Until the end of the 18th century most scientists accepted Biblical accounts of the history of the earth and of life on earth literally. They therefore believed that God created each species of life separately, and more or less in their present forms. Most scientists also believed that, in the distant past, a great flood submerged the Earth, killing all land-based animals except those ushered into his Ark by Noah. They also believed that when the flood subsided, Noah's ark was beached on Mount Ararat (located in modern Turkey) and its cargo of animals formed the basis for the recolonisation of the Earth with animal life.
Many early scientists initiated scientific investigations of the world to illustrate the accuracy of the Bible and thus to add lustre to the common man's appreciation of the glory of God.
However, where scientific investigation showed that a literal interpretation of certain parts of Scripture could not be squared with objective analysis, these scientists did not shrink from accepting the obvious conclusion - certain parts of the Bible should not be interpreted literally.
This is in stark contrast to modern-day creation-science, whose practitioners seem interested in science only insofar as it can be used to produce evidence to support literal interpretation of the Bible.
The 17th-century German Jesuit, Athanasius Kircher, is an example of scientific analysis which comfortably squared biological knowledge at the time with the story of Noah's Ark as told in the Book of Genesis.
Kircher calculated that the lower deck of the ark had 300 stalls, each big enough to hold an elephant. He reasoned that the middle deck was used to store food and that the top deck housed 200 birdcages in addition to Noah and his family.
Kircher knew only 130 species of mammals, 150 species of birds and 30 species of snake. Fish, reptiles and insects were presumed to be capable of surviving the flood unassisted, and therefore Kircher's reconstruction of the Ark provided ample space for life as he knew it.
No European of Kircher's time had the remotest idea of the abundance of species living beyond Europe. This was not appreciated until the 18th century, when explorers returned from voyages with amazing specimens of kangaroos, parrots, and thousands of other exotic creatures.
This knowledge sank the lifeboat theory of the ark under the weight of the problem of overloading. It would simply be impossible to fit so many species into a boat.
If the ark had to go as a serious explanation, this did not necessarily mean that the story of the flood which killed off life, and the mountain from which life again spread, could not be retained.
Carolus Linnaeus, the great Swedish botanist and taxonomist, attempted to do this in 1744. He proposed that God, after the flood, again created two of every living thing on Mount Ararat.
Linnaeus reasoned that the mountain is high enough to harbour a wide range of conditions, from tropical at the bottom to arctic at the top. Each species subsequently migrated from this centre of creation to the ecological zone it inhabits today.
The theory of Linnaeus in turn failed to pass the test of rigorous analysis. Biologists at the time knew that every species is especially adapted to its habitat, climate zone and geographical area. This made it impossible to visualise how most species could migrate large distances from Mount Ararat to reach their current resting niches.
The thinking of Linnaeus was succeeded by the theory that each species was created in the area it now inhabits. In 1858 the world's six main biogeographical regions were defined: the Nearctic (North America); the Neotropics (South and Central America); the Palaearctic (Europe, Northern Asia, Northern Africa); Ethiopian (Tropical and Southern Africa); Oriental (South-east Asia); and Australian.
The British biogeographer, Edward Forbes, was intrigued by the observation of disjunct distribution, i.e., the presence of the same species in widely scattered places. For example, many Alpine species live in the Swiss Alps, the Scottish Highlands, the Caucasus mountains and northern Scandinavia.
These regions are separated by climatic belts not suitable for Alpine species. Was each species created separately at each site?
Forbes argued in the early 19th century that, in the past, all northern Europe had a very cold climate during a glacial period when Alpine species were widely dispersed. With the passing of the glacial period the Alpine species survived only on widely separated mountain regions in the far north.
After Forbes, biogeographers concentrated on change - geological, geographical, climatological and biological - when they proposed explanations for the present distribution of life on earth.
Charles Darwin and Alfred Russell Wallace were bio geographers of the highest calibre. Darwin said in The Origin of Species - "When on board HMS Beagle, as naturalist, I was much struck by certain facts in the distribution of the inhabitants of South America. Those facts seemed to me to throw some light on the origin of species - that mystery of mysteries."
Darwin and Wallace used their detailed observations of the current distribution of species, together with their knowledge of biological inheritance, geological and geographical change over deep time and the brilliant new insight of natural selection, to explain the broad outlines of the evolution of life from simple beginnings to its current diverse flowering. This explanation requires no special creation of individual species and no heroic intervention by Noah.
The rise and fall of the belief amongst biogeographers that each biological species was separately created is chronicled in the book The Secular Ark by Janet Browne (Yale University Press, 1984).
William Reville is a senior lecturer in biochemistry and director of microscopy at UCC.