Lynn Margulis (1938-2011)
Margulis was an evolutionary biologist who became famous for having been the first one to suggest that 3.5 billion years ago when there were only single-celled organisms without any complex internal structures, the symbiosis between creatures of different species accelerated evolution. The result was that eukaryotes were able to acquire their cell structures. Margulis argued that mitochondria, those cellular organelles that supply energy to the eukaryotic cell, were originally prokaryotes that symbiotically joined nucleated cells. She used to comment that 15 journals rejected her original paper before its publication in 1967, and it took more than a decade for her theory to be accepted by the scientific community.
She is also very well known for supporting James Lovelock’s Gaia hypothesis, which conceives the Earth’s biosphere as a system in homeostasis: a system in which variables are regulated so that internal conditions remain stable and relatively constant. According to Lovelock, the stability of temperature, ocean salinity, oxygen in the atmosphere, among other variables, is what acts to sustain life on the planet.