Evolution and man's place in nature Author:Henry Calderwood Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: CHAPTER III THE RELATIONS OF ENVIRONMENT TO LIFE Organic life is insufficient to work out a history for itself. Dependence on Environment constitutes an es... more »sential feature in any theory of comparative zoology. Yet the energy belonging even to the minutest form of life is marvellous. Such organism is capable of seeking successfully the nutriment requisite for its support, the forces of Nature being ever at work producing fresh supplies for all forms of life. All organism must have, besides nutriment, space for movement, and conditions of satisfaction. Without these, life must disappear. But there are varying degrees of dependence. In the history of vegetable life, it is at its maximum, needful supplies being drawn from a comparatively limited area. Animal life, moving over a considerable space, competes for existing supplies, having its work prescribed by pressure of physical wants. In remote depths of the forest, rarely resounding to the footsteps of men, and in the great wilderness, this pressure is felt. The common conditions of life require unceasing toil to provide for life's wants, and to ward off life's dangers. Not always by co-operation are supplies found; more commonly there is individual struggle for ascendency over others of the same species, or destruction of lower species. It is with most animals, as with the fishes in a stream, the largest are in advance taking the food most attractive, the others have what is left. Search, struggle, and consequently the 'survival of the fittest,' are characteristic of animal life. Supply is limited; craving of appetite rules; and, unwittingly to the animals, advance in organic life results, in the history of all species. As an example of rarer kind, I take Owen's Memoir on the Aye-Aye, an animal belongingto Madagascar, and f...« less