Ernst Mayr born July 5, 1904, Germany – February 3, 2005, 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.
No one else in his time knew the answer to the species problem: how multiple
species could evolve from a single common ancestor. Ernst Mayr started the
problem with a new definition for the concept of species. In his book
Systematics and the Origin of Species (1942) he stated that a species is not
just a group of similar individuals, but a group that can breed only among them,
excluding all others individually. Populations within a species become isolated by land,
feeding strategy, mate selection, or other means, they may start to differ from other
populations through genetic distinctions and natural selection which was his point to
prove the whole time, and over time may evolve into new species. The most significant and rapid genetic reorganization occurs in extremely small populations that have been isolated like on islands.
His theory of his work is primarily on birds, is still considered a leading mode of speciation, and was the theoretical
underpinning for the theory of punctuated equilibrium, proposed by Niles Eldredge and Stephen Jay Gould. Mayr is
sometimes said to have helped with inventing modern philosophy of biology, particularly the part related to evolutionary
biology, which he distinguished from physics due to its introduction of naturist history into science.