![]() ![]() Evidence suggests that metacarpals have elongated in apes while they have shortened in humans since our last common ancestor. Longer fingers are associated with grasping tree branches to hang from. Humans use their hands with a combined precision and strength grip that allows us greater dexterity with our hands.Īrdi’s fossils are useful for determining when hands diverged between humans and other apes. Chimpanzees use their fingers to grip sticks while humans use their thumbs to allow for greater control and precision. They have short thumbs and long phalanges compared to our more modest phalanges and large, strong thumbs. Our hand bones are different than those of chimps in very significant ways. Next, Roberts discusses the ability of human and ape wrists to be in both supinated and pronated positions allowing us to use our hands for even more things. Skeletal differences between human and chimpanzee hands show that our hands serve different functions despite their seeming similarity (Roberts 324). ![]() ![]() There is conclusive evidence that throwing was used for hunting by 300,000 years ago. There is little fossil evidence of throwing before the invention of tools specifically designed as projectile weapons such as throwing spears. This seems to have been very important because much of our anatomy seems well suited for throwing. Some suggest that the change in shoulders may be because of advantages for throwing. Perhaps they conferred an advantage for long distance running. Roberts discusses possible reasons that our shoulders have rotated downwards. Other apes have more upward facing shoulders because of their use for climbing. They have the ability to pronate which allows rotation around the arm-hand axis. Shoulders are a very mobile and as a result of this mobility, they dislocate more easily than more stable joints. We have free-floating scapulae and very mobile arms. Our shoulder anatomy is owed in part to our climbing ancestors. Human arms and hands are much more mobile than those of most other mammals. She also talks about the things we share with other apes as well as what sets us apart and why these differences may have arisen. The study, entitled Metacarpal trabecular bone varies with distinct hand-positions used in hominid locomotion (Christopher Dunmore, Dr Ameline Bardo, Professor Tracy Kivell and Dr Matthew Skinner, Skeletal Biology Research Centre, SAC, University of Kent) was published in the Journal of Anatomy.In this chapter, Roberts addresses the unique physiology of the human shoulder and hands and how they reflect our evolutionary past. This matters because when we find ancient human hand fossils that preserve their internal structure, we can work out if they were probably swinging from trees during their lifetime or if they were walking on the ground more like humans today." Mr Dunmore said: "For the first time we see interesting internal bone patterns differentiating subtle differences between chimpanzee and gorilla knuckle-walking, as well as arboreal grasping in orang-utans. The information will now enable scientists studying fossils to better understand whether ancient humans were swinging from trees or walking on the ground. The researchers found the knuckle joints of orang-utans were consistent with flexing the knuckles while grasping branches, while the joints of chimpanzees, bonobos and gorillas were consistent with knuckle-walking - the most frequent ways in which these animals move around in their respective environments. The study compared the internal bone structure of the knuckle joints in chimpanzee, bonobo, orangutan and gorilla hands, to assess whether this bone structure records how these apes moved when knuckle-walking on the ground or hanging from trees. When it is preserved in fossils, researchers can learn more about how ancient apes as well as humans moved and interacted with their environment. Trabecular bone is a honeycomb structure that is found within most bones and changes depending on what that bone is used for during a lifetime. Using samples from the Powell-Cotton Museum in Birchington-on-Sea (UK), as well as samples from Germany, Belgium and the USA, a team led by School of Anthropology and Conservation (SAC) PhD student Christopher Dunmore examined the internal bone structure, called trabeculae or cancellous bone, of great apes. ![]()
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