The German-born American evolutionary biologist Ernst Mayr (born 1904) helped lead the modern synthesis of evolutionary theory. Mayr made major contributions to ornithology, evolutionary theory and the history and philosophy of biology. He is best known for his work on speciation--how one species arises from another.

Ernst Mayr was born in Kepten Germany, near the borders of Austria and Switzerland on July 5, 1904. He was one of three sons of Helene Pusinelli Mayr and Otto Mayr, who was a judge. The Mayr family valued education and Mayr and his brothers were provided with a broad education that included the study of Latin and Greek. All three sons became professionals. As a boy, Mayr developed a keen interest in birdwatching--an interest that remained with him for life. Mayr began to study medicine in 1923 at the University of Greifswald, but within two years he became so enthralled with the evolutionary works and...