Significance of Lucy’s Discovery in Human Evolution
Humans evolved from their ancestors over the past 2,00,000 years. It is always a curiosity to find from which ancestor we evolved. With the help of palaeontology, we can now study ancestral fossils and their origin.
Australopithecus is a group of primates related to the ancestors of humans. They were known from fossils found at various sites in eastern, north-central, and southern Africa. Various species lived around 4.4 million to 1.4 million years ago.
The Story of Lucy
On November 24, 1974, at the site of Hadar in Ethiopia, Donald Johanson and Tom Gray took a land rover to map another locality. After long hot surveying and mapping of fossils, they decided to head back to the vehicle. Instead of taking the same route, Johansen suggested taking an alternate route through a gully.
He spotted a right proximal ulna within moments and quickly identified that it was a hominid. A hominid is a member of the family Hominidae, which includes humans, gorillas, and chimpanzees. Within no time, he saw a skull, femur, some ribs, a pelvis, and a lower jaw. After many hours of screening and sorting, and excavation, about a hundred other fragments of bone were recovered, representing 40 per cent of a single hominid skeleton.
On 24th November, late in the night, when everyone was excited and celebrating the discovery of a complete hominid skeleton, they were singing and dancing to the song Lucy in the sky With Diamonds by The Beatles, the song kept repeating, and later in the night, no one remembered who named the skeleton Lucy.
Lucy’s Gender and Age
Lucy was identified as a female because of her small size.
He knew that, like many living primates, the hominins male were bigger than the females.
They estimated her height based on the length of her femur and also on the mathematical formulas used to measure her stature based on the femur length. Her height was estimated around 104 to 106 cm tall.
Her wisdom teeth indicated that she was a fully grown adult because they erupted and were slightly torn.
Her cranial sutures were also closed, and her bones were fused, which indicates her complete skeletal development.
All of these indicate that she was a young, fully grown adult when she died.
Lucy Death
How Lucy died was a big question for the palaeontologists when they discovered her.
Earlier, when Lucy was discovered, no cause was determined as such. There were clues suggesting the lack of postmortem carnivores and scavenger marks.
The tooth puncture mark on the top of her left pubic bone was the only damage seen on Lucy’s bones. This injury happened during the time of death.
After forty-two years of her discovery, a new analysis suggests that Lucy’s death was caused due to the fall from the tree.
Predators like hyenas and jackals would have caused a threat to her. So she turned to the trees to escape from them. An average of 46 feet from the ground makes them feel safe.
Lucy was either frightened by the predator, or she was asleep for the night.
She was fully conscious when she fell from the tree at the speed of 35mph.
Her feet hit first on the ground, and an impact sent through her body that fractured her ankles, knees, hip, and shoulder.
In order to prevent the fall, Lucy put out her arms forward, creating fractures in the bones.
While landing, she must have twisted on her right side, fracturing her neck and head. At this time, she was unconscious and laying on the ground.
The water must have moved her body a short distance carrying her to the final place.
The Fossil of Lucy
Johanson and Gray determined that the fossil belongs to only one hominid skeleton by the number of bone fragments they collected. If there were more fossil fragments, it could have indicated the presence of more than one individual.
The elbow region of her ulna was the first fragment that Johanson discovered.
They carefully searched the ground and were stunned to discover many more fossilised bone fragments such as cranium, ribs, pelvis, thigh, feet, mandible, and many more.
Lucy’s bones are filled with evidence clearly indicating bipedality. Bipedality can be seen by the arrangement of her bones like how her distal femur is showing several traits of bipedality, shaft is angled to the condyles allowing the bipeds to balance on one leg at a time during the movement.
A patellar lip keeps the kneecap from dislocation; condyles are large and thus can balance the added weight that results when we shift four limbs to two.
The pelvis and the talus in her ankle also show adaptations to bipedality.
Australopithecus Characteristics
Australopithecus is a combination of both apelike and humanlike traits, and they are the closest known to modern humans.
They were bipedal like modern humans but had small brains like apes.
Their cheek teeth were larger than humans, and their canine teeth were smaller than apes.
Australopith is a term used to refer to the members of the genus Australopithecus.
