Craig Engert
Author: Charlie Choi
Published:December 29, 2014
Link: http://news.discovery.com/human/evolution/modern-human-bone-density-drop-tied-to-lifestyle-shift-141229.htm
Summary: Bone is one of the strongest materials found in nature. Bone in the same quantities is actually stronger than steel. Human bone however is getting weaker and weaker. Scientists believe the change in density of the human bone may provide insight to bone conditions such as osteoporosis. Despite a vast amount of research on the human skeleton, this is the first study, thanks to the help of imaging technology, to prove that modern humans have substantial lower bone density then their ancestors. Currently scientist have found that modern human bone is about one half as dense as modern primates and our early ancestors. The significance of human bone density decreasing is that the human bone density shift was not gradual as one might expcet, rather bone density has decreased rapidly since the Holocene Epoch which began about 12,000 years ago. The change in bone density is more notable in lower joints of the knee, hip, and ankle rather than the shoulder, elbow, and hand. Denoting to the idea that most likely the lack of bone density is due to lack in activity due to technology. However, the bone density change may also had been impacted by a deficiencies in dietary calcium.
Connection: An adaptation is a change in an organism to be better suited for the environment. Thus, the article relates to Unit 7 The Evolution of Life. In this unit we have learned about adaptations. Surprisingly enough lower bone density is an adaptation in the human species. Unlike our primitive ancestors modern humans now have access to technology. With an increase in technology humans no longer need the bone density which was required by their ancestors. With technology humans can and could use less energy to do an activity. With farming and other technology ancient and current less amount of energy must be exerted in humans main task of finding food. Thus, high human bone density is not essential for humans as it had been for their ancestors so humans as a species adapted to their environment filled with technology and loss bone density as it is not essential to the human species to survive, and the resources can be used in another way.
Have similar studies been done on other species to determine if this change in bone density is occurring in other species?
ReplyDeleteI could unfortunately not find any other studies on bone density of other animals. Taking into account that this is the first study to prove it in humans i doubt there are any out there now. However, I would not be surprised if there were other studies in the future to see. Assuming that the reason for the change in bone density is a lack of exercise I would guess domesticated animals would most likely also have a change in bone density.
DeleteHow recently has bone density dropped? Would there be another reason for this if it has been dropping since before much modern technology?
ReplyDeleteBone density started to drop around 12,000 years ago which was when humans as a species became more settled and less nomadic and we were farming and had primitive technology. Thus, they believe that the most likely explanation for this phenomenon is a decrease in exercise.
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