Pick from the Past
Natural History, November-December 1933
Man500,000 Years From Now
|The use of our arms and legs, even though it be only for sport, will be vigorous. In this I agree with Aldous Huxley in whose brave new world man employs machines to his enhanced satisfaction but nevertheless enjoys the exercises of his body.|
It is conceivable, even inevitable, in the future society of which our man will be a part that the population will be mated as carefully as the animal breeder now controls his stock. To some extent this may interfere with the direction of human development, but it will not deflect the stream of evolution very far from its course. Finally, it must be understood that my predictions concern Europeans especially, although some of my prophecies may be applied with equal assurance to other stocks.
Let us begin this hasty preview by focusing our eyes on a distance of say 500,000 years. We might, of course, have taken 1,000,000 or even more years, but I prefer to be modest. On the other hand, some of my readers, no doubt, are slightly myopic and will have little interest in a world as remote as this. They will find it difficult to feel grand-paternal toward their great 16,666 grandchildren. But let them remember that even their own children may resemble themselves as little as their future descendants. And yet who would deny their interest in their offspring. But my real reason for not limiting our vision to 1,000 or 10,000 or even 50,000 years hence is that it would be rather difficult in the hasty glimpse, which are about to take, to find much in the way of interesting differences. For man does not change very rapidly, and we must allow him sufficient time to undergo a few modifications.
As a matter of fact when we look back over mans dilatory path we are somewhat amazed that although, measured in time, long eras have passed since the upper Paleolithic Age, yet in the way of modern improvements the gain seems negligible indeed. We must perforce delve even deeper into the human pastto the period of Neanderthal Man and even earlier to the days of Pithecanthropusbefore sharp differences from Homo sapiens appear to the unprofessional eye.
It is rather difficult to determine whether the rate of mans evolution has been slower or faster than that of other creatures. Certainly in contrast with some of the lowly molluscs, such as the brachiopods for example, man has been a veritable greyhound, nor has he, compared with the horse, shown any tendency to lag. We must conclude that mans capabilities for advancement are excellent, but that evolution is a slow process requiring great stretches of time to manifest itself. If, therefore, my picture of the average man of 501,933 A.D. does not conform to your esthetics, you can at least take comfort in the thought that the man of 6933 A.D. will be but little different from what he is today, and for most of us that is far enough ahead to worry about.
The Distinctive Traits of Man
The most striking changes which have occurred in the evolution of man from a four-footed (or four-handed, if you prefer) primate to his present proud estate are the marked increase of the brain and the assumption of an upright posture. Upon these developments a numerous series of subsidiary changes are dependent. But these two, upright posture and highly evolved brain, more than anything else distinguish man anatomically from his anthropoid predecessors. And of the two I am inclined, perhaps cynically, to hold that the upright posture is the more distinctive. From that remote day in the past when our ancestral anthropoid stock left off using its forelimbs in locomotion and stood up on its own hind legs the upright posture has remained essentially the same. Although the structure of those enterprising primates had been, to some degree, prepared for such an upward step by a long arboreal tutelage, nevertheless one can readily apprehend the repercussions which that event would have on numerous skeletal traits and internal organs, and one can appreciate the pains of adjustment which would follow. For this new mode of progression made it necessary among other rearrangements, for the foot to develop into a more firmly knit and resistant mechanism, for the pelvis to take on an increased weight-bearing function, for the thorax to become flattened and for the internal organs to be suspended in the longitudinal axis of the body. The point is that although all sorts of accommodations, some of which are still imperfect, were slowly being made in the structure of these early bipeds, the very stimulus to these gradual alterations remained unchanged. In other words, man having achieved this step, did not proceed further along that road for the simple reason that he couldnt. Once the upright posture is attained one cant go on becoming more and more upright.
The brain, however, underwent no such circumscribed development. It merely expanded slowly. And while the upright posture has remained fixed, the brain, on the contrary, has continued to increase in size and complexity. For this reason the brain and its enclosing skull are areas where the most significant changes have taken place during the more strictly human history of man.
