I learned this today. Why would we evolve with a throat and windpipe that are so close together we can choke?
In 2019, 5228 people choked to death in the United States. As a cause of death, it was the fourth highest. Chocking happens when an object, typically food, blocks the throat or windpipe cutting off air to the lungs. It is most common among children under two-years-old and adults over 75, but anyone can choke at any age. The most common foods that cause choking are soft foods that can change their shape to completely block the windpipe, such as bananas or marshmallows.
When you swallow food or drink, a piece of skin called the epiglottis, protects your windpipe. It is an elastic piece of cartilage that sits at the top of the larynx. It is open and pointed upwards normally, to allow air down your windpipe. When you swallow food, the action of swallowing pulls the epiglottis down so it blocks the windpipe and allows food to slide down the esophagus. If you eat quickly, food can sometimes slide down your throat before the epiglottis has time to close, entering your windpipe.
So, why would we evolve to have the esophagus and the windpipe next to each other? It seems like an accident waiting to happen.
Well, the first problem with this question is that we don’t evolve for intelligent reasons. We evolve because a mutation happens to have an advantage that allows it to be passed on to subsequent generations. So, the better question would be, “what advantages does having an esophagus next to the windpipe bring us that outweighs the risk of choking?”
Well, the simple answer is “being able to talk.”
At the top of the windpipe, we have the larynx. One of the functions of the larynx is to produce sound. This is what lets us talk.
When humans are born, the tongue is flat in the mouth and the larynx is anchored to the root of the tongue. When babies drink milk, they raise their larynx to make a sealed passage that the milk flows around. This means they can drink and breathe at the same time with very little risk. Most animals are exactly the same as this. Dogs and cats can eat, drink, and breathe at the same time.
As children grow up, the shape of the head, neck, and mouth change. The larynx drops as the neck gets longer. The mouth shape changes, and the root of the tongue moves back into an area called the pharynx (at the base of the head, just above the epiglottis).
This changed mouth shape and tongue configuration allows us to do something that other animals cannot do. It allows us to move our tongue in extremely complex ways and to produce vowel sounds, especially a, i, and u, which are produced at the back of the tongue. These sounds and our tongue’s ability to make them have allowed the development of complex language.
The ability of complex language was obviously a distinct evolutionary advantage. It aids hunting, you can communicate ideas, knowledge can be passed from generation to generation through storytelling, and so on. There are obviously a lot of distinct advantages, and, in anyone’s book, these advantages would outweigh the slight risk of choking to death.
Animals don’t choke because their larynxes are still attached to the roots of their tongues, but that means they are unable to make complex shapes with their tongues and will never be able to talk in the way that we can.
So, why would we evolve with a throat and windpipe so close together that we can choke? Well, evolution doesn’t happen intelligently, and it happened because this configuration gave humans a distinct advantage. That advantage was language. The position of our tongue is different to all animals, which means we can make sounds they cannot. Our throat and windpipe are so close together because being able to communicate outweighs the risk of choking. And this is what I learned today.
Photo by Sergey Makashin from Pexels: https://www.pexels.com/photo/happy-little-girl-eating-tasty-croissant-5368735/
Source
https://www.npr.org/templates/story/story.php?storyId=129083762
https://www.cracked.com/article_19890_5-ways-evolution-has-screwed-us-over.html
https://evolutionnews.org/2018/07/oral-cavitys-supposedly-lousy-design-is-a-key-to-human-speech/
https://www.theatlantic.com/science/archive/2019/12/when-did-ancient-humans-start-speak/603484/