Is MMA the exact same fighting style as Vale Tudo, or are they different?

After reading up on it, I find it hard to differentiate the two as separate fighting styles. They both use a combination of all different martial arts. I can see how they d be viewed as two separate sports, since they have different rules, but as a fighting style are they both the same? Was it only after the UFC started that fighters began to combine fighting styles into a single style, or were they doing that years prior in Vale Tudo tournaments?