Main physical evolution from homo habilis through Homo sapiens is increasing complexity and size of brain . Bigger brain is selected for because humans have language and culture, and bigger brain is more skillful at mating culture and childcare . Bigger brain type population grows because it is having more sexual intercourse. 凸

@charlesbrown1365 • 3 min ago With cooking food, the teeth can be smaller, so there is more room for bigger brain in the skull.

Language starts with homo habilis. We know this because the Stone Age stone tools were made by design, in styles. Only with language, symbolic communication can a maker design a tool. Chimps and gorillas have communication but not symbolic communication. They don't have past or future tense, because they don't have displacement. They don't ask questions, even when trained for years. Displacement was the key to humans' superior Darwinian fitness, that is population growth. 凸⑦回 @charlesbrown1365 • 1 min ago