jueves, 24 de junio de 2010

Biological Species Concept

Jimenez Silva, C. L.

Universidad Industrial de Santander
The biological species concept defeat the "typological thinking", Mayr's foundations to refute it was the population biology vision, with which reverses the meaning of species as type and replaced with a statistical group approach. the Population biologist emphasizes the uniqueness of each thing in the organic world. Individuals, or any kind of organic entity, build populations from which we can determine the arithmetic mean and the statistical variation. Averages are merely statistical abstractions, only individuals have actually made up of those populations. For the typology, the type (eidos) is real and the variation an illusion, while for the population biologist the type (average) is an abstraction and only the variation is real. (MAYR, E. 1959)

A population forms a "specie" only with respect to other populations. Belonging to a different specie is not about differences, it is about distinguish and relate. The Biological interpretation introduce to the multidimensional concept of species, which means that it should be considered as a group of stocks that actually or potentially interbreed. Such species, to preserve their identity, can't coexist in the same place at the same time, applying the concept to allopatric species is determined on the possibility of mutual intersection. As the concept of "species" as Mayr that applies to biological individual, acquires a double meaning: on the one hand it refers to the dimensionless-that Mayr interpreted as the reproductive continuum, and secondly, concerns to the multidimensional condition, whereby the possibility of gene flow can be almost unlimited. It also includes raising Population meaning: "The species are natural population groups really or potentially interbreeding , reproductively isolated from other similar groups" MAYR, E. (1942). Comparable to those proposed by Dobzhansky, 1941, stating: "A species is a reproductive community wider ... of sexual individuals and that fertilize each other, they share a common gene pool".

One of the problems of the species is limited to the consequences of consider it was the result of a "category of thought" taking it to an artificial incompatible condition with the biological reality. Mayr criticizes the taxonomists, who believe that this concept treats individuals as an aggregate of inanimate objects, taking it as inappropriate for the dynamic behavior of a population change. Affirming that "The species is therefore a dynamic concept, population, inextricably tied to genetic recombination events, whose meaning makes possible the emergence or splitting of one species into another" (MAYR, E 1968). Defending and a realistic notion of species derived from their interactions with the environment and other species. MAYR, E. (1949) In the biological species concept, although two species are morphologically indistinguishable, each one has a genetic system, behavioral and ecological separate, isolated by a real biological discontinuity in a meaningful context specific population based on genetic transformation.

DOBZHANSKY, T.-: (1941) Genetics and the Origins of Species. Columbia, Biological Series, N.XI, 2a

MAYR, E.: (1959) Species concepts and definitions. En E. MAYR, E.: The species problem (Amer. Assoc. Adv. Sci. Publ. No. 50), 1-22.

MAYR, E.: Animal Species and Evolution., Ariel, 1968. p. 32

MAYR, E.: (1942 ) T(Systematics and the Origin of Species. Columbia University Press. New York.

MAYR, E.: (1949) Speciation and selection. Proc. Amer. Phil. Soc. 93:514-519.