Sapiens: A Brief History of Humankind
Animals much like modern humans (Yuval is going to refer as the genus Homo) first appeared about 2.5 million years ago, but they didn't stand out from other organisms. Prehistoric humans were insignificant animals compared with others, every specie had the same significance.
Homo sapiens (denoted as Sapiens), our specie, divided the Earth with many others human species, like Homo rudolfensis, Homo erectus, and Homo neanderthalensis from about 2 million years ago until around 10,000 years ago.
The biggest difference between humans and other animals is the size of the brain. But the size of the brain has its evolutionary costs. It's not easy to carry around and consumes a lot of energy. Archaic humans paid this cost by spending more time in search of food and having their muscles atrophied. It wasn't a good strategy for survival in savannah.
Another difference is that we walk on two legs. The advantages is that was easier to scan the savannah for game or enemies, and arms was freed for other purposes, like throwing stones. The evolutionary pressure increased the concentration of nerves and finely tuned muscles in the palms and fingers.