WHY WE MUST BE EVOLUTIONISTS
nobler forms of life. Among back-boned animals the first were the fishes. These led to the amphibians, and these were succeeded by reptiles. Later there arose birds and mammals. Throughout the ages, life has been slowly creeping upward. Detailed pedigrees are disclosed in the rocks, some of them with marvellous perfection, as in the evolution of horses and elephants, camels and crocodiles. For some animals, such as fresh-water snails and marine cuttlefishes, there is an almost perfect succession of fossils, forming a chain in which link 10 is very different from link 1, yet just a little different from link 9, as link 2 is a little different from link 1. For such animals we can almost see evolution anciently at work!
The geographical evidences are also endless. If the present state of affairs is not the outcome of a natural process of evolution, why should the fauna of oceanic islands be restricted to those animals which can be accounted for by transport over the sea by currents and by winds, or on the feet of birds? Thus there are no amphibians on oceanic islands, because few amphibians can endure salt water.
The inhospitable Galapagos Islands are said to be the submerged tops of cold volcanoes, which belong to an ancient peninsula that became first an island and then an archipelago. They have a peculiar fauna, which includes the famous giant tortoises. There are ten different kinds of giant tortoise on ten different islands, and those that are on the islands that are farthest apart are most unlike. There are five different kinds in different parts of the largest island, which is called Albemarle. Now if we consider thoughtfully these facts what can we find them to mean except that isolated groups of one ancient stock of the original peninsula have varied slightly on one or another island and that the isolation prevented any pooling or blending of the new
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