First 'Homo' species left Africa with ape-like brains

Given the "way" H. Sapiens is today, I surmise that the genus Homo evolved from A. Africanus, an upright, hands free, lethal weapon wielding ape. It's the use of lethal weapons and the consequences of such that made us "what we are" and gave us our brain development. It's Robert Ardrey's book "African Genesis" that shapes my opinion. Any alternative sources/fact based opinions would be appreciated. N.B.: In my opinion, our "agere sequitur esse" has an direct impact upon our future ability to colonize alien worlds, and more to reality, to exist on an over populated, resource depleted planet.