We humans if not inventions. Our innovations have permeated almost every aspect of our daily lives, from the way we eat to the way we communicate. This ingenuity is naturally linked to our large brains and our hands, which are very dexterous compared to those of other primates. Paleoanthropologists have long sought it the origin of human technological innovation. The famous Lucy the fossilThe discovery 50 years ago this month brought a new understanding of this hallmark of humanity.
In the 1950s the English paleoanthropologist Kenneth Oakley emphasized tool making as a uniquely human trait because, unlike, say, language, it could be demonstrated through archaeological evidence. The use of the tool and, in particular, the tooldoing According to Oakley, they were considered distinct human abilities that probably began with the big-brained ancestor. Pithecanthropus erectus, today The man stood up.
In the 1960s, after pioneering primatological research in the Tanzanian jungle, Jane Goodall showed the world that chimpanzees in what is now Tanzania’s Gombe Stream National Park used sticks to fish for termites and ants and also used leaves as drinking implements. Although Charles Darwin had noted nearly 100 years earlier that “the chimpanzee in a state of nature cracks a native fruit, like a nut, with a stone,” Goodall was the first to properly document chimpanzees modifying organic tools and gaining access to them. to otherwise inaccessible resources. This revelation prompted Kenyan paleoanthropologist Louis Leakey to say, “We must now redefine the tool, redefine man, or accept chimpanzees as human.”
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However, the idea that humans were the only true toolmakers persisted for a little longer, with proponents arguing that only humans and their ancestors were the same species. Homo uses tools regularly and to a high standard. In fact, around the same time Goodall announced his findings, Leakey and his colleagues defined a new species of fossil human…A handyman meaning “useful human” or “skilled human”—not unlike the supposed ability of the creature based on the Oldupai (ancient Olduvai) canyon in Tanzania to make tools with stone. organic tools made by chimpanzees. Louis and Mary Leakey found new fossils associated with stone tools, and skull bones indicated a larger brain than older hominins (members of the human family). Additionally, several hand bones were interpreted to reflect the skill required to make stone tools. Since stone tool-making was characteristic of humans, Leakey insisted that these new fossils must belong to a member of our genus. Homo.
The Oldupai discoveries dominated scientists’ understanding of early hominin hand and tool behavior for decades. When it was known as a partial skeleton of a 3.2 million year old human ancestor Lucy Discovered in November 1974, at first no one thought they had made or used stone tools. This may be partly because Lucy’s skeleton preserved only two hand bones: a bone in the middle of the wrist, called the capitate, and a finger bone called the proximal phalanx. But the following year’s discovery of fossils of Lucy’s species at the nearby AL 333 site—a discovery that included numerous hand bones—didn’t spark a debate about the tool’s behavior. Australopithecus afarensis, Lucy’s species. Other than stone tool technology, it was still unique Homobut also, at 3.2 million years old, Lucy was 1.5 million years older than the oldest stone tools known at the time.
In 1983 the late anthropologist Mary Marzke was the first to offer a functional interpretation of the morphology of Lucy’s hand bones and those found at the AL 333 site. His pioneering work highlighted a mixture of human-like features, such as a relatively long thumb and short fingers, and ape-like features, such as limited mobility of the little finger and curved finger bones. Marzke inferred from the morphology of the hand bones the types of grips that Lucy and her ilk might have used, such as pad-side grips, which we use when we turn a key in a lock, and three-digit grips, which we use. when we throw a baseball. Marzke suggested that, using these handles, A. afarensis it can manipulate stone tools to hammer animal bones to extract the nutrient-rich marrow inside and slice flesh with stone flakes. But despite Marzke’s interpretation, scientists generally held to the idea that stone tool behaviors arose only with gender. Homo.
Marzke was very ahead of his time. We would have to wait nearly 20 years for archaeological evidence of the behaviors he inferred from hand morphology. A. afarensis. It was discovered by researchers in 2010 evidence of hammering (or percussion) and cut marks on animal bones A. afarensis the site minutes In Ethiopia, dated to 3.4 million years ago. Five years later another group presented large, crude stone tools, representing a previously unknown technology, from the site of Lomekwi in Kenya, 3.3 million years ago. These finds provided the first evidence of stone tool manufacture at the time A. afarensis.
