Ornithology, Evolution, and Philosophy 123

A Modern Unified Theory of Evolution 189
not find out very much about the origin of new genetic characters nor about their
transmission from one generation to the next. On the other hand, the taxonomist
will be able to give answers to certain questions which are not attainable by the
geneticist since speciation is not a purely genetic process” (Mayr 1940c: 249) and
in a lecture next year he said: “We seem to be at the beginning of a new phase of
the study of evolution, that is the study of the origin of the discontinuities between
species. This is a typical border line field which must be studied jointly by the
naturalist and ecologist, by the geneticist and taxonomist” (Mayr 1941i: 139).
Mayr had been thoroughly influenced by the ideas of Stresemann and Rensch
at the Berlin Museum of Natural History who fully endorsed the biological species
concept and the importance of geographical variation and barriers for the process
of speciation, and he assumed that any taxonomist with some knowledge of
the literature would also adopt this concept and interpretation. However, several
experienced workers published critical statements like Goldschmidt (1933,1935)
who denied geographical speciation, Robson and Richards (1936) who minimized
it and the paleontologists (Osborn, Beurlen and Schindewolf) who ignored it.
“I suddenly realized that it was important to present massive documentation in
favor of geographic speciation so that at least this particular uncertainty could be
eliminated from the panorama of evolutionary controversies” (Mayr 1980n: 420).
At the American Association for the Advancement of Science (AAAS) meeting
in Columbus, Ohio in December 1939, the American Society of Naturalists and
the Genetics Society of America sponsored a joint symposium on “Speciation.”
Th. Dobzhansky as organizer invited Mayr to participate as a speaker which was
a decisive step into his evolutionary career. It was the first time that he generalized
on aspects of geographic variation and speciation in birds using many of his
examples from the Pacific islands and New Guinea (Mayr 1940c).
The story of his presentation on 28 December 1939 is spiced with a slight bit of
malice (Mayr 1997d: 179):
“The speaker scheduled just before me was the famous geneticist Sewall Wright,
a brilliant mathematician, but not an orator, to put it mildly. We lectured in the
largest hall at Ohio State, seating several thousand people. The stage from which
we spoke was huge; it was also used for concerts and for theatrical performances.
Therewasalecternwithafixedmicrophoneattheveryfrontoftheplatform,and
a series of blackboards some way at the back of it. Wright started his lecture in the
front of the microphone, but became totally inaudible when he soon went back to
the blackboards, on which he wrote a long series of mathematical formulae. Once
in a while he became aware that he probably could not be heard by the audience,
and would walk about half way toward the microphone, but of course was still
quite inaudible. Soon he happily returned to the blackboard and his mathematics.
This went on for nearly an hour.
Most of the huge audience had come to hear the famous Sewall Wright, and
after his lecture there was a great exodus. Fortunately, those truly interested in
speciation stayed. When I came onto the platform, having learned from Sewall
Wright what not to do, I stayed right next to the microphone and I showed a set of
beautiful color slides of the geographic speciation pattern of the birds collected by