3 The New York Years (1931–1953)

358 11 History and Philosophy of Biology—Mayr’s Third Synthesis
important for selection as are mutations. Selective demands encounter numerous
constraints and cannot produce perfection. Every genotype is a compromise
between various selective demands. The “balance” school (Dobzhansky, Lerner,
Mayr) considers the genotype a harmoniously balanced system of many genes
with the heterozygotes often superior to the homozygotes. Fitness values of genes
depend on their “genetic milieu” and hence on the resulting individual phenotype
(Chetverikov). A high level of allelic polymorphism was confirmed through enzyme
electrophoresis since 1966 and proved the enormous genetic variability of
natural populations.
The genetic studies of speciation in Hawaiian Drosophila by H. Carson in 1975
convincingly confirmed Mayr’s theory of peripatric speciation from founder populations.
Sympatric speciation is considered to be possible in certain families
of freshwater fishes and host-specific insects. The greatest unsolved problem in
speciation research remains that of the genetic basis of speciation. Perhaps only
a small number of genes are involved. Paleontologists traditionally concentrated
on the “vertical” component of evolution until Eldredge and Gould (1972) proposed
their model of “punctuated equilibria” which was based on Mayr’s (1942e,
1954c) model of geographic speciation in small isolated populations. The claim
of Eldredge and Gould (l.c.) that the new species originate by saltations as “hopeful
monsters” (sensu R. Goldschmidt), not as a populational process, was later
retracted.
Biographical studies
After he had written a few biographical contributions from the 1930s to the 1960s,
Mayr published numerous historical accounts on the lives of biologists during the
1970s (ten), 1980s (ten), 1990s (twenty-seven) and 2000s (eighteen). Among these
are (1) brief obituary notices or personal memories of friends and colleagues,
(2) biographies or memories of biologists which include summaries of their scientific
work, and (3) biographies of biologists with fairly extensive discussions of
their scientific contributions (see listing below). Among these are many brief memories
or obituaries of ornithologist friends in Germany (E. Stresemann, B. Rensch,
G. Schiermann, R. Zimmermann) and in the United States (D. Amadon, H. Birckhead,W.Drury,E.T.Gilliard,L.Sanford)aswellasformalcontributionstothe
Dictionary of Scientific Biography (1975, 1976, 1990) for F. Chapman, D. Davis,
K. Jordan, G. Noble, R. Ridgway, M. Sars, C. Semper, K. P. Schmidt, E. Stresemann,
and C. O. Whitman. Although Mayr was limited in each of these latter cases to only
one thousand words, even this short treatment required a lot of research. Among
additional obituaries of ornithologists are those of E. Hartert, J. Delacour, D. Lack,
and A. Wetmore most of whom Mayr had known well over many years. I included
in the text of this biography E. Mayr’s memories of friends from the ten summers
he spent at Cold Spring Harbor (A. Buzzati-Traverso, E. Caspari, M. Delbrück,
Th. Dobzhansky, C. Stern, and B. Wallace) and of several others (R. Goldschmidt,
J. Moore, F. Weidenreich).