Final answer:
Australopithecus afarensis, or Lucy, was discovered by Donald Johanson in Ethiopia. Lucy lived around 3.75-2.8 million years ago and exhibited characteristics of both tree-dwelling and bipedal locomotion.
Step-by-step explanation:
Australopithecus afarensis, also known as Lucy, was discovered in the mid-1970s in the Afar region of Ethiopia by American paleoanthropologist Donald Johanson. Lucy's fossil was dated to around 3.75-2.8 million years ago. This species had a brain size similar to that of a modern chimpanzee and exhibited both tree-dwelling and bipedal locomotion.