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Phylogenetics and Biogeography
Vol. 21, No. 1 (Mar., 1972), pp. 69-79
Stable URL: http://www.jstor.org/stable/2412259
Page Count: 11
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Because of the nature of the speciation process we have to admit (1) that nature has created a system of its own that is in principle hierarchic, and (2) that the biological species and strictly monophyletic species groups have been the real units of evolution. Hence only a system expressing nature's hierarchy of sister groups can function adequately as a general biological reference system. Causal biogeography, whose main method is the investigation of geographical replacement within properly reconstructed sister-group systems, is indissolubly connected with the reconstruction of nature's hierarchy. In his criticism of Hennig-Brundin, Darlington (1970) has not considered these principles. He has also overlooked that dispersal, seen in the time perspective, is a multiple process including progression in space, evolutionary change (development of comparative apomorphy), and speciation. Hence his criticism is neither relevant nor progressive.
Systematic Zoology © 1972 Oxford University Press