Original paper

The Darwinian dilemma of the first species and the principle of pseudo-monophyly of Phanerozoic diversity

Reif, Wolf-Ernst


In his publications, Darwin avoided the discussion of the evolutionary origin of the mechanisms of life. His principle of the Unity of Type states that every taxonomic group of the Phanerozoic is built according to its own unique bauplan and is hence derived from one single ancestor. This leads to the inevitable conclusion that the diversity of the Phanerozoic dates back to a single progenitor species. However, according to the laws of ecology a single plant or animal species could not survive. Hence, Darwin stated that life on Earth started with about 10 first plant and animal species, which is in accordance with the ecological laws. Most of the descendants of most of the first species died out, whereas the remaining ones underwent convergent evolution which led to the unity of type ("pseudo-monophyly"), and divergent evolution which led to the enormous Phanerozoic diversity on the species and on the ecosystem level. Woese's (2002) model of the "Darwinian Threshold" provides a modern mechanism of Darwin's "pseudo-monophyly", especially of the almost-universality of metabolic mechanisms and genetic code, of the several or many species at the root of the phylogenetic tree, and of the early extinction of other early species.


horizontal gene transferorigin of lifetree of lifephylogenybauplane