Humans are the most successful primates on the planet, but our bodies won't get the Grand Prix for good design.
This is a summary of a session at the American Association for the Advancement of Science's annual meeting, where anthropologists, using hypotheses and fossil analysis, talked about adaptations that altered a body that was originally adapted to life in trees.
“Our anatomy wasn’t built from scratch,” said Jeremy Desilva of Boston University, USA. "Evolution works with duct tape and paper clips."
Mr. Desilva held up a cast of a human foot with 26 bones in front of the crowd and declared, "You wouldn't do this with 26 moving parts." There are so many bones in human feet because our ape-like ancestors needed flexible limbs that allowed them to cling to branches. When they climbed down from the trees and straightened their backs (and this happened about 5 million years ago), the foot gradually became more stable: the grasping thumb was no longer opposite to the rest, the arch appeared at the foot, acting as a shock absorber.
Figuratively speaking, nature has wrapped a lot of duct tape around our feet to make it stiffer, but we still have all these bones and they still have the ability to bend back and forth.
The result is flat feet, ankle sprain, plantar fasciitis, achillotendinitis, a split shin, ankle fracture. This is not at all a consequence of the fashion for stilettos: fossil specimens show healed ankle fractures, which are about 3 million years old.
According to Mr. Desilva, an ostrich foot and ankle design would suit us. In an ostrich, the ankle and shin bones are fused together, and only two fingers help to run. Why is it wrong with us? It's very simple! The evolution of ostriches dates back 230 million years, and our ancestor climbed on the hind limbs only 5 million years ago.
Then anatomist and paleoanthropologist Bruce Latimer from Case Western Reserve University (USA) entered the stage, waving a twisted human spine, which was painful to look at. “If you want an example of duct tape and paper clips, here it is,” announced a specialist who himself had survived back surgery.
Promotional video:
When the man straightened up, he had a stiff spine that developed for climbing trees. Now - imagine that you took 26 cups and saucers (vertebrae and intervertebral discs) and arranged them horizontally, and then suddenly lifted them up 90 degrees. A heavy head was also placed on top. In order not to interfere with the birth canal and so that the torso can maintain balance, the spine curved inward (this phenomenon is called lordosis).
That is why our ridge resembles the letter "S" (the curvature of the upper section outward is called kyphosis). But this did not solve the problems with the pressure on the spine. And if you are actively playing football, doing gymnastics, swimming butterfly style, the probability of trouble is high. In the United States alone, 700 thousand vertebral fractures are recorded annually, and back problems are in sixth place in the list of the most common ailments of mankind. “If you take action, you can easily live to be forty or fifty,” said Mr. Latimer. "After that, I can't vouch for you."
Paleoanthropologist Karen Rosenberg from the University of Delaware (USA) decided to move away from the painful topic. Walking upright and increasing the volume of the brain led to another problem. The birth canal was too narrow. Until very recently, childbirth was the leading cause of death among women of childbearing age. Compare: the size of a human newborn is close to 6.1% of the size of the mother, while in chimpanzees and gorillas this figure is only 3.3 and 2.7%, respectively.
The solution to this problem, apparently, was the emergence of a kind of obstetrics, that is, it was dangerous for the female to give birth without assistance. The fact that today about 30% of births in the United States are performed by caesarean section speaks for itself.
What is the conclusion from this? Evolution does not create anything, said anthropologist Matt Cartmill from Boston University (USA) during the discussion. Genes and traits are randomly changed to survive in a new environment. The concept of "perfection" for nature simply does not exist. Only "function".