Evolution and balance

Replica skulls of Australopithecus afarensis "Lucy" (3.6 - 2.9 million years old).
Homo habilis (2.33-1.6 million years).
Homo ergaster (1.9-1.6 million years).
Homo heidelbergensis (400,000-120,000 years).
Homo neanderthalensis (120,000-30,000 years).
Homo sapiens (125,000 years to the present day).