A Larger Brain
I can venture, therefore, with some confidence to predict that man in 500,000 years will continue to be an upright creature, and with some hesitation that his brain will be larger. The reason for my slight hesitancy with regard to the expansion of the brain in the near future (for 500,000 years is but a few days in mans phylogenetic existence) is that there are some indications that the quality of the brain may improve without a concomitant increase in size. Moreover, Keith has shown that among the Bushmen, for example, the cranial capacity of their ancestors was much greater than is their own. Furthermore, Rhodesian man and some of the Neanderthal burlies of 50,000 years ago had skulls the size of which were equal to if not greater than our own. But in general the tendency from Sinanthropus and Pithecanthropus to modern man has been for the brain to expand. Actually the cranial capacity of Pithecanthropus was about 900 cubic centimeters (roughly 1000 cc. in Sinanthropus), appreciably larger than the average for gorillas, 500 cc., and than that for chimpanzees, 400 cc., but much smaller than we find commonly among Europeans, 1450 cc. If we accept the recent estimates that Pithecanthropus lived at the end of the Pliocene or the beginning of the Pleistocene, a matter of 1,000,000 years ago, we might, by the assumption of a constant rate of increase and with the aid of simple arithmetical processes, arrive at a capacity of 1725 cc. for our future man 500,000 years hence. But this need not call up a picture of a balloon-headed individual. There are men to be met without special comment on the streets today whose skull capacity reaches and even exceeds this figure.
Changes in Skull Shape
Professor Arthur Thomson investigated some years ago the effect on the skull of an increased capacity. He found by a simple experiment that if the base of the cranium were kept constant, the cranial vault tended to become rounder as its capacity expanded. The mechanics of this experiment have been amply supported by a number of statistical studies yielding high correlations between head form and cranial capacity.
|We can, therefore, assume that our hypothetical homo futurus will have not only a larger head or brain case but a rounder one as well.|
Other Changes in the Skull
Pari passu with the expansion of the skull, which I anticipate will continue into the future, there has been a refinement of the modeling of the skull. The angular and crude primitive cranium has gradually been converted into a smoother and more gracile one. I shant go into all the ways in which this has taken place. That would require a volume. But an important change readily noticeable to the average observer has been the reduction of the prominent bony ridges over the eyes, which in anthropoids and fossil men resemble a heavy bar. At present the female of the human species tends to have a brow that is more or less vertical and smooth above the eyes; whereas in the male there is a moderate swelling above the root of the nose in the region called glabella. To either side of this glabellar area vestigial ridges of bone still persist in the modern male. It is a well marked sex difference and is clearly apparent. With the aid of our evolutionary series we notice that there has been a consistent expansion of the frontal region and a smoothing of the brow as we advance from the primates to modern man. In this respect the female has always been in advance of the male and has pointed the direction in which he has traveled. The ladies may take pleasure in contemplating that it will have taken the males 500,000 years to attain the smoothness of brow which they now possess. As for the females themselves, if a sex difference in the frontal region of the skull is to persist, they will develop infantile browsslightly bulbous.
It was the renowned Metchnikoff, I believe, who considered the digestive organs a grossly over-developed system in the human economy. Certainly, many of his less accomplished successors predict the future man with a very reduced digestive apparatus, sufficient only to absorb
|The ladies may take pleasure in contemplating that it will have taken the males 500,000 years to attain the smoothness of brow which they now possess.|
But even though our digestive system remains intact, one adjunct to it is undergoing modifications and will continue to do so. This is the dentition. No vertebrate is afflicted with such extensive dental decay as is man. Hardly a child among us reaches puberty without some decay developing, few adolescents attain maturity without loss of teeth from caries, and a large number of adults only have teeth at all by the constant vigilance of the dentists.
Unfortunately decay, or caries, is not the only evidence of a serious readjustment going on in our dentition. This is seen also in the frequency with which our teeth are malerupted. Twisted teeth, impacted molars, faulty alignments and malocclusions are too common to be lightly dismissed. They indicate a deep-seated force at work which is generally affecting the population. Indeed, so numerous are the children suffering from these maleruptions that there has grown into being a branch of dentistry, orthodontia, devoted expressly to the correction of these dental faults.
But this is not the whole story of the degeneration of the human dentition. In still other ways it manifests itself. I shall mention only two more. One is the increasing suppression of the third molars or wisdom teeth. Not only is the age at which is normally erupts, 18 to 20, being pushed back later and later in life, but in many people they are absent in whole or in part. The second is the constriction of the jaws. It is obvious that the crowding of the teeth and the constriction of the jaws may be associated, but not always is this the case.
