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Límulus

Evolutionary
pains

Text by Alejandra Ortiz Medrano

Photographs by Toumani Camara 

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Just as the traces of time on the mountains that slowly erode, day in and day out, shaping the landscape, evolution shapes all living creatures: their structure, behavior and genes. For us humans, our bodies are landscapes filled with potholes; pains and ailments constitute the marks that remind us what evolution has done to us, what we are today: a walking imperfection.

Stressed backs

We proudly boast being the only primate that is completely bipedal. The upright posture allowed the ancestors of the human race to free their upper limbs – the arms – from movement. Millions of years later, this gave way to much idleness, but when this evolutionary novelty appeared, it offered the great advantage of using these limbs to create tools and transport food along great distances.

The switch from being parallel to being perpendicular to the ground, besides its advantages, brings a number of unique problems to humans: scoliosis, herniated discs, spontaneous spine fractures, among other back pains. These have even been identified in fossils of ancestral species like Lucy, estimated to be 3 million years old.

The reason we suffer from these problems is due to us walking straight because of the curvature of the spine necessary for the small bones of the vertebrae to balance the torso and hold our head, which weighs approximately five kilos. Humans’ curved spine is unique in the animal world, as well as the painful consequences it entails. Due to the weight it holds, its “S” shape and the constant balancing of the arms in the opposite direction of the legs, the pressure the vertebrae bears is easily stressed, causing the aforementioned conditions and, more frequently, back pains.

These pains aren’t the only ones our big head has caused. Thousands of people go on daily visits to the dentist due to another of our painful evolutionary marks.

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Wisdom teeth

Although it does not have anything to do with wisdom, or judgment, or intelligence of the subject at hand, the third molars and their complications have to do with the evolution of a big head in humans that, one could argue, knocked some judgment into our species, although it is highly questioned.

The encephalization, as the upright posture, is another of the peculiar characteristics of the human species. Our head is proportionally larger than any other mammal’s. Compared to that of a chimpanzee’s (our closest evolutionary species), a human’s head is three times larger. The cranial capacity and what it contains – the brain -, allowed our ancestors to develop sophisticated skills that helped them survive and colonize practically the entire world.

But the head’s evolution had a price. In all primates, jaw muscles are subject to cranial crests: the larger the gripping surface, the stronger the jaw. The human skull lost these crests almost in its entirety, which liberated the pressure that existed to increase the volume where the brain is located, at the same time, reducing the size of the jaw. Currently, this reduction results in dentist visits because of the lack of space the third molars have to come out.

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Collapsed feet

Life on the trees required agile and prehensile limbs, like the hands and feet of apes. Once it left life in the trees, the foot of the human lineage was remodeled in such a way that it helped the balance and support required to walk vertically. But as with everything, evolution worked with the existing material.

The human foot is made up of 26 moving bones, many more than those a good engineer would consider necessary for a rigid structure whose main function is support. This inheritance of our arboreal past is not only obsolete but also bothersome and painful. Despite the bones of the foot loosing almost their entire capacity of movement, they’re still there and sufficiently mobile to collapse or cause several pains innate to humans: twisted and broken ankles, swelling of the soles of the feet and tendinitis.

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Perfect bodies?

Had it known, evolution should’ve created feet with fewer bones, thicker spines and eliminated the wisdom teeth completely. It could’ve also made us less susceptible to sickness, provided us with wings and night vision. The problem is that evolution works with the existing material, mainly with the traits we drag from our ancestors, however unpleasant, uncomfortable and useless they might seem. The only certainty we may have regarding the future of humankind is that we will remain as far from perfection as we are now.

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