CREATION BY EVOLUTION
birds, because they lie in the track of storms, and every year birds are arriving from the mainland in such numbers as to prevent the isolation of groups of them and the development of new types. This must not be understood to mean that new species do not arise on the continents; it merely means that they develop more rapidly under favourable isolation.
Islands like the Hawaiian group or St. Helena, which are very remote from any land and are of considerable geological antiquity, have birds and other land creatures so peculiar that their ancestry is obscure, or even unknown, so that it is difficult to decide what continent their ancestors really came from. This relation between the peculiarity of its species and the remoteness and antiquity of an island is just what we should expect according to the theory of evolution, but these factors should have no effect according to the theory of special creation.
An interesting illustration of this principle is afforded by the rails (Rallidae), a family of birds that is distributed all over the world, on continents and islands, except in the polar regions. The continental species can fly; many of the insular ones cannot. As the islands on which these flightless birds are found were never connected with any mainland, the advocate of the theory of special creation must hold that the birds were separately created on each island or reached it by crossing the sea; but they could not cross the sea by swimming, for no bird is able to swim across such breadths of sea. The birds must therefore have reached the islands by flying and have lost the power of flight after they settled in their insular homes. This loss of flight involves so great a modification of structure that the birds are assigned to new species and even to new genera, different from those to which their flying ancestors belonged. There is no doubt a close relation between the loss of the power of flight and a small,
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