Natural selection in human populations : the measurement of ongoing genetic evolution in contemporary societies / edited Carl Jay Bajema.

Date:
[1971]
Catalogue details

Licence: Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

Credit: Natural selection in human populations : the measurement of ongoing genetic evolution in contemporary societies / edited Carl Jay Bajema. Source: Wellcome Collection.

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    Man and Natural Selection 5 evolution, which is the evolution of culture. Culture is a tremendously potent instru¬ ment for adaption to the environment. A very large part of the evolutionary progress, both biologically and culturally, has come from adversity. Life faces environments which are more often niggardly than bountiful, more frequently inimical than benign. For life to endure, it must develop defences and adaptions. Biological adaptation oc¬ curs through natural selection; new genes arise through mutation, sexual recombina¬ tion creates new combinations of genes, and natural selection acts to multiply the successful genetic endowments and to reduce the frequencies of the unsuccessful ones. In man and in man alone, adaptation may occur also through alteration of cul¬ ture. Many species of mammals have become adapted to cold climates by growing warm fur; man alone has achieved the same end by donning fur coats. Birds have mastered the air by becoming flying machines; man has conquered the air by build¬ ing flying machines. Biological and cultural evolutions of man are not independent; they are interde¬ pendent. The superorganic has an organic basis. Formation and maintenance of cul¬ ture presuppose a human genotype. Even the most clever ape cannot learn human culture. Some writers have jumped to the conclusion that the genetic development of the human species was completed before culture appeared, and that the evolution of culture has replaced biological evolution. This is not true. The two evolutions go to¬ gether, interacting and usually mutually reinforcing each other. There is feedback between genetics and culture. Culture is an adaptive mechanism supplemental to, but not incompatible with, biological adaptation. To be sure, adaptation by culture proved to be more efficacious, and, before all else, more rapid than adaptation by genes. This is why the emergence of the genetic basis of culture was the master stroke of the biological evolution of the human species. The genetic basis of culture should be improved or at least maintained. It should not be allowed to deteriorate. Natural Selection, Struggle, and Fitness Man has not only evolved; for better or for worse, he is also evolving. Is he to become a superman or a demigod? Or will the fate in store for him be like that of so many successful species of the past, which eventually declined and became ex¬ tinct? Long-term prophecies do not expose the prophets to the risk of being proved wrong too soon. I nevertheless do not wish to indulge here in prophecies or in de¬ signing utopias. I wish rather to investigate some of the evolutionary forces current¬ ly at work in the human species. According to the theory set forth by Darwin and Wallace more than a century ago, adaptation occurs in biological evolution by way of the process of natural se¬ lection. Does natural selection operate in modern mankind? This has to be an¬ swered obviously in the negative, if by natural you mean a world uninhabited and uninfluenced by man. But it is here that we must proceed with the greatest