Final answer:
The discovery of Australopithecus afarensis, particularly the Lucy fossil, was significant for its completeness and for providing evidence of bipedalism in early hominins. It helped to bridge the gap between ancient apes and modern humans, representing a major step in the evolution of bipedal locomotion and an understanding of human ancestry.
Step-by-step explanation:
Significance of the Discovery of Australopithecus Afarensis:
The discovery of Australopithecus afarensis, best exemplified by the famous fossil named Lucy, has provided profound insights into early human evolution. Lucy's 3.24-million-year-old remains, discovered in the mid-1970s, represented a major leap in understanding human ancestors due to the completeness of her skeleton, which included 40 percent of her original structure. The significance of these fossils lies primarily in the evidence they provide for bipedal locomotion in early hominins, which was a pivotal evolutionary development. This species combined traits of both great apes and modern humans, displaying smaller canines and molars compared to apes, but larger than those of modern humans. The shape of the pelvis in A. afarensis suggests bipedal movement similar to that of modern humans.
The Australopithecus genus had various species, including Australopithecus africanus and Australopithecus sediba, each contributing pieces to the evolutionary puzzle. Australopithecus africanus, the first australopithecine discovered, provided further evidence for early bipedalism, while Australopithecus sediba offered complex traits indicative of both bipedalism and tree climbing. The genus ultimately played a crucial role in the transition towards genus Homo. The discovery of their fossils, along with footprint evidence from Laetoli, Tanzania, cements the importance of australopithecines in the hominin lineage.