Francis Galton: Pioneer of Heredity and Biometry

5. Four Evolutionary Problems

147 5 Four Evolutionary Problems In considering the Origin of Species, it is quite conceivable that a naturalist ... might come to the conclusion that each species had not been independently created, but had descended, like varieties, from other species. Nevertheless, such a conclusion, even if well founded, would be unsatisfactory , until it could be shown how the innumerable species inhabiting this world have been modified, so as to acquire that perfection of structure and coadaptation which most justly excites our admiration.... I am convinced that Natural Selection has been the main but not exclusive means of modification. Darwin, The Origin of Species Galton was not a naturalist, but he was stimulated by The Origin of Species to apply evolutionary thinking to several problems related to his primary interest in human biology and heredity. In this chapter we discuss four specific evolutionary questions that attracted his attention. The first two, the domestication of animals and the evolution of gregariousness , arose from his observations in Southern Africa; the third, the inheritance of human fertility and the consequent danger of marrying heiresses, arose out of data on the extinction of peerages which he gathered during his work on Hereditary Genius; the fourth, the evolution of sex, is discussed in his 1875 paper “A theory of heredity” and in later unpublished manuscripts. The Domestication of Animals The neolithic revolution about ten thousand years ago saw the change from a hunter-gatherer to an agricultural way of life, involving the domestication of animals and plants. Galton read a paper on “The first steps towards the domestication of animals” to the British Association in 148 Francis Galton 1864; it was published in full next year (Galton 1865b), and reprinted with minor changes in Inquiries into Human Faculty in 1883. With some changes of wording, this paper still provides a comprehensive summary of what is known about the subject today (Clutton-Brock 1999). He started from the observation that nearly all domestic animals were first reclaimed from wildness in prehistoric times; men of modern times had only been able to improve the races of animals that they had received from their forefathers in an already domesticated condition. He put forward the explanation that every animal, of any pretensions, has had numerous opportunities of becoming domesticated, since savages are fond of keeping them as pets, or as sacred animals, or in menageries. But these opportunities have only rarely led to any result since no animal is fitted for domestication unless it fulfills certain stringent conditions. Thus only a few species are capable of domestication, all of which were domesticated long ago. He listed six conditions needed for the domestication of a wild species of animal: 1. It should be hardy, and able to shift for itself and to thrive, although neglected; if it wanted much care, it would not be worth its keep. As evidence of the hardiness of domestic animals, he cited the rapidity with which they establish themselves in new lands: “The goats and hogs left on islands by the earlier navigators throve excellently on the whole” (1865b, 131). 2. It should have an inborn liking of man. He noted that attachments and aversions between different species occurred in nature, and that animals were only likely to be domesticated which had a mutual attachment with man: “Two herds of animals would hardly intermingle, unless their respective languages of action and of voice were mutually intelligible . The animal which above all others is a companion to man is the dog, and we observe how readily their proceedings are intelligible to each other.… A man irritates a dog by an ordinary laugh, he frightens him by an angry look, or he calms him by a kindly bearing; but he has less spontaneous hold over an ox or a sheep. He must study their ways and tutor his behaviour before he can either understand the feelings of those animals or make his own intelligible to them. He has no natural power at all over many other creatures. Who, for instance, ever succeeded in frowning away a mosquito, or in pacifying an angry wasp by a smile?” (133). 3. It should be comfort loving and attracted to human habitations. For example, antelope were not suitable for domestication because they were Four Evolutionary Problems 149 adapted to flee from fast-moving predators: “From my own recollection, I believe that every antelope in South Africa has to run for its...