I remember my mind being blown reading Douglass Hofstedler's essay in the mid eighties concerning strange attractors. You know, take two functions, plug the result of an operation from one into the variables of the second, then vice versa, over and over, plot the results. Sometimes, the graph of the results begin to orbit around certain values in unpredictable ways. Change the original values and the patterns change. This is the butterfly effect (which is a shitty metaphor, as popularized in Jurassic Park).

SA's are a great way of understanding how nature works. Take climate. We've some simple functions interacting and repeating, establishing a "normal" climate. Change the variables in those functions (like CO2) and new normals emerge. However, change them constantly, and you get lots of new normals. And lots of new normals eventually can be called chaos.