strange fleshy frills round their faces. And the chimpanzees from different regions of Africa are of markedly different types. Although chimpanzee coat-colour only ranges between brown, grey, and black, the

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