June, 1931 



EVOLUTION 



Page fifteen 



What Is Man Becoming? 



By ALES HRDLICKA 

 Curator of Anthropology, U. S. National Museum 



'^^To SUBJECT has occupied attention more than the future 

 •*- ^ of the individual after death; but the amount of thought 

 given to the terrestrial future of man has been astonishingly 

 small. Even now, thoroughly conscious as scientific workers are 

 of human evolution in the past, they seldom attempt to pic- 

 ture what may happen with man during the' endless stretches 

 of time ahead of him. 



Had we a perfect knowledge of the human past, our whole 

 mental attitude towards the human problem would be altered. 

 We should much more fully understand ourselves, could much 

 better appreciate and weigh the changes in man now going on, 

 and could to a considerable extent deduce validly at least the 

 nearer future of the human species. 



The essentials of the knowledge of man's past are: 



Man, in origin, is not apart from but belongs to the rest of 

 the living world. 



Man has developed, in all probability gradually, from the 

 nearest subhuman forms, and under the exciting influence of 

 environmental conditions. He then progressed gradually, 

 though doubtless not regularly or at the same rate, towards 

 his present status. During this progress he diSFerentiated into 

 numerous types and races, the less successful of which have 

 become extinct. He is still substantially attuned to Nature, 

 though the relation is weakened through his artificialities. 



Up to the end of the last main glaciation, man progressed 

 evidently but very slowly in numbers. In general he did seem- 

 ingly but slightly better than to sustain himself. His spread 

 was slow and sparse. But after the main part of the last gla- 

 cial invasion he begins to multiply much more effectively and 

 as his numbers increase there follows gradually a spread all 

 over the habitable earth, with an accentuated differentiation of 

 types and races. The latter proceeded all, according to the best 

 evidence, from but one human species, and those now living 

 date all from the later, post-glacial, parts of human prehistory; 

 earlier strains, such as doubtless there were, can no more be 

 traced among living men. 



The main phenomena of human differentiation or "evolu- 

 tion" throughout the past, are on one hand a progressive men- 

 tality, on the other hand a progressive physical adaptation and 

 eventual refinement. It is a wonderful and, in general, sus- 

 tained progress from a more-or-less ape-like precursor to the 

 highest type of man and woman of today. 



When we impersonally observe the present, it is seen, not- 

 withstanding its great complexities, to be merely a developing 

 continuation of the past. Man is still, it appears, as plastic in 

 body and mind as he ever was, probably even more so; he is 

 4^ still struggling with environment, though controlling it more 

 and more every day; and he still changes. 



He lives longer and better. He suffers less physically. Elimin- 

 ation of the less fit has largely changed to elimination of the 

 unfit only. Less mother's and child's hard labor, more and bet- 

 ter food, with exercise, sport and personal hygiene, are bring- 

 ing about an increase in stature of civilized man, while less use 



•Proceedings of American Phylosophical Society 



of the jaws and muscles of mastication is reducing the teeth, 

 the jaws, the breadth, protrusion and massiveness of the face. 

 The head in general among the cultured is becoming slightly 

 broader and larger, the skull and facial bones thinner, the phy- 

 siognomy more lively and expressive. 



The features, the hands, the feet, are becoming more re- 

 fined, and general beauty is on the increase, in both men and 

 women. The sensory organs and centers, particularly those of 

 sight, hearing and taste, are evidently growing more effective 

 as well as more resistant. And there is unquestionable advance 

 in civilized man of mental effectiveness and mental endow- 

 ments. Records in endurance and in accomplishments are ever 

 being surpassed, and in modern commerce, industry, finance, 

 science, applied arts, bring to light mental giant after giant. 



Those and other progressive changes in the cultured man 

 of the present are resulting, it is true, in various weakenings 

 and consequent disorders. The hair, especially in the men, is 

 being lost prematurely; the teeth are weakened in resistance, 

 there are troubles of eruption, and some of the dental units 

 tend to disappear. The facial changes, while favoring a greater 

 variety and higher range of the voice, lead often to disturbing 

 irregularities of the nasal structures and palate. The weaken- 

 ings through less use of the feet and other organs (appendix, 

 muscles, etc.) result in difEculties, even dangers. Great mental 

 application favors digestive and other disorders; etc. But all 

 these disadvantages are being checked by new adaptations and 

 have but a moderate effect of retardation on the general evo- 

 lutionary progress of civilized man. 



Such, in high lights, was man's past and such is his present, 

 in evolution. The important problem before us is what, on the 

 basis of what preceded and what is now observable, may with 

 approximate safety be expected for the future. 



In general man's past and present permit the statement that 

 he is not yet perceptibly near the end of his evolution, and the 

 prediction that, according to all indications, he will for long 

 yet keep on progressing in adaptation, refinement and differ- 

 entiation. But this applies only to the main stream of human- 

 ity, the civilized man. The rest will be more or less brought 

 along, or left behind. 



The progress of the advancing parts of the race may be 

 foreseen to be essentially towards ever greater mental efficiency 

 and potentiality. The further mental developments may be 

 expected to be attended by an additional increase in brain size; 

 but this gross increase will be of but moderate proportions. 

 The main changes will be in the internal organization of the 

 brains, in greater blood-supply, greater general effectiveness. 



The skull will in all probability be still thirmer than it is 

 today. And the skull may on the whole be expected to grow 

 fuller laterally and also antero-posteriorly, due to developments 

 in the directions of least resistance. The hair of the head, the 

 indications are, will probably be further weakened. The sta- 

 ture promises generally to be even somewhat higher than to- 

 day among the best nourished and least repressed groups. 



The face will, it may be expected, proceed slowly in refine- 

 ment and handsomeness and character. This partly through in- 



