Abstract
The conception of symbiosis as biological interactions between different species is well established in contemporary biology since its introducing in late 19th century by A. de Bary. However, to date, symbiosis is primarily understood to be an ecological concept despite of its "Janus" face in form of the evolutionary importance of the phenomenon.
In 1909, K. Merezhkovsky coined the term symbiogenesis for expression the fact that new species can arise throughout symbiosis, and much more later, in the scond half of the twentieth century, L.
Margulis has shown that symbiosis is a crucial aspect of process of evolution. I argue here that there is yet another facet of the term, which results from the previous, but yet it is autonomous: symbiosis as a universal model for theoretical biology.