I am aware of the jaw evolution that caused our brain size to increase but I believe there are animals that have bigger brains than we do like extincted dinosouras. What I dont get is what makes one smarter than the other? How did we become the dominating species? How did we accelerate so much in science? Please try to answer quickly b/c I have an essay due on monday. I am not only talking about humans vs animals, but also talking about humans vs. humans. What makes one humans smarter than other? Although I know that there are several kinds of smartness, I am talking biologically. For instance, I know the bigger the brain is and the more oxygen a person gets, the smarter he becomes.