A problem in human evolution.

  • Allen, Grant.
Date:
[1879]
Catalogue details

Licence: Public Domain Mark

Credit: A problem in human evolution. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    ersed habits of sitting and lying down which it necessarily mvo ves, - seems to me that he must have begun to lose the hair upon ns ack. But such a partial loss will not fully account for his presen ■cry hairless condition over the whole body (with trifling exceptions n the average of all sexes, races, and ages. For this farther am omplete denudation I think we must agree with Mr. Darwin m nvoking the aid of sexual selection, especially when we take m o onsideration the ornamental and regular character of the hairy djuncts which man still retains. In the first place, we have external reasons for believing that exual selection lias produced similar results elsewhere, acting upon t like basis of natural denudation. For among the mandrills and i0me other monkeys the naked callosities, originally produced, as is acre suggested, by physical friction, have been utilised for the dis- iplay of beautiful pigments ; and Mr. Bartlett informed Mr. Darwin Fat as the animals reach maturity the naked surfaces grow larger in comparison with the size of the body. M hen we look at great definiteness and strange colouring of these bare patches we can hardly doubt that they have been subjected to some such selective process. But if man once began to lose the hair over the whole of his back, shoulders, and haunches, as well as more partially upon his sides, legs, and arms, he would soon present an intermediate haif- hairy appearance which is certainly very ludicrous and shah 03 - looking. Why this middle stage should displease us, it might be rash to guess ; yet one may remember that as a rule throughout the mammalia a partially hairless body would be associated with mangi- ness, disease, and deformity. At any rate, it seems to be the fact that when animals once begin losing their hair, they go 011 to lose it altogether. One may well believe that among our evolving semi- human ancestors those individuals which had most completely divested themselves of hair, would be the most attractive to their mates, and these would also on the average be those which had most fully adopted the erect attitude with its accompanying alterations ot habit. Thus natural selection would go hand in hand with sexual selection (as I believe it always does), those anthropoids which most nearly approached the 3ret unrealised standard of humanity being most likely to select one another as mates, and their offspring being most likely to survive in the struggle for life with their less anthro- poid competitors.1 It does not seem probable, to me at least, that a naturally hairy species would entirely divest itself of its hair through sexual selection, especially as the first steps of such a pro- cess could hardly fail to render it a mongrel-looking and miserable (1) On the advantages -which man or his half-developed ancestor dciived from the erect or semi-erect position, see Darwin, Descent of Man, p. o<3.