Our feet are the most evolved, or derived, from the common ancestral form. Many people assume it's the human hand, but they are almost identical to those of our closet living relatives, the African apes. But if you compare our feet to those of gorillas and chimpanzees there are big differences. The main one is that we have lost the ability to oppose the big toe with the other toes, ie we can't touch our little toes with the big one in the same way we can with our thumb and fingers.