Australopithecines include the genus Paranthropus, which combines three species together called the robust.
Australopithecus contains different hominin species that lived for about 4.18 to 2 million years. Currently, there are eight different species that are found in the genus Australopithecus, which include Australopithecus africanus, Australopithecus afarensis, Australopithecus sediba, Australopithecus Garhi, Australopithecus anamensis, Australopithecus deyiremeda, Australopithecus bahrelghazali.
Interesting Facts
Australopithecus is capable of upright walking, but they are not well adapted for travelling long distances on the ground.
Australopithecus means southern ape and is referred to as the species of South Africa.
Australopithecus is also known as an extinct African hominid.
Key Features
Lucy possessed a unique feature from other species, which is she had a valgus knee which indicated that she moved normally by walking upright.
Her femur is a mix of ancestral and derived traits, and both are primitive traits.
Lucy was the oldest and most complete hominid palaeontologist ever discovered.
FAQs on Lucy the First Human: Evolution’s Game Changer
1. What is 'Lucy' and who discovered her?
'Lucy' is the popular name given to the fossil skeleton of a female from the species Australopithecus afarensis. She lived about 3.2 million years ago and was discovered in 1974 in Ethiopia by a team of paleoanthropologists led by Donald Johanson.
2. How did Lucy get her famous name?
The discovery team was celebrating at their campsite and repeatedly playing The Beatles' song "Lucy in the Sky with Diamonds". Inspired by the song, one of the team members suggested the name 'Lucy', and it became the official nickname for the fossil skeleton.
3. How old was Lucy when she died and how do we know?
Scientists estimate Lucy was a young adult when she died. They determined this by studying her bones and teeth. For example:
- Her third molar, or wisdom tooth, had emerged, which is a sign of adulthood in hominins.
- The growth plates in her bones were fused, indicating that she had finished growing.
4. Where are Lucy's fossil remains kept today?
The original, real fossil bones of Lucy are carefully stored at the National Museum of Ethiopia in Addis Ababa. To allow people around the world to study and see her, high-quality replicas have been made and are displayed in many museums.
5. What did Lucy look like compared to a modern human?
Lucy was much smaller than modern humans. She stood about 3.7 feet (1.1 meters) tall and weighed around 29 kilograms. She had a mix of features: a small, ape-like head and long arms suitable for climbing, but her hip and leg bones clearly show she walked upright on two legs.
6. Was Lucy actually the first human?
No, Lucy was not a human in the modern sense (Homo sapiens). She belonged to an earlier, ancestral species called Australopithecus afarensis. She is a very important hominin—a member of the evolutionary group that includes modern humans—but the first members of our own genus, Homo, appeared much later in the fossil record.
7. Why is Lucy's discovery so important for understanding human evolution?
Lucy's discovery was groundbreaking because her skeleton was remarkably complete. It provided the first definitive proof that our ancient ancestors were walking upright on two legs (a trait known as bipedalism) long before their brains became significantly larger. This discovery fundamentally changed our understanding of the sequence of human evolution.
8. What is the main difference between how Lucy walked and how we walk?
The main difference is in efficiency and adaptation. While Lucy was fully bipedal, her skeleton suggests her gait might have been slightly different from ours. Her long arms and curved fingers also indicate she was likely still skilled at climbing trees, perhaps for safety or to find food. Modern humans are adapted for walking and running long distances on the ground and have lost those climbing adaptations.
9. What does Lucy’s skeleton tell us about how early hominins lived?
Lucy’s skeleton provides key insights into the life of early hominins. Her ability to walk upright suggests she lived in an environment like a savanna or woodland where moving on the ground was beneficial. However, her ape-like upper body features suggest that trees were still an important part of her habitat, likely used for shelter from predators and for sleeping at night. This shows a transitional lifestyle between the trees and the ground.
10. If older hominin fossils have been found, why is Lucy still so famous?
While older hominin fossils like 'Ardi' do exist, Lucy remains famous primarily because of the completeness of her skeleton. At 40% complete, she provided a much clearer picture of what an entire ancient ancestor looked like and how it moved. This completeness made her a powerful symbol for human evolution that was easy for both scientists and the public to understand.
