Final answer:
Robert Broom discovered the first adult Australopithecus in 1938, which provided crucial evidence for the evolution of humans and supported the theory of natural selection proposed by Darwin and Wallace.
Step-by-step explanation:
Robert Broom, a South African paleontologist and physician, made significant discoveries concerning human evolution. In 1938, Broom found the first adult Australopithecus, which he named Australopithecus africanus. This discovery had profound implications for our understanding of human evolution because it provided the first evidence of an adult prehistoric hominid that showed both human and ape-like features. Broom's work supported the view that humans evolved in Africa and were more ancient than previously thought, which challenged the earlier prevailing idea that humans had evolved in Asia or Europe.
Understanding Broom's findings in the context of evolution shows how the discovery of Australopithecus africanus contributed to the accumulation of evidence for the theory of evolution. These findings supported the ideas of Charles Darwin and Alfred Russel Wallace on natural selection as the mechanism of evolution. It demonstrated that human evolution was indeed a gradual process marked by significant transitional forms, which was consistent with the principles of evolution that Darwin and others had proposed.