- #Strength of a chimpanzee compared to a human software#
- #Strength of a chimpanzee compared to a human crack#
2005 Richmond and Jungers 2008 Lovejoy et al. We conclude that the evolution of endurance at the cost of strength and power likely also involved the evolution of mechanisms to resist fatigue.Īlthough humans differ from other mammals in numerous respects, the fossil record supports Darwin’s 1871 speculation that a chief initial difference that set the human lineage on a separate evolutionary path from the apes was habitual bipedalism (Zollikofer et al. We review the trade-offs between strength, power, and stamina in apes and Homo and discuss three biological systems that we hypothesize humans evolved adaptations for fatigue resistance: neurological, metabolic and thermoregulatory. Our hypothesis is that since fatigue is an important factor that limits the ability to perform endurance-based activities, fatigue resistance was likely an important target for selection during human evolution for improved endurance capabilities. In this review we explore the hypothesis that to be effective long-distance walkers and especially runners, there would also have been a strong selective benefit among Homo to resist fatigue. By 4 million years ago, hominins had evolved the ability to walk long distances but extreme selection for endurance capabilities likely occurred later in the genus Homo to help them forage, power scavenge and persistence hunt in hot, arid conditions. The two most widely supported selective forces for this adaptation are increased efficiency of locomotion and improved ability to feed in upright contexts.
#Strength of a chimpanzee compared to a human crack#
"But we have not strongly compromised our ability to either crack a hard item or bite off a good chunk of flesh.Humans differ from African great apes in numerous respects, but the chief initial difference setting hominins on their unique evolutionary trajectory was habitual bipedalism. "So we certainly have lost some of the capacity that great apes have," he said. While humans are capable of a powerful maximum bite force, which is useful for cracking nuts or biting into meat, they are less well adapted for hours of chewing tough leaves and bamboo tubers, said Wroe. And where the muscles attach and the way they are arranged," he said. It's about where the fulcrum is - or the jaw joint in this instance. Wroe said it basically comes down to leverage.
"Pound for pound we're actually biting harder than a gorilla or a chimpanzee," said Wroe, adding there's no big difference between the bite force of a human and the nutcracker man, once body size is allowed for. The researchers say the design of the human jaw makes it 40 percent to 50 percent more efficient than for all great apes. "For any given bite force you want, we can achieve it with much less muscle." "When you actually look at the mechanics of it, the human jaw is highly efficient," said Wroe. The researchers simulated a scenario in which the animal was biting a hypothetical hard object with its back teeth, and visualized how stress was distributed. They used a method called 3D finite element analysis to study digital models of skulls that had been CAT-scanned.
#Strength of a chimpanzee compared to a human software#
Wroe and colleagues used sophisticated engineering software to compare the maximum bite force of modern humans with that of four living apes (chimpanzee, gorilla, orangutan and gibbon) and two fossil hominids (Australopithecus africanus and Paranthropus boisei - also known as "nut-cracker man"). He said the very thick tooth enamel coating human teeth is generally associated with processing hard foods in primates. Some scientists argue a weaker bite evolved in response to humans eating softer foods, processing them with tools and cooking.īut, said Wroe, there has been no direct data to support these conclusions. He said this has been driven by the fact that humans have relatively weak jaw muscles and lightweight skulls, compared to our fossil ancestors and living great apes. "The traditional view is that modern humans have lost the ability to generate a powerful bite," said Wroe.
Stephen Wroe from the University of New South Wales in Sydney and colleagues reported their comparison of human and other skulls recently in the Proceedings of the Royal Society B. Humans have a much more powerful bite than previously thought, thanks to the mechanics of their skull, say Australian researchers.
0 kommentar(er)
