Top 10 explanations behind certain body parts, now you know

You have most certainly already asked yourself, during a day of deep boredom, with a most intelligent voice: “uuuh why do we have eyebrows? » It took you aback for a few hours, or even the whole night that followed, literally preventing you from sleeping. Well I’m here today to answer this kind of question and explain to you what these weird parts do in our human body. But above all, a little reminder so as not to upset our friend Darwin – a reminder that will be useful for understanding the rest of the article: the parts of the body that we have are all the result of an evolution. If they are present, it is either because they were useful to our ancestors (and therefore perhaps doomed to disappear), or because they are still useful to us. If you want to know more about the subject, we have a top of the parts of the body that are still evolving, but in the meantime, here are the answers to the questions which prevent you from diving.

1. The little pink corner in our eye is the remnant of a third eyelid

Eyelids, a priori, we both have them: one at the top, and one at the bottom. They meet at more or less regular intervals to protect our eyes from dust and other projectiles while moistening them. It is convenient. But some animals, such as reptiles, birds, amphibians or some felines, have a third, horizontal eyelid. It has the advantage of not being completely opaque, which protects the eye while continuing to see a little. This is handy when hunting, for example. We humans don’t have it anymore, but we still have this pink corner in the eyelid, nicely called “semi-lunar fold”, which still has a use: it allows a greater rotation of our eye and favors its humidification. So even if scientists have no idea why we don’t have a third eyelid, we at least know why this semi-lunar fold shouldn’t disappear anytime soon in our descendants. So be reassured.

2. The coccyx is a remnant of the tail of our ancestors

As you know, the human being is a descendant of the great primates, and these primates had tails, very useful for walking in the trees. It turns out that this tail ended up losing its usefulness among our ancestors, and some were born with increasingly shorter tails (no, don’t giggle), then with more of a tail at all (no really, that’s it). is not funny). It was never a handicap since we no longer lived in the trees. Today, we therefore live without a tail, but our coccyx is still there, and it is a vestige of this tail of our ancestors. It still has a use, since it holds certain organs of our body in place and serves as an anchor point for our pelvic muscles. Muscles that are quite useful because they help us (among other things) to keep us from urinating on ourselves. To make a shortcut, we could thus say that without coccyx, we should wear diapers.

3. We get goosebumps because our ancestors were very hairy.

The great primates from which we descend, and even the first species of hominids, had a well-furnished coat, unlike us who only have a few more frankly very useful hairs. And our ancestors, like other mammals that still have coats, could make their hair stand up when they were cold (to better trap heat) or scared (which made them appear more imposing). The muscles that were used to erect the hair, we still have them. They are called “hair arrector muscles” and give us goosebumps when we are cold or scared, even if it no longer serves us any purpose.

4. Our wisdom teeth hurt because we no longer have room to accommodate them

What good are molars that hurt when they grow and that often have to be removed? Nothing, indeed. They were useful for our ancestors who had to chew food much harder to eat than our current food. They had a larger jaw than ours, so they didn’t hug their mother when their wisdom teeth grew, unlike us. If we no longer have room for these teeth, it is partly because we have larger brains than those of our ancestors. Brains that take up more space in our cranium and leave less for the jaw. So, would you rather have extra molars or enough IQ to run your coffee maker? For me the choice is quickly made.

5. The muscles of our ears are only pale copies of those of our ancestors

We all have muscles that allow us to slightly move our ears, which today is particularly useless, except when you want to make yourself interesting in the evening by showing that you know how to wag your hatches. This performance would make our ancestors laugh gently, who could boast (even if they remained humble, in my opinion) of really being able to direct their ears in the direction of a sound, like a lot of mammals. It is an essential ability for survival when hunting or being hunted. Two situations which, you will grant me, do not happen to us too much these days.

6. The appendix isn’t completely useless (contrary to popular belief)

Until fairly recently, it was thought that the appendix, a small organ located in the abdomen, had become useless when one switched from a leaf-based diet to a fruit-based diet. As a result, it was also thought that it was no longer useful and was only good for igniting in the event of an infection (also known as “good old family appendicitis”). However, this theory has recently been called into question: the appendix could be useful to the immune system by serving as a refuge for good bacteria in the digestive system. After a strong diarrhea that messed up the intestines and eliminated a good part of our intestinal flora, the good bacteria protected in the appendix could once again recolonize our digestive system. We must therefore see the organ as a reserve of good bacteria in the event of a glitch. That would explain why the appendix is ​​still useful, and thus why humans continue to have one. Well, after that, people live very well after it has been taken away from them, so the thing is not essential to our survival, but it is good to know.

7. If you have a long palmar tendon, know that it is useless

There’s a clue to whether a part of the body isn’t very useful: people are born without it. This is the case of the long palmar tendon, a tendon located in the forearm (visible when you press the thumb against the little finger) absent in a large part of the population. You may have it in one arm, if at all. The palmaris longus serves to flex the wrist, but it’s not the only muscle capable of doing this, so it’s lost its usefulness. Its presence or absence changes absolutely nothing in our lives, which explains why we can transmit it or not without this affecting the survival capacities of our descendants. It’s a little sad for him, but we’re not going to start feeling sorry for him.

8. The uvula is more useful to us than we think.

We’ve all wondered at least once what this ugly thing that hangs behind our palace was for. Well, the uvula isn’t just an ugly dangling thing: it’s used for swallowing and breathing by closing the nasopharynx. It is also used when speaking, because it makes it possible to articulate certain vibrating consonants such as the “r”. Without uvula, the songs of Brassens would have had a completely different face.

Top 10 explanations behind certain body parts now you know
Photo credits (Public Domain): Image of the American administration; French translation of texts by MetalGearLiquid

9. Eyebrows allow us to better recognize feelings

As you can imagine, if we have lost a good part of our facial hair (especially women) to keep only two lines of hair above the eyes, there is a good reason. And indeed, there is a good reason. The eyebrows protect our eyes from dust and other residues that could fall into them, but not only. They are also useful in facial recognition and the expression of feelings. Basically, studies have shown that people are better at recognizing emotions on the face of someone who has eyebrows than on the face of someone who doesn’t. This is perhaps why we always wonder if Philippe Etchebest is happy or angry.

10. If men have nipples, it’s because they have an X chromosome.

No need to be out of a big school to understand that nipples are useful for women. Without them, it is impossible to breastfeed the baby. Without them, we would not have come very far in evolution as mammals. But in humans, what is it for? Well nothing. If men have nipples, it’s just that the embryos all form the same way during the first 6 to 8 weeks of gestation. Basically, for 2 months, it is the X chromosome – common to men and women – which does all the work by starting to form the future living being. After this time, if it is a male embryo, the Y chromosome and testosterone begin to interfere and give masculine attributes to the future baby. But the nipples, which appeared during the first weeks, do not subside. They stay there, even if they are useless to men (which does not prevent them from being very nice erogenous zones). Something to remind us that we all come from pretty much the same mould.

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