Some Biogeographers, Evolutionists and Ecologists:
Willis's early botanical work revealed an excellent observer who excelled not only in morphological studies on both living and fossil plant forms, but also in compilations and literary synthesis. An accident in 1905 pushed him even further in the latter directions. He began to investigate patterns of geographic range within large taxa and, in the words of his Royal Society obituary, came up with "the working hypothesis...that the range of a taxon depends on the age of the taxon and conversely that range gives a clear indication of age. The word taxon is used because, though Willis first applied age and area to species, he later extended it to genera and families." Willis first presented his "age and area" theory in detail in a 1915 work on the endemic plant species of Ceylon, and published his definitive treatment of the concept in the book Age and Area in 1922. Willis's data were on the whole unconvincing, as was his abandonment of natural selection principles in favor of an evolutionary process driven by major mutation events (extending ideas first presented some years earlier by Guppy); the combined effect was the posing of a process in which large taxa evolved first and then split up into smaller taxa through episodes of mutation-occasioned divergence. The "age and area" theory attracted some interest for about twenty years, but support for it was clearly on the wane by the time of Willis's late books The Course of Evolution and The Birth and Spread of Plants (though each of these works contained some interesting ideas).
--born in Birkenhead, England, on 20 February 1868.
For Additional Information, See:
--Biographical Memoirs of Fellows of the Royal
Society, Vol. 4 (1958): 353-359.
Copyright 2005 by Charles H. Smith. All rights