Leigh Van Valen

Leigh Van Valen Maiorana ( born August 12, 1935 in Albany, † October 16, 2010 in Chicago) was an American biologist at the University of Chicago. His main areas of work were the evolutionary biology and biological systematics.

Life and career

Van Valen was known in particular for his formulation of an ecological species concept. The objective of this proposal is to define species by the niches they inhabit. At Van Valen a niche is to be understood as a complex conjunction of conditions of life, so that ultimately every niche exactly one type can be assigned. Although the ecological species concept further news can be awarded, it could not succeed as a universal concept. One problem is that a sufficient description of a niche itself already has to resort to species, so that a complete definition of Artbegriffs by the niche concept would be circular.

Influential also was Van Valen's evolutionary Red Queen hypothesis, which states that a type must be powerful constantly to maintain their current position. The reason is that according to Van Valen: A performance increase of a species usually leads to disadvantages for a different kind This must therefore also perform an evolutionary increase in performance in order to retain their position can. These dynamics can lead to an evolutionary " upgrade " from which any kind takes advantage. An example: A tree has a great advantage in a forest, when he grows up because he would collect the more sun rays. At the same time it blocks the sun for other trees that need to be even higher, consequently. This can lead to a height growth of trees that ultimately no way an advantage - possibly even only drawbacks - gives.

Van Valen used the name in his paleontological work on the adaptive radiation of mammals in the early Cenozoic from the novels of JRR Tolkien for naming fossil species, see Quirky scientific names in biology and medicine.