I will present evolutionary game theory as a framework to model evolution, both social and biological, in which the basic properties that define complex systems can be studied, including the emergence of collective phenomena from the interaction of many lower level units. I will focus on some recent studies which introduced physical constraints in such framework, showing that the existence of a limited amount of energy or resources may trigger a self-organizing effect allowing for the evolution of cooperative behaviours €“which would otherwise extinguishâ“ and for the existence of a neutral evolutionary steady state out of equilibrium. To finish, I will discuss shortly the effect of destruction called the Joker effect on the evolution of altruistic behaviours.