9 body parts that humans don't really need

Evolution is a rather slow process, it takes millions of years. Organisms gradually acquire useful traits and lose unnecessary ones. But sometimes the traces of the latter do not disappear. This is how rudiments appear - parts of the body that are no longer used.G. B. Müller. Vestigial organs and structures / Encyclopedia of Evolution for its intended purpose, but also do not interfere.

Many animals, like dogs, have extra fingers. They are not needed when walking and are located far from the paw. And the whales have preservedJ. P. Dines, E. Otárola-Castillo, P. Ralph et al. Sexual selection targets cetacean pelvic bones / Evolution the pelvic bones of the hind limbs, which are very small and not even united with the rest of the skeleton.

People also have a lot of rudiments. Here are the most interesting ones.

1. Darwin's tubercle

Some people have in the upper part of the earO. Rubio, V. Galera, M. C. Alonso. Anthropological study of ear tubercles in a Spanish sample / HOMO slight thickening - Darwin's tubercle. It does not bring any benefit, it just reminds us that our distant ancestors - monkeys - had pointed ears. Tubercle transmitted with genes. For example, he meetsT. Y. Loh, P. R. Cohen. Darwin's Tubercle: Review of a Unique Congenital Anomaly / Dermatology and Therapy 40% of Indians and only 10.5% of Spaniards.

Charles Darwin was the first to list this feature as a rudiment. Only he called it differently - the Woolner's top, in honor of the English sculptor Thomas Woolner, on whose work he saw that very tubercle.

2. Ear muscles

The muscles that are near the ear and are attached to it, too, in fact, have lost their original purpose. Our ears have become smaller, harder and "pressed" to the head. As a result, we have forgotten how to rotate and move them towards the sound source like animals - we have to turn our head.

But the muscles remained and, as recently found outD. J. Strauss, F. I. Corona-Strauss, A. Schroeer et al. Vestigial auriculomotor activity indicates the direction of auditory attention in humans / eLife German researchers may contract involuntarily. With the help of this, according to scientists, they show us the direction of sound, in order, for example, to warn of danger. And you can also develop these muscles and learn to move a little. ears.

3. Appendix

In herbivores, the appendix is ​​a fairly large process that extends from the cecum and helps digest rough food. For example, raw plant shoots.

But we abandoned such a diet: we expanded the diet and learned how to process food. Therefore, in humans, the appendix (appendix) is not involved in digestion. It is comparatively smallR. R. Bollinger, A. S. Barbas, E. L. Bush et al. Biofilms in the large bowel suggest an apparent function of the human vermiform appendix / Journal of Theoretical Biology Is a small pouch 5–10 cm long and 0.5–1 cm wide.

However, the appendix cannot be called completely useless. It is known 1. R. R. Bollinger, A. S. Barbas, E. L. Bush et al. Biofilms in the large bowel suggest an apparent function of the human vermiform appendix / Journal of Theoretical Biology
2. H. F. Smith, R. E. Fisher, M. L. Everett et al. Comparative anatomy and phylogenetic distribution of the mammalian cecal appendix / Journal of Evolutionary Biologythat it serves as a container and incubator for intestinal bacteria that are involved in the digestion of food. The appendix helps to quickly restore microflora after illness, poisoning or antibiotic treatment.

The emergence of new features and the fact that the appendix canJ. Misdraji, F. M. Graeme-Cook. Miscellaneous conditions of the appendix / Seminars in Diagnostic Pathology give your owner a lot of trouble (from appendicitis before cancer), makes some scientists doubt that this is a rudiment.

Opponents of this point of view emphasize that its main purpose - the digestion of food - has nevertheless lost the appendix. The end in this scientific dispute has not yet been put.

4. Coccyx

This bone, consisting of several accrete vertebrae below the back, is nothing more than a remnantM. Nakatsukasa. Acquisition of bipedalism: the Miocene hominoid record and modern analogues for bipedal protohominids / Journal of Anatomy tail. He no longer helps us jump trees, but he can bring a lot of problems if unsuccessful fell and break it down.

Nevertheless, the coccyx still has a function: many pelvic floor muscles are attached to it, including those responsible for the genitourinary system, anus and buttocks. However, these muscles are also attached to stronger bones, such as the pelvic bones. Therefore, the removal of the rudiment practically does not leadE. P. Miranda, A. L. Anderson, A. S. Dosanjh et al. Successful management of recurrent coccygeal hernia with the de-epithelialised rectus abdominis musculocutaneous flap / Journal of Plastic, Reconstructive and Aesthetic to unpleasant consequences. The only risk associated with this is the development of infections and inguinal herniawhich rarely happens.

