Part 22 (1/2)

[Ill.u.s.tration: _Photo: New York Zoological Park._

THE ORANG HAS A HIGH ROUNDED SKULL AND A LONG FACE]

[Ill.u.s.tration: _Photo: British Museum (Natural History)._

COMPARISONS OF THE SKELETONS OF HORSE AND MAN

Bone for bone, the two skeletons are like one another, though man is a biped and the horse a quadruped. The backbone in man is mainly vertical; the backbone in the horse is horizontal except in the neck and the tail.

Man's skull is mainly in a line with the backbone; the horse's at an angle to it. Both man and horse have seven neck vertebrae. Man has five digits on each limb; the horse has only one digit well developed on each limb.]

It may be urged that we are attaching too much importance to the arboreal apprentices.h.i.+p, since many tree-loving animals remain to-day very innocent creatures. To this reasonable objection there are two answers, first that in its many acquisitions the arboreal evolution of the _humanoid_ precursors of man prepared the way for the survival of a _human_ type marked by a great step in brain-development; and second that the pa.s.sage from the humanoid to the human was probably a.s.sociated with _a return to mother earth_.

According to Professor Lull, to whose fine textbook, _Organic Evolution_ (1917), we are much indebted, ”climatic conditions in Asia in the Miocene or early Pliocene were such as to compel the descent of the pre-human ancestor from the trees, a step which was absolutely essential to further human development.” Continental elevation and consequent aridity led to a dwindling of the forests, and forced the ape-man to come to earth. ”And at the last arose the man.”

According to Lull, the descent from the trees was a.s.sociated with the a.s.sumption of a more erect posture, with increased liberation and plasticity of the hand, with becoming a hunter, with experiments towards clothing and shelter, with an exploring habit, and with the beginning of communal life.

It is a plausible view that the transition from the humanoid to the human was effected by a discontinuous variation of considerable magnitude, what is nowadays called a _mutation_, and that it had mainly to do with the brain and the vocal organs. But given the gains of the arboreal apprentices.h.i.+p, the stimulus of an enforced descent to terra firma, and an evolving brain and voice, we can recognise accessory factors which helped success to succeed. Perhaps the absence of great physical strength prompted reliance on wits; the prolongation of infancy would help to educate the parents in gentleness; the strengthening of the feeling of kins.h.i.+p would favour the evolution of family and social life--of which there are many antic.i.p.ations at lower levels. There is much truth in the saying: ”Man did not make society, society made man.”

A continuation of the story will deal with the emergence of the primitive types of man and the gradual ascent of the modern species.

-- 4

Tentative Men

So far the story has been that of the sifting out of a humanoid stock and of the transition to human kind, from the ancestors of apes and men to the man-ape, and from the man-ape to man. It looks as if the sifting-out process had proceeded further, for there were several human branches that did not lead on to the modern type of man.

1. The first of these is represented by the scanty fossil remains known as _Pithecanthropus erectus_, found in Java in fossiliferous beds which date from the end of the Pliocene or the beginning of the Pleistocene era. Perhaps this means half a million years ago, and the remains occurred along with those of some mammals which are now extinct.

Unfortunately the remains of Pithecanthropus the Erect consisted only of a skull-cap, a thigh-bone, and two back teeth, so it is not surprising that experts should differ considerably in their interpretation of what was found. Some have regarded the remains as those of a large gibbon, others as those of a pre-human ape-man, and others as those of a primitive man off the main line of ascent. According to Sir Arthur Keith, Pithecanthropus was ”a being human in stature, human in gait, human in all its parts, save its brain.” The thigh-bone indicates a height of about 5 feet 7 inches, one inch less than the average height of the men of to-day. The skull-cap indicates a low, flat forehead, beetling brows, and a capacity about two-thirds of the modern size. The remains were found by Dubois, in 1894, in Trinil in Central Java.

2. The next offshoot is represented by the Heidelberg man (_h.o.m.o heidelbergensis_), discovered near Heidelberg in 1907 by Dr.

