Dr. Ernst Mayr, the leading evolutionary biologist of the 20th century, died on Thursday in Bedford, Mass. He was 100.
Dr. Mayr's death, in a retirement community where he had lived since 1997, was announced by his family and Harvard, where he was a faculty member for many years.
He was known as an architect of the evolutionary or modern synthesis, an intellectual watershed when modern evolutionary biology was born. The synthesis, which has been described by Dr. Stephen Jay Gould of Harvard as "one of the half-dozen major scientific achievements in our century," revived Darwin's theories of evolution and reconciled them with new findings in laboratory genetics and in field work on animal populations and diversity.
One of Dr. Mayr's most significant contributions was his persuasive argument for the role of geography in the origin of new species, an idea that has won virtually universal acceptance among evolutionary theorists. He also established a philosophy of biology and founded the field of the history of biology.
"He was the Darwin of the 20th century, the defender of the faith," said Dr. Vassiliki Betty Smocovitis, a historian of science at the University of Florida in Gainesville.
In a career spanning eight decades, Dr. Mayr, the Alexander Agassiz Professor Emeritus of Zoology at Harvard, exerted a broad and powerful influence over the field of evolutionary biology. Prolific, opinionated and dynamic, Dr. Mayr had been a major figure and intellectual leader since the 1940's. Setting much of the conceptual agenda for the field, he put the focus just where Charles Darwin first placed it, on the question of how new species originate.
Though Dr. Mayr will be best remembered for his role as a synthesizer and promoter of evolutionary ideas, he was also an accomplished ornithologist. In fact, it was with the sighting of a pair of very unusual birds that Dr. Mayr's long career in biology began in 1923 at 19.