Final answer:
According to Johanson and White, Australopithecus is considered the last common ancestor of A. boisei and H. habilis. The relationship between these hominins represents a critical part of human evolutionary studies, highlighting both their unique features and the ongoing debates regarding their place in our lineage.
Step-by-step explanation:
According to Johanson and White, Australopithecus was the last common ancestor of A. boisei and H. habilis. These species are part of a complex tree of human evolution, with H. habilis often considered one of the earliest members of the genus Homo. However, there has been much debate regarding its exact place within the hominin phylogeny, particularly in relation to it being a direct ancestor or a cousin to other Homo species.
Paranthropus boisei and H. habilis are both important to our understanding of human evolution. For instance, Paranthropus boisei was a robust species found by Louis Leakey and Mary Leakey, noted for its powerful jaw muscles and large molars. On the other hand, H. habilis, with smaller teeth and evidence of tool use, has features aligning it closer to modern humans and marking important evolutionary developments.
The lineage debate highlights the challenges in paleoanthropology, where new discoveries can challenge existing theories and suggest new relationships amongst early human ancestors. Thus, the lineage from Australopithecus to species like H. habilis and Paranthropus continues to be an area of active research and discussion.