Let's get to human evolution. Today's topic will be the famous Australopithecus afarensis.
They had reduced canines and molars compared to other great apes, although still larger than humans. It appears they were in transition.
The curvature of the fingers and bones seem to be approaching modern-day apes, and seem well-suited for tree climbing.
They had a wrist locking mechanism, suggesting they could walk on their knuckles.
Scans of the skulls reveal a canal and bony labyrinth morphology that some suggest is not conducive to proper bipedal locomotion.
The pelvis, however, is far more human than ape like. The iliac blades are short and wide, the sacrum is wide and positioned directly behind the hip joint, and there is clear evidence of a strong attachment for the knee extensors.
Importantly, the femur also angles in towards the knee from the hip. This trait would have allowed the foot to have fallen closer to the midline of the body, and is a strong indication of habitual bipedal locomotion. However, one can still argue that that particular feature is also present in modern day Orangutans and Spider monkeys. There is a big problem with this, however. The feet. The feet also feature adducted big toes, making it difficult if not impossible to grasp branches with the hindlimbs. The loss of a grasping hindlimb also increases the risk of an infant being dropped or falling as primates typically hold onto their mothers as the mother goes about her daily business. Without the second set of grasping limbs the infant cannot maintain as strong a grip and likely had to be held with help from the mother. The problem of holding the infant would be multiplied if the mother also had to climb trees. The toes are all along the front of the feet, and not the sides, like tree climbing apes, which only serves to increase this problem. The ankle joint of A. afarensis is also markedly human-like.
AiG likes to use the fact that A. Afarensis has a very gorilla-like jaw, which one could see as a problem seei8ng as how gorillas branched off a good deal sooner than chimps and humans. However, thsi is only a problem for direct ancestry. Instead of Lucy being our "great-grandmother", it's more like our "great aunt". Since it is so obviously close to our direct ancestor, much data can be collected on what our direct ancestor was ike by studying it.