A typical day in the field in the dry savanna of East Africa ended up changing what scientists knew about early human evolution. As part of their research to understand and map fossils across an arid area of northern Ethiopia, a team of scientists found that what they were actually looking at was not just of geological significance but of immense significance for our evolutionary history.As investigators scanned the sun-baked ground, a small fossil fragment caught the eye of paleoanthropologist Donald Johanson.This little piece of bone became an important indicator for the researchers. Unlike a single tooth or jaw fragment a single tooth or pieces of jaws, the site eventually provided a partial skeleton that permitted scientists to examine the real body structure of an early relative of humans. The individual was found to be roughly 3.2 million years old, and she lived and died near the basin of an ancient lake, covered with layers of wet sediments. Rapid burial preserved the bones from any damage from either animals or weather, ensuring their preservation until erosion exposed them.Finding a critical link in the chain of evolutionThe findings of this specimen quickly changed the opinion of scientists about the timeline of human evolution since it gave direct physical proof of early upright walking. In accordance with the findings made by a team of scientists reported in the paper Limb Bone Structural Proportions and Locomotor Behavior in A.L. 288-1, the fossil specimen is dated to be nearly 3.2 million years old.Before the discovery of these data, there were many debates in anthropology regarding whether early human relatives started walking upright before or after they had bigger brains. However, the anatomical remains found at Hadar provided some insight into this long-lasting issue. According to Lucy's Story presented by the Arizona State University Institute of Human Origins, her pelvis and leg bones revealed that she had an upright bipedal posture despite her relatively small brain, which was similar in size to that of a chimpanzee. A single field moment that clarified locomotionThe fact that a significant portion of her anatomy is available presents us with a much clearer picture of how individuals belonging to the species Australopithecus afarensis would move around. The availability of both the upper and lower limb bone structures enables scientists to see how this individual would walk across open areas without giving up her ability to climb trees.In today’s day and age, the significance of the Hadar discovery is crucial when considering that science often reveals itself through one key observational moment in the field. The evidence obtained during the Hadar discovery in 1974 illustrates that being bipedal was a very early adaptation for our lineage and was achieved before our ancestors developed advanced tools. Human evolution involved slow and practical adaptations within Africa.However, the truth is that even as present-day travellers head to East Africa to marvel at its geographic marvels in the modern era, the proof of how we evolved millions of years ago was lying quietly beneath several inches of desert sand.