One cannot help being convinced that all this evidence is symptomatic of a fundamental process which may in time be responsible for considerable alterations to our dental equipment. I do not propose to enunciate a dogmatic generalization to account for this situation. Controversies on the nature and cure of dental decay have flourished for generations among those interested in teeth. Decay has been attributed to hyperacidity, to endocrine dysfunction and to diet, among other factors. No doubt the situation is a complex one and the superficial causes may be as varied as the manifestations they produce. But one cannot but be impressed by the fact that the dentition is an area of weakness. My guess is that the teeth are, to a large extent, losing their function and consequently becoming less vigorous and resistant. In other words, they are readjusting themselves to the changed demands upon them. This in itself reduces them to a state of relative non-resistance which makes them especially prone to secondary attacksendocrine dysfunction, faulty diet and hyperacidity. In their weakened state they are unable to withstand attacks that in lower forms are easily resisted. Perhaps I can make my idea clearer by comparing them to an army which, kept in constant and full use of its powers, is able to put up a good defense against its enemies. But suppose such an army were not systematically employed but took its ease in comfortable barracks and never exercised its warlike functions. Then an attack would decimate it. So the teeth have lost their resistance and so they capitulate to the onslaughts of their enemies.
Fewer and Smaller Teeth
We may see this perhaps more clearly by examining the toughened teeth of anthropoids and early man. Of course, decay is not completely unknown even among these creatures, but it is rare. The third molars do in most cases erupt complete and sound, and the position and alignment of the teeth in their serried arches would delight the heart of an orthodontist, accustomed to the misshapen jaws of his patients. Even among present-day Eskimo who alone among living people make full use of their teeth the same beauty of dentition is present. From the primates to modern man
Since it is improbable that we shall return to the tough, resistant food on which our predecessors thrived, the chances are that our dentitions will continue to deteriorate.
We are now in the position to predict the future condition of the teeth of our gradually emerging man. Since it is improbable that we shall return to the tough, resistant food on which our predecessors thrived, the chances are that our dentitions will continue to deteriorate. Future man will have lost his third molars, many of them will also show reduced or absent lateral incisors. The jaws will be smaller and what teeth are present will be diminished in size.
This predicted diminution of the size of the jaws and the teeth goes hand in hand with a reduction in the muscle masses which control the masticatory movements of the mandible. Since the cheek bones and their lateral arches serve to enclose these muscles and to take up the pressure created in chewing, it is apparent with a less vigorous mastication and a decrease in the muscle mass that the facial parts will likewise undergo a modification. Homo futurus will have, therefore, in addition to his other characteristics, a relatively smaller face.
I mentioned previously that the skull base has shown a marked decrease in modern man. There is a good architectural reason for this. The base of the skull is intimately associated with the face which is linked to it. In fact, it might better be said that the base of the skull is determined by the needs of the facial structure for attachment. Since it is well known that the face has gradually become reduced in length and in horizontal projection, it follows that its field of attachment on the skull base has shown a correlated reduction. Other things being equal, a shorter cranial base means a rounder head. But the decreasing length of the skull base and its facial attachment has another significance here. It calls attention to the marked recession of the face which is so definite in mans phylogeny. In the primates the jaws project like a muzzle and are labelled prognathic. But in modern Europeans the profile of the jaws has receded to a vertical line dropped from the root of the nose, a condition known as orthognathism. From what has been prophesied already for the man of the future it is clear that this recession will be emphasized to an even greater degree.
Let us turn to another attribute of our average man of 500,000 years from now. This future being will be taller than we are. My reasons for this belief are in reality simple. It is, in the first place, well known that in many forms of evolving species there is a definite increase of size during the course of their evolution. The giant reptilian forms of the Mesozoicthe dinosaurs, the brontosaurs and their relativesall began as small forms and gradually put on weight. One of these ponderous creatures might well have looked back to its phylogenetic youth and sung with sadness:
Fading is the taper waist,
Shapeless grows the shapely limb,
And although severely laced,
Spreading is the figure trim!
Stouter than I used to be,
Still more corpulent grow I.
