Shifting to Agriculture Made Human Bones Weak
Agriculture may have helped Homo sapiens establish societies but it gave weaker bones in return.
According to IB Times, researchers at University of Cambridge claim the transition from hunt gathering to agriculture reduced the amount of load bearing by bones, leaving modern humans susceptible to conditions like osteoporosis in middle and old ages. The study showed modern humans had bone densities substantially lower than other primate and non-primate hunter gathers like orangutans though anatomically there is no difference between modern man and the rest.
"Contemporary humans live in a cultural and technological milieu incompatible with our evolutionary adaptations. There's seven million years of hominid evolution geared towards action and physical activity for survival, but it's only in the last say 50 to 100 years that we've been so sedentary - dangerously so. Sitting in a car or in front of a desk is not what we have evolved to do," said study's co-author Dr Colin Shaw, in a news release.
Researchers arrived at their conclusions by analyzing trabecular bone (soft bone tissue inside the bone) densities of orangutans, chimpanzees and baboons besides that of Neanderthals, Paranthropus robustus, Australopithecus africanus and other Australopithecines. They found that bone densities of modern humans were 50 to 75 percent lesser than the rest, The Washintong Post reported. The study found that the changes in bone density happened around 12,000 years, when humans took to farming.
"Trabecular bone has much greater plasticity than other bone, changing shape and direction depending on the loads imposed on it; it can change structure from being pin or rod-like to much thicker, almost plate-like. In the hunter-gatherer bones, everything was thickened," Shaw said.
Loading on the bone causes minor damage and the following repair helps make it dense and strong. Researchers were also able to rule out that diet may have caused bones of modern humans to thin out.