![]() ![]() As a result, chimps and orangutans do not have opposable thumbs as we do. ![]() ![]() Since the thumb is not as long, it just meets up with the palm, while the chimp's other four fingers extend upward. "Human hands are marked by a relatively long thumb when compared to the length of their four other fingers - a trait that is often cited as one of the reasons for the success of our species because it facilitates a 'pad-to-pad precision grip,'" says Hiatt.Ĭonversely, chimp hands are much longer and narrower. The researchers, led by Sergio Almécija, a scientist in the university's Center for the Advanced Study of Human Paleobiology, analysed the hands of humans, chimps and orangutans, as well as the remains of hands for early apes like Proconsul heseloni and the hands of human ancestors, such as Ardipithecus ramidus and Australopithecus sediba.Īlmécija and colleagues, Jeroen Smaers and William Jungers from Stony Brook University, discovered that human hands today are not that different from those of the early human ancestors. "The findings suggest that the structure of the modern human hand is largely primitive in nature, rather than, as some believe, the result of more recent changes necessary for stone tool-making," says Kurtis Hiatt, a spokesperson for The George Washington University. The study, published in the the journal Nature Communications, found that human hand proportions have changed little from those of the last common ancestor of chimps and humans, while the hands of chimps and orangutans have evolved quite a bit. Hand evolution The development of an opposable thumb that enables humans to grip and manipulate objects is widely believed to give us an evolutionary edge.īut new research finds that human hands are more primitive than those of our closest primate ancestors chimpanzees. It was only much later that our larger brains and more complex technology set us apart as Homo sapiens.Human hands are marked by a relatively long thumb when compared to the length of their four other fingers (Source: stockdevil/iStockphoto) increasingly complex forms of technologyįossil evidence shows that our ancestors became bipeds first, followed by changes to the teeth and jaws. bipedalism (walking upright on two legs) 2.These can be summarised as trends involving the development of: Our own species Homo sapiens is the result of four major evolutionary changes. The ancestral line that led to modern chimpanzees also changed, possibly with changes that were as dramatic as our own. Millions of years of evolutionary change and natural selection meant that later hominin species were less apelike in appearance and behaviour than their early ancestors. It is highly likely that A.ramidus preserves some of the characteristics of the last common ancestor, suggesting that some of its features (particularly in the limbs and hands) were more like those in living monkeys and early apes like Proconsul. The fact that A.ramidus has a number of physical features that differ significantly from chimpanzees (particularly those that show it was not a knuckle-walker) is crucial to our understanding of hominin and ape evolution. This species dates to a critical time in hominin evolution as it is nearing the time when scientists believe hominins diverged from the ape branch of the family tree. Recent studies on the skeleton of the 4.4-million-year-old Ardipithecus ramidus have changed all this. However, this lacked supportive fossil evidence as there are almost no fossils of early chimps or gorillas and very few of early hominins. This view was based on the beliefs that our ancestors probably passed through a proto-ape stage and that African apes are less specialised than humans so have changed less since diverging from this ancestor. Until recently it was widely believed that it looked much like a chimpanzee, with features such as a short back, arms and hands adapted for grasping and swinging in branches, and wrists and forelimbs that enabled knuckle-walking. What this common ancestor looked like is not known. Most scientists believe that the ‘human’ family tree (known as the sub-group hominin) split from the chimpanzees and other apes about five to seven million years ago. Evidence from fossils, proteins and genetic studies indicates that humans and chimpanzees had a common ancestor millions of years ago. ![]()
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