Don Johanson changed a great deal of what we know about evolution when he uncovered approximately 40% of the skeletal remains of one of the most complete early hominids in the fossil record. Hominids are the family of mankind and their ancestors. Johanson nicknamed his find “Lucy,” after “Lucy in the Sky with Diamonds,” a song by the Beatles.
Discovery in Ethiopia
Lucy lived about 3.2 million years ago. Scientists are unsure how she died, but her remains were quickly buried, which helped preserve her bones. In 1974, Johanson and his team discovered Lucy’s fossilized remains near Hadar in Ethiopia’s Afar region while excavating sediments that had once been part of an ancient lakebed.
What Made Lucy Special
Lucy’s brain was about one-third the size of the brain of a human, but Lucy had a human-like characteristic: her knee could lock, so she could stand up straight. Other apes did not have a locking knee, so they could not stand for long periods of time. Johanson deduced that the locking knee gave Lucy and others like her an advantage over other apes.
Changing Scientific Theories
Until Johanson’s find, archaeologists believed that apes grew smarter, then learned to walk upright. We now know that hominid brains grew larger only after they gained this small advantage over other animals. Don Johanson’s discovery of the remains of Lucy is an example of how scientific theories change over time.
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Mr. Donn has an excellent website that includes a section on Prehistory.