“Major transitions in evolution” is a term coined by John Maynard Smith and Eors Szathmary (The major transitions in evolution, Oxford University Press, 1997). The concept now has a substantial literature, a sample of which is represented on this forum.
Generally major transitions are thought to involve a population of small interacting entities that evolve ways to connect, enabling them to form a population of larger entities made up of various combinations of the small entities. The result is a complex ecology of both small and large entities, with complex interdependencies. The transition may also involve the evolution of mechanisms for information transfer and processing, and more generally, other new functionalities that may emerge in the transition.
The literature grapples with the question of how to define a major transition. Here (in this Projects category), the central question is empirical: how may a major transition be detected and observed in data produced by evolutionary dynamics?
A major transition in evolution may have the look and feel of a phase transition, or some other bifurcation phenomenon, but it is produced endogenously, that is, through the evolutionary dynamics, without manipulation of system parameters or meta-parameters (as a phase transition may be seen when temperature is manipulated). It is possible for a major transition to be connected to phase transitions or bifurcations, if an evolutionary model enables the evolving population to change the system’s own meta parameters (e.g. evolution of a mechanism to put mutation rate under genetic control).
Topics in this category should contain model simulations or data that display one or more major transitions, with clear indications for how the transitions may be characterized quantitatively.