50 years ago researchers working in the Afar region of Ethiopia recovered a remarkable fossil of one of our ancient relatives. This specimen, or member, of a female hominid human familyit soon became the most famous fossil in the world. If you’ve ever had even a passing interest in human origins, you’ve probably heard about it. It goes by the name Lucy.
One of the reasons Lucy is special is that she has a recognizable, albeit incomplete, skeleton. Another is that the skeleton is similar enough to ours for researchers to think that it may be similar to Lucy, and possibly an ancestor. modern humans. But Lucy is just one of them many hominin fossils which have since come to light Charles Darwin In 1871 he believed that humans originated in Africa. Why does it play such an enormous role in the public imagination—and in the study of human origins? The answer lies in Lucy’s value as a symbol of humanity’s deep African evolutionary history, as well as in her intrinsic value as a source of evidence for human evolution.
Let’s go back to Lucy’s time. Almost 3.2 million years ago a small human ancestor with a mixture of human and ape characteristics lived in a grassland landscape dotted with trees and shrubs in the Horn of Africa. It was part of a much richer primate community and a much more impressive variety of mammals that inhabit the region today. There is no reason to think that Lucy was anything special in her relatively short life. What made him special was what happened to him after his death.
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When an animal dies in an open landscape, far from lake shores or stream channels, the soft tissues—muscles and ligaments—are consumed by scavengers large and small. The bones of the skeleton soon separate and break, and in an incredibly short time, only fragments of the skeleton remain. There is nothing recognizable fossilized. If the animal dies close enough to a lake or stream, there is a very small chance that one or more of its bones and teeth will be covered by a layer of sediment. The bones will not only physically protect the sediments from further damage, but under the right conditions, the chemicals in the sediments will harden them. This process, called fossilization, gradually transforms bones and teeth into bone- and tooth-like rocks.
But if all that happens, we are still far from the remains of that individual becoming a famous fossil. To do this, the sedimentary rock in which the bones are buried must be exposed due to erosion, a team of scientists and trained fossil hunters must find the fossilized bones before they are destroyed, and the team must have the necessary extensive resources. elements to recover numerous pieces of grain scattered across the landscape. The extremely small chance of preserving, fossilizing, exposing, finding and recovering the bones and teeth of a single individual makes the Lucy skeleton an extraordinary find. In the early stages of the human fossil record the number of such skeletons can be counted on the fingers of one hand.
Another reason Lucy is exceptional is that among the various regions of her skeleton that are preserved are large portions of bones that show the length of the limb: the humerus and radius in the upper limb and the femur and tibia in the lower limb. One of the biggest differences between modern humans and our closest living relatives, chimpanzees and bonobos, is relative limb length. While modern humans have long legs and short arms, chimpanzees and bonobos have long arms and short legs. Chimpanzees and bonobos also have relatively long forearms.
The four long bones of Lucy’s main limb have parts of the shaft damaged or missing, so their maximum length must be estimated. However, enough of each bone is preserved to make Lucy’s limb proportions, and thus limb proportions, fairly clear. Australopithecus afarensis, his own species—they are closer to chimpanzees and bonobos than to modern humans. This does not mean that Lucy moved like a chimpanzee or a bonobo: other fossils. A. afarensis provide convincing evidence that the species walked upright on two legs. But he was practicing bipedalism that differed significantly from the bipedalism used by modern humans and our immediate predecessors. We, on the other hand Wise man when we take long steps when we walk, A. afarensis he walked more slowly because his feet were further apart.
Some experts believe that Lucy is in the line leading to modern humans, adding to her cache. But proving ancestry is difficult and almost impossible to prove with the patchwork fossil record we have for early hominins. I know the difference between my ancestors—parents, grandparents, and great-grandparents—and my ancestors’ immediate family members, such as aunts and uncles, and if I wasn’t sure of someone’s status, I could check using their birth certificate. There is no birth record in the fossil record, so we have to use shared morphology. The principle is that the more physical characteristics one species shares with another, the more closely related the species will be, assuming that the morphology they share evolved only once in the last common ancestor of the two species. We call this commonality shared derived morphology. But to go back to my family history, although I look more like my parents than a complete stranger, after going back several generations, my resemblance to my ancestors is less obvious.
The fly in the ointment when using shared morphology to reconstruct relationships is a phenomenon known as homoplasy, in which different lineages evolve shared morphology independently rather than inheriting it from a common ancestor. In this case, shared morphology is telling us more about shared environmental challenges than shared evolutionary history. However, even though A. afarensis it is not our ancestor, it is very likely that it is a close relative.
Lucy was discovered in 1974, nearly half a century after anatomist and anthropologist Raymond Dart recognized the significance of a young hominin skull found in Taung, South Africa. For three decades after the discovery of young Taung, the search for human origins focused on southern Africa. This focus was changed in the 1960s by Louis and paleoanthropologists Mary Leakey began to find hominin fossils Olduvai (now Oldupai) Arroila, Tanzania, some of them looked like they might even be of our genus, Homo. By 1974, the flood of fossil discoveries in East Africa had become insular, with most discoveries coming from sites along the now known east coast. Lake Turkana.
Not only did paleoanthropologists focus on southern and eastern Africa, but the age profile of the most successful fossil hunters was changing from leading researchers to field workers such as Louis and Mary Leakey, Phillip Tobias, and Clark Howell. Richard Leakey and Donald Johanson, who were younger than Dart when he recognized the importance of the Taung skull. Richard Leakey and Johanson were half their predecessors’ age, and telegenic. Any high school or college student interested in human origins could imagine himself in his place.
Lucy’s discoverer, Johanson, had the great idea to name the partial skeleton after a character from the popular Beatles song “Lucy in the Sky with Diamonds”. Lucy O’Donnell was a childhood friend of John Lennon’s son, Julian Lennon, and one day she brought home a drawing from school and said it was Lucy in the sky with diamonds, which inspired the song. “Lucy” was a nice way to refer to the name A. afarensis The skeleton had the official catalog AL 288-1. And teaming up with O’Donnell injected vibrancy and relatability into a bone-chilling collection of rock.
But a lot has changed since Lucy was named in the mid-1970s. On the one hand, scientists today are aware of the implications of the names given to fossils. Like John Lennon, Lucy O’Donnell was from Liverpool, England. Much of the Beatles’ success was based on its members’ authenticity as Liverpudlians. At the time of the Beatles, Liverpool was in economic decline, but in the 18th century In its heyday in the 19th century, the main port of the United Kingdom, the economic basis of Liverpool’s prosperity came from the leading role played by its merchants in the African slave trade. the people
The Lucy fossil has another nickname. In Ethiopia he is known as Dinkinesh, which means “you are wonderful” in one of the country’s official languages, Amharic. As iconic as the name Lucy is, maybe it’s time we all start using Dinkinesh to refer to this extraordinary member of the human family.
