Only parts of the world not populated were the extremes: desert, arctic, Cuts off eastern asia where there are no handaxes, only oldowan tools. Potential issue with dating or contamination by ergaster/erectus (maybe. Boats or fluctuating environments causing a land bridge or the ability to swim across. Some call them homo antecessor because they think they"re too advanced to be ergaster or erectus. What is now sahara and most of the. Middle east would have been in times of warmth would have been grasslands. When dryness comes about, loss of grasslands would have forced the herds out of the desert, and ergaster followed. Allows for social interaction, not waking and sleeping with the sun. Time when you"re not dealing primarily with survival. Overlap of h. habilis and h. rudolfensis of 1. 5my. Rudolfensis more human like, especially in body plan. Still have thicker teeth, jaws, etc. compared to humans and archaic homo.