The natural history of population : University of London Heath Clark Lectures 1937 delivered at the London School of Hygiene and Tropical Medicine / by Raymond Pearl.

  • Raymond Pearl
Date:
1939
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Licence: In copyright

Credit: The natural history of population : University of London Heath Clark Lectures 1937 delivered at the London School of Hygiene and Tropical Medicine / by Raymond Pearl. Source: Wellcome Collection.

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    other organisms may do or think about it. When extinction threatens, every resource is brought to bear to fend it off. Basically this is what underlies the struggle for existence. Out of it, associated with it, and because of it come great ranges of biological phenomena that have been departmen¬ talized for combined reasons of convenience and pedantry. These include such things as food-getting, metabolism, and nutrition, cellular and humoral defence mechanisms furnish¬ ing immunity and resistance to disease, protective shelter¬ seeking and building, natural selection, and in good part evolution itself. As a matter of observed fact, this survival urge is primal and deeply rooted. Whenever and wherever we see its fundamental selfishness apparently in abeyance or even much abated, and seemingly replaced by altruism or mutual aid , as it has been called, we may be fairly sure that one or the other of two things has happened. Either, as among the invertebrates (especially the social insects) and the lower vertebrates, the ‘mutual aid’ is not individually motivated but is a mechanistic group-consequence of caste differentiation and integration, with no more (and no less) of an altruistic element in it than there is in the cellular differentiation and integration in the embryonic develop¬ ment of the individual; or, as in man, and to some extent among his nearest relatives, complex psychological elements have been added to the picture in the course of evolution which may seem at times to overwhelm and obliterate the more primitive and deeply rooted biological urge. The most obvious of these added factors amounts really to a more enlightened self interest—that is to say, a belief that for the present, and until times get much worse, it will be likely to conduce more effectively to individual survival to play along with and help one’s neighbours in the crowd. This statement is, from the necessity of brevity, much too bald and apparently dogmatic in its form, and wants more explanatory elucidation and development than we can give it here. But it essentially conforms to at least a part of the reality. It is reasonable to suppose that the individual soldier ant is unaware of the fact that its activities and
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