The idea that Lucy can and probably does use stone tools is more supportive of everything we’ve learned nonhuman primate tool use from his discovery. In the early 1980s, building on Goodall’s work, two primatologists, the late Hedwige Boesch-Achermann and the late Christophe Boesch, documented chimpanzees cracking nuts with stone and wooden hammers in Ivory Coast’s Taï National Park. Today, archaeological evidence suggests that Taï chimpanzees have been cracking nuts with tools for at least 4,000 years. It is also clear that there are many cultural variations in how different chimpanzee communities perceive termites to eat nuts or fish. In addition, chimpanzees living in the savannah create and use wooden spears to hunt other primates. Capuchin monkeys can use stone hammers that are almost half their body weight to crack nuts. And long-tailed macaques use stones to open oysters. These monkeys can do it too unintentionally creates stone flakes which look identical to those found in the archeological record of hominins from two million years ago.
Studies of other primates have shown that various hand morphologies—not just those of humans—are capable of highly dexterous behaviors. The human thumb is considered integral to our dexterity. It is long compared to the length of our fingers; it is strong, and is attached to two additional muscles not normally found in other primates. And it has a wide, saddle-shaped joint on the wrist that allows the knuckle of the thumb to easily oppose the pad of each finger in what we call a “strong precision grip.” Researchers have generally believed that these grips are unique to humans. But while our opposable thumb is essential in our daily manipulative activities (try writing with a pen or using a screwdriver without it), it’s not just for humans; All monkeys and apes living in Africa and Asia, as well as some living in South America, have opposable thumbs. The long, curved fingers of the chimpanzee hand and the less mobile and weaker thumbs of some monkeys are also capable of producing powerful pad-to-pad precision grips. Gelada baboons and chimpanzees use these handles to remove grass; macaques use stone hammers to break shellfish and oysters. Precision skills are also central to many other primate behaviors, such as processing plant foods and grooming.
Evidence from living primates suggests that skill in tool use and precision is probably not a trait A. afarensis but also all earlier hominins. Given that all great apes (chimpanzees, bonobos, gorillas, and orangutans) are skilled tool users in zoos, if not in the wild, it is likely that the last common ancestor of all great apes is accurate to about 13 million years ago. skill and tools used. However, we face two major obstacles to testing this hypothesis and determining when, why, and in which species tool use and manual dexterity evolved.
The first hurdle is the lack of a fossil record of African apes, meaning we know nothing about how their bone morphology evolved over millions of years. This makes it very difficult to reconstruct what the last common ancestor’s hand might have looked like, and therefore what selective pressures ultimately led to the hand morphology we see. A. afarensis. Did the early hominin hand evolve from something that looked like a gorilla, or did it have longer fingers like a chimpanzee or orangutan? You may have short fingers A. afarensis hands that facilitate dexterity were simply a byproduct of the need for short toes to walk on both feet (because fingers and toes grow following a similar developmental path). Without knowing what the early hominin hand evolved into, we have a perennial chicken-and-egg problem: A. afarensis the evolution of the morphology of the hand in response to the need for skilled tool use, or was this morphology already present and merely co-opted for tool use? It might even be a bit of both.
The second major obstacle to testing the hypothesis that the last common ancestor of all apes was a skilled tool user is the inherent bias of the archaeological record. Evidence for tool behavior in deep time is limited to rocks, and only the rocks we have. recognize as a tool It is very likely that early hominins used unmodified stones as tools, and if we cannot see evidence of stone wear from use, we would not recognize them as such. Given the importance of plant-based tools in living ape and many human communities, it is likely that organic tools were essential to early hominin daily life. However, organic evidence is rarely preserved in the archaeological record. Promising new research led by my colleague Lydia Luncz of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany is helping to overcome this obstacle. He has shown that hammering with wooden tools produces changes in the internal structure of the wood that can be fossilized. This discovery opens an exciting new window into the identification of tool use much earlier in human evolutionary history.
Lucy’s influence on our understanding of the evolution of human dexterity and tool use stems largely from the fact that it was far older than any archaeological evidence of stone tool behavior at the time of its discovery, but her hand displayed some human-like characteristics. It sparked novel research into what separates the human hand from other primates and why it does so. Lucy encouraged scientists to suggest that improved hand dexterity evolved not only in the behavior of stone tools, but also in food processing or organic tool use, or even as a byproduct of bipedalism. Most importantly, Lucy, along with her research on apes and apes’ tool use, contributed greatly to the recognition that stone tool behaviors are not exclusive to humans.
