Final answer:
Lucy is known scientifically as Australopithecus afarensis, a specimen dating back to 3.8-3.0 million years ago and discovered in Ethiopia. The remains account for about 40 percent of an adult skeleton and have contributed greatly to the study of human evolution.
Step-by-step explanation:
The specimen found in Ethiopia/Tanzania that dates back to 3.8-3.0 million years ago and is more commonly known as Lucy is Australopithecus afarensis. Discovered by American paleoanthropologist Donald Johanson in 1973 in the Afar region of Ethiopia, Lucy's skeletal remains represent about 40 percent of an adult individual and have been a cornerstone in the study of human evolution. She demonstrates key evolutionary traits, such as bipedalism, and although she possessed a skull that resembled that of a chimpanzee, with a similarly sized brain, her upright walking stance places her closely on the human family tree.
Famous anthropologists like Richard and Mary Leakey have also worked extensively in the region, contributing to our understanding of early hominid species. The discovery of Lucy and other specimens of Australopithecus afarensis from across East Africa has provided invaluable insights into the physical and environmental challenges our ancestors faced and how these factors influenced the course of our evolutionary history.