The Creation Explanation
|Beliefs and Interpretations of Evidence|
Animal and Plant Distribution23
Particular kinds of plants and animals are not found evenly distributed over the surface of the earth. Rather, each type is generally found to inhabit a certain range or area, or perhaps several separate areas. The science of zoogeography involves the study of the facts of animal distribution and an effort to explain or relate the observed data. The theories of animal distribution advanced by zoogeographers are usually grounded in evolutionary presuppositions. Such theories, however, afford many difficulties, for the evidence defies any simple or completely systematic analysis.
The basic assumption for secular zoogeography is that each animal originated at some point on the earth's surface and radiated from that point while undergoing continuing evolutionary adaptation. To correlate this idea with the facts of animal distribution requires many further assumptions. It has sometimes been found necessary to postulate former "land bridges" and island chains connecting now separate land masses when there is no geological evidence for such connections.
One example of a fact difficult to explain on an evolutionary basis is the existence is the existence of tapirs both in Latin America and in Malaysia on opposite sides of the world, with no populations occupying intermediate locations. A similar surprise comes from the distribution of true alligators, which are found only in the southeastern United States and in India and China.
An important assumption of secular biogeography is that great periods of time were required for the present distribution of animals to occur. It has been demonstrated, however, that animals can emigrate large distances in only a few years or decades by a variety of different means. The dispersal of insects and land animals, especially the smaller ones, can occur by wind, water currents, floating rafts of vegetation, and on the feet and plumage and in the alimentary tracts of flying birds. the rapidity with which immigrating plants and animals have become established on the volcanically decimated Krakatao Island since 1883 and on the new island of Surtsey off the coast of Iceland show that vast periods of time are not required for the development of soil, flora, and fauna on virgin land.
The present distribution of some plants and animals is entirely different from the past suggested by the fossil record. One example is provided by the group of trees which includes the Norfolk Pine, the Star Pine, and the Monkey Puzzle tree. These trees are now native to South America, but fossils of this group are found in North America, for example, in the petrified forest of Arizona. The Dawn Redwood was found still living in China, but its fossils are found in North America. The Gingko tree is another tree native to China, fossils of which are found in the United States. A similar situation is seen in the cases of the fossil insects and plants found in the Baltic amber and the plants, animals and insects in the Geiseltal lignite beds, but which are native to areas of the world far distant from Germany and the Baltic Sea.
23. Klotz, John W., ibid.(ref. 19), pp. 219-321.