Atavisms and human rudiments are examples. Vestigial organs and appendix

The difference between rudimentary and atavistic characteristics lies in which particular ancestors of a given individual - immediate or distant - one or another characteristic is observed, as well as whether it is the norm or a deviation.

Atavism

Atavism is a characteristic that was present in the evolutionary ancestors of a given species, but is now itself existing form it is not inherent. However, the genes encoding it remain and continue to be passed on from generation to generation. Under certain circumstances, these “dormant genes” can “wake up”, and then an individual with an atavistic trait is born.

For example, the tarpan, an extinct wild ancestor of horses, had stripe-like markings on its legs. Modern horses do not have them, but individuals with similar markings are occasionally born. At the beginning of the 19th century, the birth of such a foal from a horse, which 2 years earlier had been unsuccessfully mated with a male zebra, gave rise to the pseudoscientific theory of telegony.

Atavistic signs are also found in people. Sometimes people are born with continuous hair like apes, with additional mammary glands like those of monkeys, with an appendage in the form of a tail. Until the middle of the 20th century, such people had one way - to a fair booth or to a circus, to amuse the public with their unusual appearance.

Rudiment

A vestigial trait is also a legacy of evolutionary ancestors. But if atavism is the exception, rudiment is the rule.

Rudimentary organs degraded during evolution and lost their functionality, but they are present in all representatives of a given species, therefore, the birth of an individual with such a trait is not a deviation from the norm.

An example of a vestigial organ is the eyes of a mole: very small, practically invisible. However, moles are normally born with eyes; the birth of a mole without eyes is possible only as a result genetic abnormality or intrauterine development disorders.

An example of a vestigial organ in humans is the muscles surrounding auricle. They help other mammals move their ears to listen, but few people are capable of this. The rudiment is the coccyx - a degraded tail.

Homologous organs, which are prenatal period occur in everyone, but fully develop and function in individuals of only one sex - for example, underdeveloped mammary glands in men. Provisional organs, which exist only in embryos and subsequently disappear, should not be confused with rudiments.

According to the theory of evolution, humans descended from monkeys. For millions of years, due to this process, the appearance, character, and mental capabilities of Homo Sapiens changed, distancing it from its ancestors. era technical progress brought the human species to highest level evolutionary development. The presence of common ancestors with the animal world is now presented in the form of rudiments, examples of which will be discussed in this material.

Characteristic

Vestigial organs- certain parts of the body that have lost their original meaning during evolutionary development. Previously performing the leading functions of the body, now they carry out secondary functions. They are laid on initial stage embryonic formation, without fully developing. The rudiments are preserved throughout the life of the individual. The function that they carried during standard development is significantly weakened and lost in their ancestors. Modern world cannot fully explain the essence of the presence of such underdeveloped organs in the physiological structure.

Vestigial organs are the primary evidence of evolution for Charles Darwin, who spent many years observing the animal kingdom before coming to his revolutionary conclusion.

Such body parts directly confirm family ties between extinct and modern representatives of the planet, helping to establish the path historical development organisms. Natural selection, which serves as the basis, removes unnecessary traits while improving others.

Examples of rudiments among the animal world:

bird fibula;
presence of eyes in underground mammals;
residual hip bones, partial hairline cetaceans.

Rudiments of man

TO vestiges of man include the following:

coccyx;
wisdom teeth;
pyramidal abdominal muscle;
appendix;
ear muscles;
epicanthus;
blinking ventricle.

Important! Examples of rudiments different people are common. A few tribes and races have such organs, characteristic only of their species. Each example of rudiments in humans can be identified and described in detail to bring clarity to the topic under discussion.

Types of basic rudiments

Coccyx represents lower section spine, including several fused vertebrae. Function anterior section The organ serves to attach ligaments and muscles.

Thanks to it, there is a correct, uniform load on the pelvis. The coccyx is an example of a rudimentary tail in modern humans, which served as a center of balance.

Wisdom teeth - these are the most belated and obstinate bone formations oral cavity. The original function was to assist in the process of chewing hard, tough food.

Modern human meals include more thermally processed foods, so during evolution the organ has atrophied. Located last in the row, wisdom teeth often come out in people of a conscious age. A common phenomenon is the absence of “eights” and partial eruption.

Morganian ventricle- paired sac-like depressions located in the right and left parts of the larynx. The organs help create a resonant voice. Apparently, they helped the ancestors reproduce certain sounds, protect the larynx.

Appendix- vermiform appendage of the cecum. It helped distant ancestors digest rough food. Currently, its functions have diminished, but remain important role, which consists in concentrating the focus of formation of beneficial microorganisms. The presence of this organ in humans has a significant negative quality- possibility of inflammation. In this case, it needs to be removed surgically. The microflora after surgery is difficult to restore, and infectious diseases become more frequent.

