Why are the discoveries of the Leakey's and Donald Johnson considered important?

The discoveries of the Leakey's and Donald Johnson are important because they have significantly advanced our understanding of human evolution. Their findings, such as the Australopithecus and Homo fossils, have provided crucial insights into the origins and development of the human species. These discoveries have helped piece together the evolutionary timeline of early hominins and shed light on our shared ancestry with other primates.