Walter Frank Raphael Weldon (15 March 1860 — 13 April 1906) was an English evolutionary zoologist and biometrician.
Weldon was the second child of the journalist and industrial chemist, Walter Weldon , and his wife Anne Cotton. Medicine was his intended career and he spent the academic year 1876/7 at University College London. Among his teachers were the zoologist E. Ray Lankester and the mathematician O. Henrici . In the following year he transferred to King's College London and then to St John's College, Cambridge in 1878.
Weldon studied with the morphologist Francis Balfour who influenced him greatly; Weldon gave up his plans for a career in medicine. In 1881 he gained a first-class honours degree in the Natural Science Tripos; in the autumn he left for the Naples Zoological Station to begin the first of his studies on marine biological organisms. Upon returning to Cambridge in 1882, he was appointed university lecturer in Invertebrate Morphology. Weldon’s work was centred around the development of a fuller understanding of marine biological phenomena and selective death rates of these organisms. In 1889 he succeeded Lankester in the Joddrell Chair of Zoology at University College London.
Weldon’s interests were changing from morphology to problems in variation and organic correlation. He began using the statistical techniques that Francis Galton had developed for he had come to the view that "the problem of animal evolution is essentially a statistical problem." Weldon began working with his University College colleague, the mathematician Karl Pearson. Their partnership was very important to both men and survived Weldon's move to the Cxford chair of comparative anatomy in 1899. In the years of their collaboration Pearson laid the foundations of modern statistics. Magnello emphasises this side of Weldon's career.
In 1900 the work of Gregor Mendel was rediscovered and this precipitated a conflict between Weldon and Pearson on the one side and William Bateson on the other. Bateson, who had been taught by Weldon, took a very strong line against the biometricians. This bitter dispute ranged across substantive issues of the nature of evolution and methodological issues such as the value of the statistical method. Will Provine gives a detailed account of the controversy. The debate lost much of its intensity with the death of Weldon in 1906.
- K. Pearson (1906) Walter Frank Raphael Weldon. 1860–1906. Biometrika 5: 1–52.
- W. B. Provine (1971) The Origins of Theoretical Population Genetics. University of Chicago Press.
- E. Magnello (2001) Walter Frank Raphael Weldon, Statisticians of the Centuries (ed. C. C. Heyde and E. Seneta) pp. 261-264. New York: Springer.
For an example of Weldon’s use of statistical methods see
There is a photograph of Weldon at