There are diferences, but in a large part much of what we do is simular, reguardless if we are standing up or on the ground. We are a small circle principal, but with some technoques especialy on the groung you can't do much in that area. This is when we focus on breathing and joints. If I'm on my back and someone has mounted me, with their hands on my throat then one of the first things I'm going to do is reach over and do a cross side wrist grab and then an elbow strike of some kind. As soon as I strike I will roll my body to help with the momentum in getting the guy off of me. With their elbow in pain I can then go for one of many joint locks or a nice arm bar with little or no resistance.
In the end the outcome can be the same as in Ju jitsu, but how we get there can be the biggest diference. But still many simularities do abound. Hope this helps.