Part 2/10:
As a starting point, it is essential to understand that all hominins, including Australopithecus, are characterized by their obligate bipedal locomotion. This adaptation is defined by a suite of morphological traits collectively necessitating upright walking. Key features include the anterior placement of the foramen magnum (the opening at the skull base), valgus knee (a knee angled inward to support upright posture), a bowl-shaped pelvis with anteriorly oriented iliac blades, foot arches, and an inline hallux (big toe aligned with other toes).
These traits paint a picture of hominins well-suited for terrestrial bipedalism, a hallmark of their evolutionary trajectory.