Health,  Life

The Price of Evolution: How Our Bodies Are Flawed by Our Past

  Back pain is a common trouble for modern people. When that feeling hits, we complain about being too busy at work, that the chairs aren’t comfortable enough, or that the gym wasn’t open lately. However, in the view of Endo Hideki, a professor at the University of Tokyo, this is first of all to blame for evolution-it stands to reason that the spine of quadrupeds should be parallel to the ground like a bridge, instead of standing up like humans to bear the weight of the entire upper body. Just like when eating a sandwich, the stuffing will always fall out. If the spine that was originally in a horizontal position is erected, the “stuffing” in the middle will slide outward under excessive pressure. This is the principle of lumbar disc herniation. .
  Evolution has allowed us to achieve the achievements of today’s civilization, but it has also brought us a lot of troubles. Hideki Endo studies comparative anatomy, dissecting animal remains to understand the evolutionary history of the body. In the book “Failed Evolution”, he combined fried chicken, saury and other common things as examples to describe how the human body has undergone changes. Compared with the time scale of evolution, the lifespan of an individual is insignificant, but the traces of evolution really exist in each of us.
Start with a piece of fried chicken

  If you buy fried chicken with the breast attached, look at the bones. There is a small bone like a toothpick in it, which is the chicken shoulder blade. In contrast, the human shoulder blade is broad, triangular and well developed. You can put your hands around your upper body and touch your back. The part you touch with your palms is your shoulder blades. Why is there such a difference?
  Next to the shoulder blade of the chicken, there is a thicker bone called the black coracoid. In anatomy, the scapula, coracoid and surrounding bones belong to the forelimb belt (called the upper limb belt for humans), which plays the role of connecting the forelimbs and the trunk. These bones have a very long history and have undergone different evolutions in different species. As birds continue to improve their flight capabilities, the black coracoid bone becomes more developed, and the scapula “retreats to the second line”; while in humans, the bones homologous to the black coracoid bone have long since disappeared, and the scapula has taken on a heavy responsibility, allowing us to Move your arms flexibly.
  Such cases show that in evolution, there is not only survival of the fittest and life and death. Different animals may use different methods to achieve similar functions to help the population survive. Endo Hideki wrote in the book: “It is common in the history of evolution to embark on different paths of destiny at a certain point in time, and finally achieve success in their own ways.”
Transform jaws into ears

  In the view of Endo Hideki, the case of the evolution of the forelimb belt can be called “design iteration based on old drawings”: evolution will not create new things out of thin air, each creature is just forced to take over what was left by the previous generation Old drawings, painted and modified on this basis.
  After many iterations, an organ may develop a completely different function from its initial stage. Ting Xiaogu is such a wonderful case. “In other words, the auditory ossicles have changed three functions in the past 500 million years. It was originally a respiratory organ, changed into a chewing organ in the jawed fish stage, and developed into a sensory organ in the mammalian stage.
  ” It was originally part of the “hinge” of the temporomandibular joint, the joint that controls the opening and closing of the mouth. Perhaps because this part is close to the depth of the ear, early mammals about 200 million years ago sent them into the ear to play the role of “sound amplifier”, and at the same time “reformed” a new set of temporomandibular joints with other bones , to ensure that the animals can eat normally.
  If we go back 200 million years, the history of auditory ossicles can even be traced back to the respiratory organs, specifically the arc-shaped cartilage connected to the gills of dark red fish, called gill arches. As for the origin of the gills and jaws, that is another story. Early vertebrates lacked jaws, and the birth of jawed fishes was an important step in evolutionary history, the details of which are still much debated. Interested readers can read the detailed narrative in the book and wait for more explanations given by scientific research.
The price of evolution

  From an anatomical point of view, the biggest difference between humans and other animals is the posture of walking upright. In order to adapt to walking upright, our body has undergone many changes. We have a well-developed tarsal bone (the bone around the heel) to complete the burden of carrying the weight of the whole body on one leg during walking; the pelvis is also developed to be larger than other animals to better support the internal organs. Adapting to upright walking allowed us to develop language and the ability to use tools, making civilization possible.
  However, the human body is far from perfect. The defects of evolution combined with the influence of modern living habits have brought us a series of troubles that other animals do not have at all, such as the lumbar disc herniation mentioned above, such as neck and shoulder pain, and cold hands and feet.
  Is there a chance for humanity to correct these flaws? Could we witness the next evolution of humanity?
  Unfortunately, Hideki Endo believes that the answer is no, and our proud brain “is the root of human failure.” There are creatures on the earth that have lived for tens of millions or even hundreds of millions of years. Only we humans have caused tremendous changes in the environment in just 5 million years, which has threatened our own survival. In his view: “Our human history will come to an end before the next design iteration occurs.” But he also pointed out with consistent humor that we can realize that we are failures, isn’t it also worthy of admiration?

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