By the time of the great civilisations of Egypt, Greece and Rome, people lived a very different life. People had much more specialised roles in society, they found life easy enough to waste lives in wars, some of them could even write.
Some developments are more important than others.
These are the use of money, organised religion, the change in the art they produced. These things indicate a moving away from the oneness of earlier times. The god of the sun doesn't beam down sunlight from himself, he just rides a chariot through the sky, and the light comes from the shining wheels of the chariot. There are no gods of the tiger, or of the seagull, animals are seen as independent beings from the gods. More on this later.