The Evolutionary Flaws of the Human Body: A Physiological Overview
Evolution has shaped the human body into an intricate and complex organism, but as with any process of improvement through trial and error, there have been some inevitable design flaws. This article explores three significant examples of shortcomings in our physiology, specifically the human eye, spine design, and knee design.
The Flawed Design of the Human Eye
From a physiotherapist's perspective, one of the most glaring flaws in human anatomy is the design of the eye. Unlike many primates and some other animals, the human eye is "inside out," meaning the blood vessels lie in front of the light-detecting cones and rods in the retina, which the brain must process to exclude from our visual experience. This is by no means a perfect design. Further exacerbating the issue, the eye contains a blind spot where the blood vessels and nerves exit the back of the eye. The brain attempts to fill in this gap with its predictions of likely sensory stimuli, but this can lead to visual distortions and limitations.
The process of evolution has hardly done the eye any favors. In the early stages, the anatomy of the eye was already somewhat flawed, and the subsequent evolutionary changes only built upon these original imperfections. Octopuses, for example, have correctly oriented eyes in this regard, but they face their own set of design challenges and workarounds that come with being an octopus. Nonetheless, the human eye's compromised design is a significant physical limitation that affects our ability to perceive the world accurately.
The Awful Spine Design
The spine, another critical component of the human body, is also subject to various design flaws. One of the main issues lies in the segment lumbar vertebrae 4 and 5. Since humans have evolved to stand upright, these joints are exposed to significant strain, which can lead to calcification. Interestingly, the article suggests that there are no supporting muscles for the lower thoracic and lumbar spine. The transverse abdominus and multifidus muscles, which are crucial for core stabilization, are often treated as skeletal phasic muscles by many American therapists, leading to ineffective exercises and, consequently, poor spinal support. These muscles are in fact postural, and their strength can be significantly improved by holding contractions for extended periods, a technique that allows for better core engagement.
From the perspective of a physiotherapist, it is argued that postural muscle strength is essential for maintaining a healthy spine. Holding a contraction for 100 counts while still being able to breathe freely is key to effective muscle recruitment. This approach is more nuanced and results in better overall muscle engagement and support for the spine.
The Inadequate Knee Design
The knees, another often-overlooked area of the body, also suffer from design flaws that can lead to significant wear and tear over time. As humans are not designed to live into old age, the durability of the knee joint is a major flaw. The knees tend to last significantly less time than the rest of the body, leading to a high incidence of knee-related issues in later life. This is a testament to the fact that the design of our knees is not optimally suited for prolonged use.
Apart from the knee's overall durability, the human knee lacks the muscular strength and supportive structures seen in other mammals. Our ancestors, who were closer to primates, had more robust muscles for thrust, and great apes have the necessary strength to lift themselves off the ground. However, humans lack these muscles, and we have not evolved to have feathers for lift, similar to birds. These shortcomings also extend to our swimming capabilities, which are not as effective as those of other mammals. Our respiratory and cardiovascular systems, while complex, are limited in their functional abilities.
Physiologically speaking, the human body is a far cry from what could have been optimized for our current activities. The evolution process has not necessarily resulted in a flawless design but rather a complex interplay of adaptations that often leave us with less than ideal physical attributes for our lifestyle.
It is possible that the entire evolutionary process behind the human species as we know it is a significant natural unintended flaw. This notion raises intriguing questions about the true purpose and optimization of our anatomy.