One can argue that the American Revolution was both a revolution as well as an evolutionary period. It served as a revolution because it fundamentally changed the nature of power in the new world. It was revolutionary in how the Colonists broke free from England. It was revolutionary in the manner of how victory was achieved. A group of freedom fighters were able to defeat one of the most dominant armies in the world. The "New World" was able to establish its own leadership and was able to emerge from the shadows of being colonies and embraced the idea of being its own nation. The Revolution aspect was one in which power shifted and a sense of identity emerged. It was a revolution how it fundamentally changed what was into something previously unthinkable.
In many respects, the American Revolution can also be seen as a step in the political evolution process. This is seen in how democratic notions of the good became something understood throughout the world. The French Revolution borrows the same egalitarian spirit of political orders as the animating force behind its revolution. The Latin American Wars of independence were inspired to a great extent by the American Revolution and the change that it offered. The American Revolution could be seen as a step in the evolutionary process through which the liberally democratic orders emphasized egalitarianism within political structures in the modern setting.