James Lovelock is the inventor of the idea of Gaia, which, in his own words, is "the hypothesis, the model, in which the earth's living matter, air, oceans and land surface form a complex system which can be seen as a single organism and which has the capacity to keep our planet a fit place for life". He was Born 1919 in Letchworth Garden City, UK. He graduated from Manchester University as a chemist, and taught at Baylor University College of Medicine in the US from 1961-64. He has worked independently and been a visiting professor at numerous universities. He is an independent scientist. Though fanatically accurate over details, he never isolates those details from a wider vision of their background. He thinks big. Preferring, as Darwin did, to work outside the boundaries of an idea, he has supported himself since 1963 through inventions and consultancies. Nurtured in Quakerism, he remains, in his eighties, quiet, vigorous, and intellectually articulate.
Lynn Margulis was born in Chicago on March 5, 1938. She graduated with an A.B. from the University of Chicago in 1957. She earned her M.S. in zoology and genetics from the University of Wisconsin at Madison in 1960 and her Ph.D. in genetics from the University of California, Berkeley, in 1965. She joined the biology department of Boston University in 1966 and taught there until 1988, when she was named distinguished university professor in the department of botany at the University of Massachusetts at Amherst. She retained that title when her affiliation at the university changed to the department of biology in 1993 and then to the department of geosciences in 1997. .
Throughout most of her career, Margulis was considered a radical by peers who pursued traditional Darwinian "survival of the fittest- approaches to biology. Her ideas, which focused on symbiosis, were frequently greeted with skepticism and even hostility. Among her most important work was the development of the serial endosymbiotic theory of the origin of cells, which posits that eukaryotic cells (cells with nuclei) evolved from the symbiotic merger of nonnucleated bacteria that had previously existed independently.