A mathematical theory of evolution, based on the conclusions of Dr. J. C. Willis, F.R.S. Offprint

1924. Yule, G. Udny (1871-1951). A mathematical theory of evolution, based on the conclusions of Dr. J. C. Willis, F.R.S. Offprint from Philosophical Transactions of the Royal Society of London, series B, 213 (1924). 21-87pp. 304 x 232 mm. Original printed wrappers. Fine. First Edition, Offprint Issue. In this landmark paper British statistician G. Utny Yule introduced the Yule process (now known as preferential attachment process), along with the Yule distribution (now known as the Yule-Simon distribution) as a means of mathematically analyzing evolutionary processes. "A preferential attachment process is a stochastic urn process, meaning a process in which discrete units of wealth, usually called “balls,” are added in a random or partly random fashion to a set of objects or containers, usually called “urns.” A preferential attachment process is an urn process in which additional balls are added continuously to the system and are distributed among the urns as an increasing function of the number of balls the urns already have . . . " classic example of this is the growth in the number of species per genus in some higher taxon of biotic organisms. New genera (“urns”) are added to a taxon whenever a newly appearing species is considered sufficiently different from its predecessors that it does not belong in any of the current genera. New species (“balls”) are added as old ones speciate (i.e., split in two) and, assuming that new species belong to the same genus as their parent (except for those that start new genera), the probability that a new species is added to a genus will be proportional to the number of species the genus already has. This process, first studied by British statistician Udny Yule [emphasis ours], is a linear preferential attachment process, since the rate at which genera accrue new species is linear in the number they already have. "Linear preferential attachment processes in which the number of urns increases are known to produce a distribution of balls over the urns following the so-called Yule distribution"(Wikipedia, “Preferential attachment”). . (Inventory #: 52095)