Where Did the Ancestor Arise? An Alternative Theory to Locate the Center of Origin

Abstract

A new theory is proposed to estimate the center of origin of organism tribes. The theory, differing from either of those in evolutionary or cladistic biogeography, is constructed on a combination of the so-called stage theory in phylogeny with the same in distributional process. The two most important traits involved are that : 1) formation of new (daughter) tribes is confined to the earlier stages in phylogeny of the mother tribe, and 2) dispersal of tribes is made stepwise. In the application of the theory, data concerning the phylogeny, especially the exact mother-daughter tribe relationships, and the distributional patterns of extant daughter tribes should be fully taken into account. Then, the theory dictates that the center of origin or the place of birth of the most-ancestral mother tribe is to be sought with reference to the distributional range of the first daughter tribe of the latest or ultimate generation, which was derived in turn from the first daughter tribe of the penultimate generation, which again had been derived from the first daughter tribe of the antepenultimate generation, etc. Finally, some remarks on the limit in applicability of the new theory are given.