5. Wisdom teeth

Their eruption can be painful. And the third molars themselves, or "eights", as wisdom teeth are also called, canJ. W. Friedman. The Prophylactic Extraction of Third Molars: A Public Health Hazard / American Journal of Public Health press on the jaw if it comes out unevenly, and also lead to inflammation and caries. Because of this, sometimes they have to be deleted, which is not very pleasant.

This is how we pay offP. W. Lucas. Facial dwarfing and dental crowding in relation to diet / International Congress Series for the transition to a different diet and an increase in the brain. When people began to eat softer and more processed foods instead of harsh and coarse ones, they simply did not need extra chewing teeth. And the jaw was reduced to free up additional space for the brain.

So now wisdom teeth there is simply nowhere to grow. Therefore, if they nevertheless erupt, then they often bring problems. However, as long as they are healthy and do not interfere, it is betterGuidance on the Extraction of Wisdom Teeth. Technology appraisal guidance / NICE do not delete them.

6. Crescent fold

In the inner corners of the eye (those near the nose), you can see a small film that hides the tubercle. It's allWhy do cats have an inner eyelid as well as outer ones? / Scientific Americanwhat is left to us from the third century, or the blinking membrane. Some mammals, birds, reptiles and fish have it. The third eyelid is translucent and helps, for example, to swim under water with open eyes, to protect them from foreign objects.

The lunate fold cannot do this. But it cannot be called absolutely useless. It is necessary for the drainage of tear fluid and allows the eyes to rotate better.

7. Nipples in men

Nipples are needed to feed babies, but men don't. And yet they have the organ for this.

This is because the mammary glands appear in all embryos. But in the fifth week of pregnancy, when theN. Swaminathan. Strange but True: Males Can Lactate / Scientific American sex differences cease to develop in boys. As a result, men are born with nipples that will never be used for their intended purpose. Most likely.

The fact is that men are still capable ofR. D. Rohn. Galactorrhea in the adolescent / Journal of Adolescent Health Care lactate. Scientifically, the symptom is calledGalactorrhea / Mayo Clinic galactorrhea. During it, a milky liquid spontaneously emerges from the nipples. In men, this can be due to testosterone deficiency and be accompanied by breast enlargement and pain in it.

8. Palmar muscle

People's lifestyles have changed, and we just don't need a lot of muscles. For example, a long palmar helped our ancestors climb trees and hang on branches for a long time. Some primates, like orangutans, still use it.

But not people. Therefore, she no longer meetsS. J. Sebastin, M. E. Puhaindran, A. Y. T. Lim, et al. The Prevalence of Absence of the Palmaris Longus - A Study in a Chinese Population and a Review of the Literature / Journal of Hand Surgery in about 15% of representatives of Homo sapiens. If you're wondering if you still have this vestige, connect the pads of your thumb and ring fingers and bend your hand slightly.

Found it? Congratulations! However, keep in mind that the long palmar muscle does not give any advantages, for example, a stronger grip on the hand.S. J. Sebastin, A. Y. Lim, W. H. Bee et al. Does the absence of the palmaris longus affect grip and pinch strength? / Journal of Hand Surgery.

9. Body hair

Short thin and sparse hairs are all that a person has left from fur. It allows animals to control their body temperature. But people didn't need it.

There isWhat is the latest theory of why humans lost their body hair? Why are we the only hairless primate? / Scientific American different hypotheses explaining why this happened. Perhaps the ancestors of people lived near water and wool, which got wet and dried for a long time, began to interfere with them. Perhaps this is how the body tried to get rid of parasites, which were many in long hair. Or maybe the fur, which protects animals from the scorching sun, has become unnecessary due to the fact that people began to walk on two legs. Most of the body has simply ceased to be exposed to direct sunlight.

However, we did not become completely naked. Probably because, having lost the main function, body hair saved additional. For example, with their help it is easier to notice that crawling along the leg or armI. Dean and M. T. Siva-Jothy. Human fine body hair enhances ectoparasite detection / Biology Letters some kind of parasite.

One of the rudimentary human reflexes is also associated with hair. In moments of stress or when we are freezing, we may develop the so-called goose bumps: hair bumps heave, and the hair itself stands on end. Responsible for this reactionH. Fujiwara, M. Ferreira, G. Donati et al. The Basement Membrane of Hair Follicle Stem Cells Is a Muscle Cell Niche / Cell tiny arrector pili muscles that connect the follicles to the skin.

In animals, wool rises from a similar reaction. This is necessary to scare off the enemy, becoming visually larger, or to make the hairline thicker and warm.

But since we have almost no wool left, a person during an adrenaline rush or when coldly reminds him of a plucked goose.