PDF - Wallace Online

THE DEVELOPMENT OF HUMAN RACES 173Different Effects of Natural Selection on Animals and on ManIn order to answer these questions, we must consider whyit is that natural selection acts so powerfully upon animals,and we shall, I believe, find that its effect depends mainlyupon their self-dependence and individual isolation. A slightinjury, a temporary illness, will often end in death, becauseit leaves the individual powerless against its enemies. If anherbivorous animal is a little sick and has not fed well for aday or two, and the herd is then pursued by a beast of prey,our poor invalid inevitably falls a victim. So, in a carnivorousanimal, the least deficiency of vigour prevents its capturingfood, and it soon dies of starvation. There is, as ageneral rule, no mutual assistance between adults, whichenables them to tide over a period of sickness. Neither isthere any division of labour ;each must fulfil all the conditionsof its existence, and, therefore, natural selectionkeeps all up to a pretty uniform standard.But in man, as we now behold him, this is different. Heis social and sympathetic. In the rudest tribes the sick areassisted, at least with food ;less robust health and vigourthan the average does not entail death. Neither does thewant of perfect limbs or other organs produce the same effectsas among animals. Some division of labour takes place ;theswiftest hunt, the less active fish, or gather fruits ;food is, tosome extent, exchanged or divided. The action of naturalselection is therefore checked ;the weaker, the dwarfish, thoseof less active limbs, or less piercing eyesight, do not suffer theextreme penalty which falls upon animals so defective.In proportion as these physical characteristics become ofless importance, mental and moral qualitieswill have increasinginfluence on the well-being of the race. Capacity foracting in concert for protection, and for the acquisition offood and shelter ; sympathy, which leads all in turn to assisteach other; the sense of right, which checks depredationsupon our fellows the smaller; development of the combativeand destructive propensities self-restraint in ; present appetites,and that intelligent foresight which prepares for thefuture, are all qualities that from their earliest appearancemust have been for the benefit of each community, and would,