Evolution fun facts: A nerve stupidly long.

I often stop considering the beauty and the efficiency of our body, like the ones of many other living organisms. I do it so often, that I almost convinced myself that we are perfect. For me that’s not a problem, we could be perfect in every sense, and the only this I will perceive will be the amazing handiwork of natural selection and evolution. Many people, however, think that this perfection can be part of a bigger project, like the one of a God. Some call it “Intelligent Design”. Although it is probably a really intelligent design I don’t see why God should have made it. Leaving this discussion behind,we need to specify something: we are not perfect. Not even close. And for many aspects we are not even intelligent designed.

Let’s consider some aspects that would ashame God if He would’ve really made it. Instead we can simply explain some ankward stuff we find around the living world thanks to evolution.

Let’s talk about the title: A nerve stupidly long. A real example of stupid design.

Through evolution and embrional development many things change. One of them is the evolution from the Gills to our ears and lrynx. During the development of fishes, a nerve (neuronal cells) is formed that connects the brain to the 4th gillian arch, one of the arch which will form the Gills (the organ which through fishes absorb oxygen, breathing). Ok, if a fish need this nerve we are cool. What happened to us? We still have this nerve, but we don’t have gills anymore. Instead the nerve goes from the brain to our Larynx. That’s cool too.

There’s one single problem. From the 3rd gillian arch the Aorta forms. Where is the problem? That the Larynx nerve has to pass behind the Aorta before going up to the Larynx because mechanical constraints derived from the initail “project”.

A sketch of the situation illustrated. We can see the evolution of the structure of the gillian arches into the 3 (4th, 5th and 6th) arch arteries. On the left the situation make sense, but on the right we can see that the nerve, called the left reccurent laryngeal nerve, is obliged to pass over the ductus arteriosus, which would be the Aorta in mammals.
A sketch of the situation illustrated. We can see the evolution of the structure of the gillian arches into the 3 (4th, 5th and 6th) arch arteries. On the left the situation make sense, but on the right we can see that the nerve, called the left reccurent laryngeal nerve, is obliged to pass over the ductus arteriosus, which would be the Aorta in mammals.

Imagine the hearth and all the tubes that get out it. The left Reccurent laryngeal nerve must go down from the brain, pass over the Aorta and go back up to the larynx. That’s is obviously an example of stupid design, perfectly explainable in the light of evolution. For the body is actually a waste of resource, the nerve could do a far shorter journey from the brain to the larynx, howevere, this was the project, and it never changed.

Someone could think, well that’s actually some centimeters longer than the optimal length. Although this should be a problem anyway, because nature tends to optimize everything, we actually have a quite short neck. Can you think of an animal with a longer neck? Yes. The Giraffe has the same problem! Which means, that giraffes have a left reccurent laryngeal nerve almost 4 meters long !! That’s a waste of resources!

Evolution can be as smart as stupid, sometimes it can be even hilarious. Let me tell you a story..

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