Il "Systema Naturae": la classificazione e la nomenclatura dei viventi

The Linnean “systema naturae”: classifying and naming all living beings. Linnaeus introduced into biological systematics two main ideas: the sexual classification system, and the binomial nomenclature. Both classification and nomenclature were aimed at the same scope: to provide botany with an effective information storage and retrieval system. Linnaeus main concern was not as much to describe plants, as to deal with their diversity. The sexual system is basically a way of ordering plants into classes and orders, characterised by the number of stamens and the number of pistils respectively. Although quite artificial in its nature, this system is highly practical and unambiguous. The binomial system of nomenclature is a straightforward hierarchical method, where all species are named after the genus to which they are attributed (generic name) followed by a specific epithet. The Linnaean nomenclature was immediately and widely accepted, while the classification system was the object of discussion and polemics throughout the second half of the eighteenth century. Some scientists hold that the very attempt to classify the living diversity was an unrealistic task, due to the unlimited variety of life. An outstanding representative of this way of thinking was J. W. von Goethe. Other scholars, mainly belonging to the French scientific world, judged it unnatural to classify plants just based on the number of stamens and pistils. This school had in J.-L. Buffon its main leader and in M. Adanson the one who tried to practically develop a classification system shaped after this views. Finally, to some authors the very fact of seeing sex in flowers was scientifically unconvincing as well as morally unacceptable. In spite of so many different objections, the Linnaean system rapidly overcame all competing systems and, by the end of the Century was largely adopted in all Europe. New views developed during the Nineteenth Century drew systematists to explore other taxonomic criteria. From the beginning of the Century, the development of biogeography first, and the evolutionary interpretation of biodiversity later, resulted in a deep reformation of systematic biology. Nevertheless, the Linnean legacy still survives, not only in the nomenclature system, which is still in use, but even more in the basic principle that dealing with plant and animal diversity requires an homogeneous, coherent, rigorous classification system.