Some parts of our body do not perform anyfunctions in our body. It's all about evolution, which made them "superfluous." For example, the appendix is not an important part of the body, but some studies claim that this rudimentary process of the cecum contains bacteria that are beneficial to our gastrointestinal tract. Sometimes the appendix can be inflamed or even ruptured, which requires an immediate surgical operation to remove the organ. Some other parts of our bodies played an important role in the survival of our very distant ancestors, but over time they also became useless. Some of them can even be removed surgically, and their absence will not reduce the quality of human life.
Business Insider has talked toBoston College’s evolutionary anthropologist, Dorsa Amir, and learned more about what she herself calls “evolutionary remnants”. Here are 9 parts of the body that people have, despite the fact that they have not functioned for millions of years.
1. The appendix is the most famous useless organ.
Many, many years ago, an appendix participated indigestive process, helping to process rough, as well as plant foods rich in fiber. Many herbivores still use it in digestive processes, but it is no longer part of the human digestive system.
"With the transition to a more diverse food and, in particular, meat, people no longer need too long and complex intestinal tract," - says Amir.
At the same time, the appendix can not be called completelyuseless body. According to some studies, there are some beneficial intestinal bacteria in the appendix, but scientists have not yet figured out to the end - “whether it was always its function or the organ acquired it over time,” Amir adds.
2. Long palmar muscle from wrist to elbow. Approximately 10 percent of people, it generally appears.
If you put your hand on a flat surface with your palmup and close your thumb with your little finger, and then slightly lift your fingers, then a protruding ligament can be seen just below the wrist. This ligament is called the long palmar muscle. Amir says that earlier this muscle was used by our ancestors for climbing trees.
According to the British Encyclopedia, muscle,most likely helped in strengthening the grip when jumping, for example, from one tree to another. But when about 3.2 million years old, the ancestors of man began to walk on two legs, this muscle eventually lost its benefit.
“It has become useless for a very long time,” commented Amir.
About 10 percent of modern people have this muscle completely absent. At the same time, the strength of their grip is no different from those who have this muscle.
“Natural selection is a system that is not always aimed at perfect efficiency,” adds Amir.
3. People no longer need a very powerful jaw because their diet has shifted towards softer foods and processed foods.
Our jaws are smaller than our ancestors had. Because of this, there was a problem with the wisdom teeth, which was not enough space.
Today, not all have the so-called “eights”. This is due to the fact that earlier these teeth allowed our ancestors to chew on hard and hard food. Modern man consumes processed in some way products, so the need for these teeth disappeared.
“Considering the fact that today we eat soft food, and the molars were usually used to grind solid food, gradually the need for them began to disappear,” says Amir.
4. Arrector pili are muscle fibers that, when reduced, cause goose bumps or goosebumps.
It can manifest itself in a variety of situations: when you listen to your favorite music, watch your favorite movie, you are cold, scared, or, on the contrary, very good.
Our ancestors had thicker haircover and these muscle fibers perform a very useful function. In case of danger, this made our ancestors much more massive, which, in turn, could scare away the enemy.
In animals with dense fur arrector pilistill perform a useful function - help to retain more heat. In addition, as in the case of our ancestors, these fibers help with protection. For example, porcupines definitely benefit from them.
5. A human embryo develops a tail at 5-8 weeks.
By the time of birth, the tail disappears, leaving behind only a few rudimentary vertebrae intergrown between themselves, which form the tailbone.
Evolutionary theory tells us that our ancestorshad tails that helped them to balance, however, with the advent of the person's sensible skill of upright walking, the need for a tail disappeared, in fact, like the tail itself.
In medicine, there are cases of the birth of babies with more pronounced tails. This happens very rarely, but nonetheless occurs. Fortunately, surgeons can easily remove it during the operation.
6. The ear muscles surrounding the auricle were formerly actively used by our ancestors, but they do not perform any useful function in modern humans.
Other animals use these muscles to determine the danger or when catching prey. In addition, some types of animals use the movement of the ears for the expression of emotions.
The same cats, thanks to the ability to move the ears,have excellent hearing. Amir says that since the man in the course of evolution got a very plastic neck, he no longer needed to move his ears in the direction of the sound in order to better hear it.
Some people can still move their ears a little, but this doesn’t compare with what our ancestors were capable of.
7. The pyramidal muscle located in the lower abdomen has the shape of a triangle. People can have from zero to two such muscles, but there is no prok from them.
The pyramidal muscle can help squeeze the linea alba's white abdominal line, but is not related to the function of the abdominal muscles.
Approximately 20 percent of people do not have any pyramidal muscles.
eight. Fruits of male and female initially develop the same and only in the future the formation of male genital organs starts testosterone. However, the nipples begin to develop before this hormone begins to act.
Under natural conditions, men can notlactating, but this effect can cause high levels of prolactin, a hormone that helps produce milk. Lactation is a side effect of cardiac digoxin medication.
And although many male mammals in extreme situations can lactate, only the fruit bat dayak, found in Southeast Asia, lactates spontaneously.
9. The semilunar fold or the third eyelid is a fold of tissue in the inner corner of the eye.
It resembles the membranes that some animals (reptiles, birds, and certain mammals) use to protect their eyes.
“It’s not quite clear why people no longer have them. But in fact, they are rare among primates, so we must have lost them a long time ago, ”says Amir.
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