Ernst Mayr, Harvard University professor emeritus and biologist extraordinaire, died peacefully in Bedford, Massachusetts, on February 3. He was 100 years old and had been associated with the biology department at Harvard since he joined its faculty in 1953. An era in evolutionary thought, called variously the New Synthesis, neo-Darwinism or the Modern Synthesis, came to an end with his passing.

The death of the last of the great evolutionary biologists of the 20th century concluded an intellectual movement in the study of evolution—a point of view whose most striking aspect was the extent to which all of the evolutionary history of life on Earth was perceived as a subdiscipline of biology. Whereas Thomas Kuhn, author of The Structure of Scientific Revolutions, might have called it a paradigm, Ludwik Fleck (author of Genesis and Development of a Scientific Fact, 1935) would have recognized the correlated demise of neo-Darwinism and the death of Professor Mayr as a paradigm lost.

An accomplished naturalist, Ernst Mayr began his work in 1923 at the age of 19. The last of his 25 books, a collection of essays called What Makes Biology Unique? Considerations on the Autonomy of a Scientific Discipline, was published by Cambridge University Press in the summer of 2004, one month after his 100th birthday! This fact attests to Mayr's intellectual talents and unwavering interest in science, its history and philosophy.

And last May, shortly before Mayr's centenary birthday in July, an open celebration of his work and life was held in the auditorium of the Mineralogical and Geological Museum at Harvard. The place was crowded with admirers, spectators, students from universities and colleges from all over the Boston area and beyond. Several famous evolutionary biologists, colleagues, many of whom were among his former students and are now professional leaders, came to pay tribute. What struck me at this well-attended, enthusiastic gathering was that, among the marvelous lecturers in an all-day session about the evolutionary panorama of life on Earth, the most moving and informative of the talks, in my opinion, was the final statement by Ernst Mayr himself!

Mayr was born in Kempten, Germany (Bavaria), to an educated family, many of whom were physicians. His father, Otto Mayr, was a judge and a bird-watching enthusiast. During his school holidays Ernst worked at the Berlin Zoological Museum at the invitation of Erwin Stresemann, the best ornithologist in the country at that time. Following his two years of study at the University of Greifswald, oriented toward medicine as urged by his family, he completed his doctoral program in 16 months at the University of Berlin. Why did he opt to study at Greifswald? Why did he go north to a relatively unknown academic institution? Because his real interests were in the study of natural history, especially watching birds.