Ernst Mayr — German Scientist born on July 05, 1904, died on February 03, 2005

Ernst Walter Mayr was one of the 20th century's leading evolutionary biologists. He was also a renowned taxonomist, tropical explorer, ornithologist, and historian of science. His work contributed to the conceptual revolution that led to the modern evolutionary synthesis of Mendelian genetics, systematics, and Darwinian evolution, and to the development of the biological species concept... (wikipedia)

In those early years in New York when I was a stranger in a big city, it was the companionship and later friendship which I was offered in the Linnean Society that was the most important thing in my life.
The major novelty of my theory was its claim that the most rapid evolutionary change does not occur in widespread, populous species, as claimed by Most geneticists, but in small founder populations.
According to the concept of transformational evolution, first clearly articulated by Lamarck, evolution consists of the gradual transformation of organisms from one condition of existence to another.
As a consequence, geneticists described evolution simply as a change in gene frequencies in populations, totally ignoring the fact that evolution consists of the two simultaneous but quite separate phenomena of adaptation and diversification.
It seems to me that for Darwin the pulsing of evolutionary rates was a strictly vertical phenomenon.