Lucy: The Drastic Change

of Human Evolution

By: Emily Eade

The year was 1974, we saw the demise of one of the greatest bands of all time, The Beatles. This same year, one of the greatest discoveries of human evolution was made. Little did you know, there would be a connection between the two.

This is the story of Lucy, known scientifically as Australopithecus afarensis, and how she changed the course of human evolution…

Paleoanthropologist Dr. Donald Johanson and a group of researchers from the Cleveland Museum of Natural History were in the dry, arid land of Ethiopia, specifically, the Afar region. Throughout the long days in the sweltering heat, the researchers would have fun listening to “Lucy in the Sky with Diamonds” on repeat too many times to count and digging in the dirt, hoping that they’d make a great discovery… and that they did.

On November 24, 1974, Johanson and his student Tom Gray would take a Land Rover out for the day looking for new sites to explore. After a long, hot morning venturing out, they decided to go back to the Land Rover but would take a different route. Within a short period, Johanson would spot a right proximal ulna, a forearm bone, which would quickly be identified as a hominid, a family of primates that include humans and their fossil ancestors. Quickly after, Johanson would find an occipital bone (skull), a femur, some ribs, a pelvis, and a lower jaw. Two weeks later, after the many hours spent digging and sorting through hundreds of fragments of bone found, only 47 of them would form a small fossil skeleton.

After finding about 40% of this skeleton, the remains were brought to geochronologist, Dr. James Aronson, who would start the process of potassium-argon dating. This is a method of determining the time of origin of rocks found around the area of this discovery, by measuring the ratio of radioactive argon to radioactive potassium found in these rocks. However, there was a delay in finding the age due to obstructions such as rocks being chemically altered by volcanic activity and the lack of pumice clasts. They eventually concluded that Lucy was 3.2 million years old.

The remains were also analyzed by anthropologist and anatomist, Dr. C. Owen Lovejoy. Throughout his research, Lovejoy would notice things such as, the skull being rounder and a sciatic notch of greater than 90 degrees, with these observations Lovejoy concluded that this skeleton was most likely a female. He would also notice that there is a femoral angle, making her a bipedal hominid, unlike older discoveries she would walk on two legs instead of four.

This skeleton would become one of the most famous discoveries of all time. She would be named Lucy, after the Beatles hit, “Lucy in the Sky with Diamonds,” which was played on repeat at the campsite. Lucy would change the trajectory of human evolution. Not only was she one of the earliest found remains, but she was also the first bipedal hominid. She showed us the evolution of mankind. This year marks 50 years of Lucy and her significance to who we are today.