Julia C. Keller, "Ernst Mayr, a leading evolutionary biologist, dies at 100 " (2005)

 Ernst Mayr, one of the world’s leading evolutionary biologists, died last month. He was 100.

Biologists credit Mayr with establishing the accepted definition of a “species” — an interbreeding population that can’t reproduce fertile offspring with other populations — and with influencing thought on how new species come into existence.

“Professor Mayr’s contributions to Harvard University and to the field of evolutionary biology were extraordinary by any measure,” Harvard history professor William C. Kirby said, calling Mayr a “leading mind of the 20th century.”

“He shaped and articulated modern understanding of biodiversity and related fields,” Kirby said.

Mayr was born in Kempten, Germany, in 1904. He originally planned to become a medical doctor, earning his degree from the University of Greifswald in 1925. Realizing world travel as a medical doctor was limited, Mayr raced through acquiring a zoology doctorate, focusing on ornithology. In 16 months, he was awarded a doctorate by the University of Berlin.

In 1927, at the International Zoological Congress in Budapest, Mayr met Lord Rothschild, an avid naturalist who was seeking a researcher to collect birds of paradise specimens for his natural history museum in London. For more than two years, Mayr made field expeditions to New Guinea and the Solomon Islands to study birds in the South Seas.

Like Charles Darwin, Mayr was profoundly influenced by his island voyages. However, unlike Darwin, Mayr used the concept of genetics to explain how isolated populations of birds acquired different traits. A population of birds separated by geography, breeding on a neighboring island, would adapt to the new environment by natural selection.

As the gene pools became distinct, interbreeding would eventually become impossible in a process that Mayr called “allopatric speciation.” Biologists accept allopatric speciation — from the Greek “allo,” for “other,” and “patric,” meaning “fatherland” — as the most common method by which new species arise.

Returning from his studies abroad, Mayr worked for 21 years as a curator at the American Museum of Natural History in New York. From New York, Mayr relocated to Cambridge, Mass., to fill the post of Alexander Agassiz Professor of Zoology at Harvard University until he retired in 1975. He was also the director of the university’s Museum of Comparative Zoology from 1961 to 1970.

Mayr had a prolific and distinguished career. He published more than 600 journal articles and authored or co-authored more than 20 books, beginning with Systematics and the Origin of Species in 1942 and ending with his latest work What Makes Biology Unique? published a month after his 100th birthday. Mayr won numerous awards, including the National Medal of Science in 1970. He also received the Balzan Prize, the International Prize for Biology and the Crafoord Prize, in 1983, 1994 and 1999, respectively.

Mayr was as intrigued by larger philosophical questions as he was by concrete, biological mechanisms. “Much as we know about the ‘how’ of human evolution, the ‘why’ is still a great puzzle,” Mayr wrote in 1963. Though an avowed atheist, Mayr said he believed a person could be deeply religious without the need for a personal God.

Mayr is survived by two daughters, five grandchildren and 10 great-grandchildren. His wife, Margarete, died in 1990.

Julia C. Keller is science editor at Science & Theology News.

Associated Press material was used in this report.