Ornithology, Evolution, and Philosophy 123

12 Summary:
Appreciation of Ernst Mayr’s Science
As a young naturalist Ernst Mayr became familiar with the birds of his native
Germany in the years after World War I and spent every free minute of his time in
the woods and fields watching falcons, thrushes and warblers and along the lakes
and rivers observing ducks and plovers. Following a family tradition he entered
medical school in 1923, but soon came under the influence of Dr. Erwin Stresemann
(1889–1972) in Berlin, the country’s leading ornithologist, who saw in this young
student “a rising star, of fabulous systematic instinct.” He enticed him to switch to
zoology by offering to place him on an expedition to the tropics after finishing his
PhD dissertation. This had been Mayr’s dream since he was a boy and he could not
resist. He moved to the University of Berlin and accepted a dissertation topic from
Erwin Stresemann passing his PhD examination summa cum laude in June 1926.
The foundation of all of Mayr’s later theoretical interests in species and speciation,
evolution, and the history and philosophy of biology was laid during his
student days. Already in 1924, when he was 19 years old, he discussed with Stresemann
the species question, the analysis of phylogenetic relations among closely
related bird species, rates of differentiation, and convergence (from a Lamarckian
point of view). The subject of human inheritance and genetics fascinated him
since he was a medical student. Already in 1927 Mayr deplored in print “how little
geneticists and systematists cooperate even today.” Therefore he was enthusiastic
when, after moving to New York in 1931, he read an article by T. Dobzhansky, a naturalist
and geneticist from Russia, on the geographical variation in lady-beetles
and exclaimed: “Here is finally a geneticist who understands us taxonomists!”
They cooperated closely during the following years, especially after Dobzhansky
had moved to Columbia University in New York City in late 1939, when they became
close friends. From then on they discussed problems of the new systematics,
genetical aspects of speciation and other topics of mutual interest.
The Fisherian synthesis of the 1920s and early 1930s united the Darwinian theory
of natural selection with modern genetics solving one of the two main problems
of evolution, the problem of phyletic evolution of individual populations, through
the work of the mathematical population geneticists R.A. Fisher (1930), S. Wright
(1931), and J.B.S. Haldane (1932). The other main problem of evolution which the
geneticists had left open, the origin of biodiversity or multiplication of species, was
solved during the evolutionary synthesis (1937–1950), when Dobzhansky (1937),
Mayr (1942e), Huxley (1942), Simpson (1944), Rensch (1947), Stebbins (1950) and
several other workers in the Old World established the synthetic theory of evolution.
With the publication of his book, Systematics and the Origin of Species