Alcide d’Orbigny: a harbinger of the Chicago approach a century and a half ago

MANCEÑIDO, M.O.; DAMBORENEA, S.E.

Santa Cruz de la Sierra, Bolivia

Congreso; 5° Congreso Latinoamericano de Paleontología; 2002

Sociedad Paleontológica de Bolivia

One of the least appreciated facets of Alcide d´Orbigny´s impressive contribution to natural history, concerns his life-long, profound interest in the implications of detailed knowledge of the succession of life on a global scale. From 1839 onwards, he embarked on such ambitious projects as his "Paléontologie Française", the "Prodrôme de Paléontologie Strtaigraphique Universelle" and the "Course Elémentaire de Paléontologie Stratigraphique". His motive was apparently rooted in his enthusiasm for constructing a comprehensive data-base of the universal palaeontological record, in order to be able to derive empirical conclusions and/or generalizations about the successive steps in the progressive "course of colonization of the planet by animals, since the most ancient geological time to the present day". He was clearly aware that the evidence already accumulated by vertebrate palaeontologists amounted to only one sixth of the fossil animal genera then known (and twelve times less, at species level). His painstaking work of compilation, that would in current parlance be called "data gathering" was exerted paying due attention to aiming at a unified, consistent, taxonomy, and took over a decade to complete. He then attempted an analysis of his raw data, comprising 24000 species grouped into 1600 genera, within the four main branches then recognized: "vertebrates", "annelides", "molluscs" and "radiates", which he presented to the Paris Academy of Sciences a little over a century and a half ago. From the figures compiled in his table, d´Orbigny addressed the following questions: (a) the time of appearance of the animal orders as compared to their respective numbers during the ages of the Earth, (b) periods of increase or decrease of the animal orders throughout the geological ages of the world, as compared with the branch they belonged to, and (c) the time of appearance of the animal orders through the geological ages, with regard to the "degree of perfection of the ensemble of their organs" (i.e. level of overall evolutionary development). Such insightful perspective, focussing on issues like patterns of biodiversity, evolution and faunal turnover through Phanerozoic time, recalls the approach followed by contemporary scientists like the late Jack Sepkoski, Dave Raup (plus several others), and reveals that Alcide d´Orbigny was ahead of his time. Hence, one may speculate that if d´Orbigny had had the benefit of access to modern informatics and computing facilities, he might well have qualified for admission into the "Chicago School of palaeontological thought".