Ernst Mayr (1904-2005).

TLDR: Ernst Mayr was one of the principal architects of 20th century evolutionary biology and his principal contribution was the elaboration of the idea of allopatric speciation, the idea that geographic isolation leads to reproductive isolation leading ultimately to new species.

Abstract: The story goes that, with the intention of celebrating Ernst Mayr’s 100th birthday by commissioning an essay on his life and work, Science asked him who would be the best person to write such an essay. Ernst Mayr is supposed to have replied, “Ernst Mayr of course”! The resulting essay entitled “80 Years of Watching the Evolutionary Scenery” (Mayr 2004) – as sharp and precise as it is rich in historical detail – is a special gift to be savoured as it gives us a unique glimpse of the evolution of evolutionary thought in the 20th century. Even more important, it gives us a glimpse of the evolution of Ernst Mayr’s thoughts. And there is very good reason to be interested in the evolution of Ernst Mayr’s thoughts, not only because it spanned a record 80 years, but also because he was one of the principal architects of 20th century evolutionary biology. Ernst Mayr remains best known for his early work in the 1930’s and 1940’s, culminating in his Systematics and the Origin of Species (1942). This, along with Theodosius Dobzhansky’s Genetics and the Origin of Species (1937) and George Gaylord Simpson’s Tempo and Mode in Evolution (1944), constituted the “Modern Synthesis” of evolution. The modern synthesis brought together genetics, systematics and paleontology to explain the mechanism of the origin of species with a degree of success that, notwithstanding the title of his book, was impossible for Darwin. Mayr’s principal contribution was the elaboration of the idea of allopatric speciation, the idea that geographic isolation leads to reproductive isolation leading ultimately to new species. This stemmed from his biological species concept which led him to famously define species as “a group of actually or potentially interbreeding natural populations reproductively isolated from other such populations”. Mayr’s early ideas evolved in the backdrop of his field work on the birds of New Guinea and the tropical southwest Pacific islands. Less well known to non specialists are Mayr’s mammoth contributions as an ornithologist – he is said to have “described more species and subspecies of living birds than anyone else of his or subsequent generations” (Diamond 2005). All this came about by a curious set of circumstances. Born in Kempton, Germany, on 5 July 1904, Mayr was all set to faithfully follow the family tradition of a career in medicine when he sighted and carefully observed a pair of rare ducks called red-crested pochards, a species that had not been sighted in Germany for 77 years. This of course was only possible because his father had inculcated in him an abiding interest in nature by taking him out on Sunday natural history expeditions. That’s something to think about and emulate for those of us in India who keep complaining about our young people being blindly driven to medical and engineering colleges! The citing of the pochards brought Mayr in contact with Erwin Stresemann, a famous German ornithologist of the time. Interestingly, it is the same Erwin Stresemann that India’s foremost ornithologist Salim Ali went to train with and about whom he wrote “I considered him my guru to the OBITUARY