Australopithecus has a hunch and a small brain compared to modern day humans.
Homo erectus are more advanced (bigger brains) compared to Australopithecus and walks upright.
Homo sapiens are more advanced (brain size) and have a conscience.
Neandertal peoples think of reflective thought
Agriculture lead to an increase of population and the ability to stay in one area without hunting for food so cities formed.