The sequence of being hunched over as a shuffling apeman in the middle to an erect man at the end is also wrong. Bipedality came early in hominin evolution, and is linked with an upright skeletal frame, not some missing link that mixes chimp and human into one. Finally, the linear sequence itself is wrong. There were numerous species of hominins in the past, a veritable branching tree just like Darwin used to diagram.
Shea adds one more important element that helps to completely dismantle this popular image. We often assume that our immediate ancestors were primitive, and that something special must set us apart.