The Butterfly Effect

The term 'butterfly effect' itself is related to the work of Edward Lorenz, based in Chaos Theory and sensitive dependence on initial conditions.

The 'Butterfly Effect' is the propensity of a system to be sensitive to initial conditions. Such systems over time become unpredictable, this idea gave rise to the notion that a butterfly's wings might create tiny changes in the atmosphere that may ultimately alter the path of a tornado or delay, accelerate or even prevent the occurrence of a tornado in a certain location. The flapping wing represents a small change in the initial condition of the system, which causes a chain of events leading to large-scale alterations of events. Had the butterfly not flapped its wings, the trajectory of the system might have been vastly different.

A great example of this theory was produced in this 2004 movie, 'The Butterfly Effect,' starring Ashton Kutcher, Amy Smart, and Eric Stoltz.