There will be too much of me
In the coming bye and bye
There will be too much of me
In the coming bye and bye.
Indeed this phenomenon is a common one. We see it again in the phylogeny of the horse, the camel, and in various other mammals. In the primates, too, the sequence runs from the small lemuroid creatures to the hefty gorillas. Now, in man it has likewise been observed that the stature of early man is often near the upper limits of pygmy stature whereas we overtop them considerably. Projecting this trend into the future we must anticipate an increasingly taller and bigger man. But there is other evidence to support this prophecy.
|In many forms of evolving species there is a definite increase of size during the course of their evolution. The giant reptilian forms of the Mesozoic the dinosaurs, the brontosaurs and their relativesall began as small forms and gradually put on weight.|
We now have the major aspectsthe high lightsof the portrait of our future man. At any rate these are all I have space to expand upon. I shall now turn to a few of the details which give character and individuality to our drawing.
If any one of my readers happens to be a chiropodist who has had abundant opportunity to examine minutely and professionally a large number of feet, he will bear me out that the little toe is frequently very little indeed. Sometimes this fifth toe even lacks a toe nail, or it may have only the merest suggestion of one like a tiny clawnot a flat nail. Unfortunately in this respect I cannot compare the present state of affairs with the condition of the little toe in early man because his toes are not preserved for our inspection. But we can study the toes of the anthropoid feet nearest mansthe gorillas. Here we find a well developed little toe with a complete nail. From this we deduce that mans little toe has become progressively smaller and more useless.
The Loss of the Fifth Toe
An analysis of the mechanics of the foot reveals why this is so. In the primitive primate foot the line of leverage in walking passes through the middle toe, which symbolized its primacy over the other toes by its greater length. In the course of primate evolution the line of leverage shifted to a position midway between the big and the second toes as a result of adaptation. In man we find that the line of leverage has remained in this position or even moved over entirely to the big toe. As a result of this greater weight bearing and mechanical functioning the big toe has grown to the largest of all the toes with a progressive decrease in size and function as one moves to the little toe. The increasing loss of function in the little toe is revealed by the fact, which was mentioned above, that in a large number of people it has degenerated to a tiny digit often without a nail or only the merest vestige of one. This suggests the probability of its future disappearance. But since nature is slow I dare go only so far as to predict that the little toe of our future man will be even littler and that in many it will perhaps be simply a suggestion of a digit. This loss of toes, however, need not surprise us, for it is a phenomenon well known in the evolution of a number of common mammals, such as the horse, cow, camel, pig, etc.
We are now coming rapidly to an end of this portraiture, but I wish to complete the picture with a few words on the hair of our future man. It is well known, or more precisely,
|This loss of toes, however, need not surprise us, for it is a phenomenon well known in the evolution of a number of common mammals, such as the horse, cow, camel, pig, etc.|
Finally, we shall give our future man less body hair than he now possesses. Man varies widely in the amount of body hair with which he is covered. But among all groups he is relatively glabrous, or hairless, when compared with the anthropoids. Indeed, it is evident that in the course of human evolution the pelt has constantly diminished. This process of depilation has advanced farther in some races than in others. The Mongoloid people, for example,
I hazard the guess that with advance in civilization the incidence of baldness will increase, and that in the future of 500,000 years from now it will not only appear earlier but more extensively.
To sum up our prophecies on the future man we may impressionistically describe him as taller than we, with a more capacious and rounder head, fronted by a more vertical and smoother brow. His face will be smaller and more recessive in profile. The teeth in his jaws will be reduced in number and will also be smaller in size. In particular the third molars, but also in some cases, the lateral incisors will be absent. Caries or dental decay will continue to be a serious problem requiring constant supervision to keep in check. Some representatives of this future race will walk on four-toed feet and many will in early adulthood have become bald. The body hair will be less abundant, perhaps reaching the condition of hairlessness found in Chinese and Negroes.
These, then, are some of the characteristics which I predict for the man of the future. But in addition to these differences from ourselves, there will be many similarities, so many in fact that you would have little trouble in recognizing him as a fellow-member of the same genus. But were you miraculously preserved to that far distant future, I am afraid that you would need to seek among the phylogenetic laggards and the primitive people for somebody exactly like the folks back home.