TUESDAY, 26 FEBRUARY 2013A team at Case Western Reserve University, led by Meghan Cotter, PhD, looked at vertebrae across orang-utans, chimps, gorillas and humans. Comparing the relative vertebral size, shape and internal structure, the team found that apes have shorter and wider vertebrae with a thick shell of bone round a porous middle. In contrast, humans have larger vertebrae for their body size and the shell of bone surrounding the middle is much thinner.
The researchers suggest that this difference in vertebrae is a result of the different evolutionary paths of apes and humans. Whilst the apes’ vertebrae provide the stability needed when climbing trees or walking on all fours, the humans’ larger vertebrae appear to have adapted to absorb the impact created when our two feet hit the ground. However, the thinner shell of bone means that less bone loss can occur in humans before the risks of fractures increases, a pattern which the team observed in medieval and modern humans. This finding contradicts previous research which has suggested that our modern day diet and less active lifestyle are the cause of bone loss and damage.
"In evolution we have great adaptation, but there is sometimes a trade-off," says Cotter, "The structure is great for walking around, but not good when you have osteoporosis.” This team is not alone in pointing to our evolutionary past as a source of current health woes; a recent panel at the American Association for the Advancement of Science's annual meeting presented evidence which suggests that a variety of ailments from bunions to slipped discs are a result of our ancestors learning to stand on their own two feet.
Written by Arielle Bennett.