Final answer:
The fossils suggest a new stage of human evolution emerged with Homo erectus in Africa after 2.5 mya, following earlier hominins like Australopithecus.
Step-by-step explanation:
The fossils from Homo erectus imply that a new grade of human evolution appeared in Africa not long after 2.5 million years ago (mya). Early hominins like Australopithecus, which evolved approximately four million years ago, represent an earlier stage prior to the genus Homo. The first appearance of Homo species signifies a significant step in human evolution, with Homo habilis, identified by stone tools and a larger brain, highlighting new adaptive strategies that would eventually lead to modern Homo sapiens.