Something I read today that reminded me of the importance of seeing the big picture, and how seeming “improvements” in one area can have drastic implications in the overall picture.
Joseph Burdo, Assistant Professor of Biology at Boston College, wrote a comment entitled “Design Flaws” in response to a Wired magazine article on “10 Worst Evolutionary Designs.” Professor Burdo wrote:
“[Y]ou forgot about one of the best arguments against the "theory" of intelligent design: the shared opening to the esophagus and trachea in humans (and many other mammals). Hundreds of choking deaths occur in the US every year due to food obstructions in the trachea. Doesn't seem too intelligent to purposefully design such a hazard.”
If you’ve ever had food or water go down the wrong way then you’ve experienced this “bad design” first hand. This argument was also listed in a 2001 Scientific American article called “If Humans were Built to Last” by S. Jay Olshansky, Bruce Carnes, and Robert Butler. The authors suggested that a better design would feature independent tubes for breathing and eating.
But though it seems so obvious that a dual tube system would eliminate the possibility of choking, and seems like a much better design, consider some of the implications of this change. Have you ever had a bad cold, so bad that your nose became completely plugged up and the only way you could breathe was through your mouth? With our current shared opening between mouth, nose, and trachea, nasal congestion is an uncomfortable but minor nuisance. But if the nose was the only means of getting air to the lungs, then nasal congestion would potentially be a fatal condition! Instead of a few hundred people dying of choking each year, you would be looking at possibly millions of people dying from asphyxiation due to the common cold or allergy symptoms.
There would also be the problem of getting rid of liquid that accidentally enters the lungs. It would have to be pushed all the way up to the nose and expelled there (make sure you carry lots of tissue with you!). Under the current system, it need only go to the top of the trachea and the down the esophagus to the stomach. The two tube design would also restrict the amount of physical activity that humans could do. When we run, we take in air through our mouths, since the larger opening allows for a more rapid respiration rate. The only way to allow for a large respiration rate with one tube to the nose would be to greatly increase the size and openings in our nose. Not only would this look ugly, but the larger openings would present problems. Things could enter into such large openings and have direct access to your lungs (How would you like to inhale a fly into your lungs?). Larger nasal passages would also reduce the temperature of the air, since it could not be heated as effectively (important for cold climates). Another major problem would be speech and language. We need to use our mouths and tongue in order to produce speech. Air running over vocal cords, in the absence of a tongue, lips and teeth, would only be able to produce a very limited number of sounds (it might not affect Rambo, but the rest of us would have a difficult time communicating). Try it some time (hold your mouth open and don't move your tongue as you attempt to communicate). Of course the evolutionist might propose additional structures in the nose (like a tongue, lips and teeth-like structures).
So, here is what the evolutionists are proposing for a superior breathing apparatus. Our trachea would continue up to our nose, requiring our necks to be at least 1 inch wider. We would have huge noses with nose lips and a tongue protruding out. Of course, our faces would have to be much longer to accommodate the additional structures. Now, we would really be ugly! On second thought, it might be interesting trying to kiss with two sets of lips - nah, constantly expelling liquid out our nose would make it kind of gross. Aren't you glad you weren't designed by an evolutionist!
Even in a well designed and engineered system, it may seem as if you can improve one specific aspect of the system by changing a certain part, but what you quickly discover is that even minor changes lead to consequences that actually degrade the functioning of the system as a whole. In considering “bad designs” in nature, it’s critical to remember that living organisms do not function as a set of independent parts, but as cohesive and finely tuned wholes. Most arguments of “bad design” in nature fail to appreciate this intertwining cohesiveness.
Human throat image obtained from the Mayo Foundation for Medical Education and Research (https://www.bcbsri.com/BCBSRIWeb/images/mayo_popup/Yourthroat.jsp)