Schoetensack. But the remains consisted only of a lower jaw and its teeth. Along with this relic were bones of various mammals, including some long since extinct in Europe, such as elephant, rhinoceros, bison, and lion. The circ.u.mstances indicate an age of perhaps 300,000 years ago. There were also very crude flint implements (or eoliths). But the teeth are human teeth, and the jaw seems transitional between that of an anthropoid ape and that of man. Thus there was no chin. According to most authorities the lower jaw from the Heidelberg sand-pit must be regarded as a relic of a primitive type off the main line of human ascent.

[Ill.u.s.tration: A RECONSTRUCTION OF THE JAVA MAN

(_Pithecanthropus erectus._)]

3. It was in all probability in the Pliocene that there took origin the Neanderthal species of man, _h.o.m.o neanderthalensis_, first known from remains found in 1856 in the Neanderthal ravine near Dusseldorf.

According to some authorities Neanderthal man was living in Europe a quarter of a million years ago. Other specimens were afterwards found elsewhere, e.g. in Belgium (”the men of Spy”), in France, in Croatia, and at Gibraltar, so that a good deal is known of Neanderthal man. He was a loose-limbed fellow, short of stature and of slouching gait, but a skilful artificer, fas.h.i.+oning beautifully worked flints with a characteristic style. He used fire; he buried his dead reverently and furnished them with an outfit for a long journey; and he had a big brain. But he had great beetling, ape-like eyebrow ridges and ma.s.sive jaws, and he showed ”simian characters swarming in the details of his structure.” In most of the points in which he differs from modern man he approaches the anthropoid apes, and he must be regarded as a low type of man off the main line. Huxley regarded the Neanderthal man as a low form of the modern type, but expert opinion seems to agree rather with the view maintained in 1864 by Professor William King of Galway, that the Neanderthal man represents a distinct species off the main line of ascent. He disappeared with apparent suddenness (like some aboriginal races to-day) about the end of the Fourth Great Ice Age; but there is evidence that before he ceased to be there had emerged a successor rather than a descendant--the modern man.

4. Another offshoot from the main line is probably represented by the Piltdown man, found in Suss.e.x in 1912. The remains consisted of the walls of the skull, which indicate a large brain, and a high forehead without the beetling eyebrows of the Neanderthal man and Pithecanthropus. The ”find” included a tooth and part of a lower jaw, but these perhaps belong to some ape, for they are very discrepant. The Piltdown skull represents the most ancient human remains as yet found in Britain, and Dr. Smith Woodward's establishment of a separate genus Eoanthropus expresses his conviction that the Piltdown man was off the line of the evolution of the modern type. If the tooth and piece of lower jaw belong to the Piltdown skull, then there was a remarkable combination of ape-like and human characters. As regards the brain, _inferred_ from the skull-walls, Sir Arthur Keith says:

All the essential features of the brain of modern man are to be seen in the brain cast. There are some which must be regarded as primitive. There can be no doubt that it is built on exactly the same lines as our modern brains. A few minor alterations would make it in all respects a modern brain.... Although our knowledge of the human brain is limited--there are large areas to which we can a.s.sign no definite function--we may rest a.s.sured that a brain which was shaped in a mould so similar to our own was one which responded to the outside world as ours does. Piltdown man saw, heard, felt, thought, and dreamt much as we do still.

And this was 150,000 years ago at a modern estimate, and some would say half a million.

There is neither agreement nor certainty as to the antiquity of man, except that the modern type was distinguishable from its collaterals hundreds of thousands of years ago. The general impression left is very grand. In remote antiquity the Primate stem diverged from the other orders of mammals; it sent forth its tentative branches, and the result was a tangle of monkeys; ages pa.s.sed and the monkeys were left behind, while the main stem, still probing its way, gave off the Anthropoid apes, both small and large. But they too were left behind, and the main line gave off other experiments--indications of which we know in Java, at Heidelberg, in the Neanderthal, and at Piltdown. None of these lasted or was made perfect. They represent _tentative_ men who had their day and ceased to be, our predecessors rather than our ancestors. Still, the main stem goes on evolving, and who will be bold enough to say what fruit it has yet to bear!

[Ill.u.s.tration: _After a model by J. H. McGregor._

PROFILE VIEW OF THE HEAD OF PITHECANTHROPUS, THE JAVA APE-MAN--AN EARLY OFFSHOOT FROM THE MAIN LINE OF MAN'S ASCENT