The Flood and Biogeography
A creationist interpretation of biogeographical distributions must begin with the Flood. Unfortunately, creationists do not have a generally accepted flood model, and the Bible does not tell us whether fossils were all produced by the Flood. Much more study is needed in this area. However, we do not know of any other process that could account for the richness of the fossil record within a short chronology for life on Earth, and so we accept, as a working hypothesis, that most of the fossil record is the result of the catastrophic events of the Flood.
The Biblical Flood is described very briefly in Genesis 6-9. The passage focuses on the experience of Noah and his family, and the effects on the animals are only of secondary interest. The passage emphasizes two important features: the global extent of the flood, and the ark as a refuge from the flood.
A global flood. The Flood described in Genesis was global in extent. However, the brief, general description in Genesis leaves considerable leeway in interpreting the details as they apply to biogeography. For example, it seems reasonable to suppose that the Flood may not have had the same effects in all regions of the earth. Flooding could have been the result of torrential rains, or of rising sea levels, or of gigantic tsunamis due to tectonic movements, or of water thrown from the ocean by asteroidal impacts. These factors may have been of different extent in different regions. Some regions may have been inundated for long periods of time while other regions may occasionally have had some mountaintops rising temporarily above the water surface. The Biblical text may even permit the idea that the flood covered the land surface sequentially, rather than simultaneously. The common coverage of the present continents with marine sediments indicates that all regions of the earth were covered at one time or another during the flood, whether sequentially or simultaneously.
The ark as a refuge for terrestrial vertebrates. It is obvious that a flood would have different effects on marine creatures and on terrestrial creatures. Terrestrial vertebrates in particular would be unlikely to survive a global flood, while many marine invertebrates would be expected to survive. Considerable speculation and discussion has occurred over how the flood might have affected different types of organisms, and which animals were on the ark.
It appears that the ark was designed specifically to save terrestrial vertebrates, including humans. Numerous invertebrates probably came with them, and Noah undoubtedly took some seeds with him to plant after the flood, but many species from these groups must have survived through the flood. Genesis 7:21-23 specifies the kinds of creatures that were to be destroyed in the flood: those that walk on the surface of the ground and breathe through nostrils. This description applies only to terrestrial vertebrates. The ark was designed to preserve representatives of the terrestrial vertebrates, which would otherwise be obliterated by the flood.
Refugia for other groups. The Flood seems to have involved a complex series of catastrophic events that affected the entire surface of the earth. Billions of fossils are found in the rocks, probably the result of these catastrophic events. If the catastrophic processes that killed and preserved these fossils were uniformly applied to all areas of the earth's surface, it is unlikely that any macroscopic organisms could survive. Yet the oceans and rivers have a wide diversity of organisms that would not be expected to find refuge in the ark. These organisms are descended from flood survivors, and seem to imply the existence of local areas where conditions were calm enough to permit some individuals to survive. Such areas could be called “refugia.”
There may have been numerous marine refugia, as well as fresh-water refugia in which the present groups of marine and fresh-water organisms were preserved through the Flood. Mats of floating vegetation may have acted as refugia to preserve a diversity of terrestrial invertebrates through the Flood, including insects, spiders, worms, etc. After the Flood, these refugia, scattered in various parts of the world, would act as dispersal centers which would serve to quickly populate the newly available habitats of the post-Flood world.
Extinction. Not all species were preserved through the Flood. Many thousands of fossil species are extinct, most of them presumably destroyed by the Flood. Even entire groups of species were destroyed, including the trilobites and ammonites in the sea, the dinosaurs and therapsids on the land, and the pterodactyls in the air. The fossil record also shows evidence of mass burials in which many individuals were rapidly killed and covered by sediments. Frequently, large numbers of species disappear from the fossil record at the same stratigraphic level, a phenomenon known as a mass extinction. These observations suggest that survival through the flood may have required exceptional circumstances.
L. James Gibson
Geoscience Research Institute