3 The New York Years (1931–1953)

282 8 Evolutionary Biology—Mayr’s Second Synthesis
This encouraged the search for new approaches in the treatment of this disease.
Mayr emphasized the need for an adequate consideration of multiple causation,
“a process particularly important in the shaping of the phenotype,” for which both
genotypic and environmental factors are important. The purely environmental
theory of schizophrenia has been abandoned.
Explanations of concepts and definitions of terms. The clarity of discussions of theoretical
concepts depends on clear definitions of terms. Therefore Mayr included
in most of his books detailed glossaries and published an article on the “Origin
and history of some terms in systematics and evolutionary biology” (1978c),
many of which he had proposed or introduced from foreign languages into the
English literature. Examples are: allopatric, cladogram, founder principle, genetic
revolution, nondimensional species, phenetics, population thinking, semispecies,
sibling species, superspecies, teleonomic and others. He discussed and analyzed
repeatedly theoretical concepts like “Darwinism,” “adaptation” and “selection.”
As late as 1997(e), Mayr devoted a discussion to the subject of selection coining the
new term “selecton” for the target or object of selection (the gamete, the individual
organism, and certain social groups of cooperating animals or early humans).
However, there is no “species selection,” because the species as an entity does not
answer to selection. When one species replaces another one due to competition,
then this “species turnover” is due to individual selection discriminating against
the individuals of the losing species. The expression “selection for” is used for
any aspect of the phenotype (or the phenotype as a whole) that favors survival or
reproductive success and which, therefore, will be favored by selection.