Ear muscles also belong to the rudimentary features surrounding the human auricle. Ancient ancestors had the ability to move their ears, enhancing the hearing needed to avoid encounters with predators.

Attention! It is strongly not recommended to deliberately get rid of some of the listed organs, because they still perform secondary functions.

Vestigial organs of certain races

Epicanthus - vestigial vertical continuation the upper fold of the eye. Exact reasons And functional features of this organ are not thoroughly known. There are suggestions that skin fold protected my eyes from weather conditions. Characteristic of the Bushmen.

The pyramidalis abdominis muscle continues the list of vestigial organs, representing a triangular shape muscle tissue. The main function is to tighten the linea alba.

Steatopygia - fat accumulation V upper parts buttocks Has a storage role, like a camel's hump. Characteristic of some African tribes, although this rudiment or pathology is not fully understood.

Human atavisms and differences from rudiments

There are peculiar external signs kinship human species with the animal world. Atavism is a sign present among the ancestors, but not inherent in the current species.

Those who encode it are preserved, continuing to pass on its properties to the next generation. They can be called “sleeping”; they awaken only at the birth of individuals with an atavistic trait. This happens when genetic control is lost, or due to external stimulation.

The main difference between atavism serves as the manifestation of traits in individual individuals. Human individual during embryonic development partially follows the path of distant ancestors. At certain weeks, the embryos have gills and tail-like processes. If these signs persist during childbirth, they represent atavism.

Atavisms and rudiments alike serve as evidence theories of evolution, but if the first signs have no functions, then the second ones carry a certain useful value. Some types of this phenomenon can pose a threat to health or disrupt some vital processes. Some people still speculate on the topic: is the appendix a norm in the form of a vestigial organ or an atavism.

Attention! Many atavistic signs are easily removed surgically, making life easier for the wearer.

Examples of atavisms

Many people still confuse atavisms and rudiments, attributing one to the other. The first ones have two types of signs:

physiological;
reflexive.

Examples of human atavism should be thoroughly studied so that the difference becomes clearer.

If people do not exhibit external signs of one thing or another, this does not mean that the genes for the signs are absent, but have the ability to manifest themselves in the future.

Atavisms are extremely rare in the population and appear only in cases where ancient ancestral genes unexpectedly appear in humans.

Here are the most common and obvious types of human atavism, making up the following list:

excessive hairiness;
protruding tail;
cleft lip;
multiple nipples in humans;
second row of teeth;
hiccups;
grasp reflex in newborns.

The listed features clarify the debate among many about whether wisdom teeth, hidden or erupted, are a rudiment or an atavism. They are characteristic of many species, but not all occur. If wisdom teeth or other rudimentary parts of the body were found only in single specimens, then it would be possible classify them as atavism.

We study what rudiments are, examples

12 rudiments in humans

Conclusion

Homo Sapiens is a complex organism with a diverse system of life activity, changing millions of years of evolution. Everyone has examples of their types. The main difference between atavism and rudimentary body parts is that only a few possess them, and a person can easily live without them.

Atavisms and rudiments in humans are considered as one of the arguments of evolutionary theory. Body parts that were formed by ancestors modern people under pressure environment, but have now become unnecessary. Organs that have lost their original significance during the development of human evolution are called vestigial. , which were characteristic of distant ancestors, but were absent from close ones, is called atavism.

List of main rudiments:

ear muscles;
wisdom teeth;
coccyx;
appendix;
pyramidal muscle;
epicanthus.

Rudiments in modern man

The appendix is a remnant of an organ that human ancestors had digestive functions. The appendix can now protect against the loss of commensal bacteria that help the body digest. However, it probably also possessed this function among human ancestors.

The auricles are the temporoparietal, anterior and posterior muscles. They allow you to move different sides auricle. Modern man does without moving its ears, but in some representatives of the homosapiens species this ability is clearly expressed.

In modern monkeys, especially macaques, the ear muscles are much better developed. This is because primates use them to be alerted to danger. But the ear muscles of chimpanzees and orangutans, like those of humans, became minimally developed and non-functional, but did not completely disappear.

Wisdom teeth are designed to chew tough and solid food plant origin. It is believed that human ancestors had more powerful jaws, which gave them the ability to chew foliage. Chewing thoroughly compensated for the inability to digest cellulose, which was part of plant food. Changes in dietary patterns have led to naturally formed less strong jaws. But the wisdom teeth remained. In the new generation of people, wisdom teeth began to erupt less frequently, which confirms the evolutionary theory of rudiments. Due to the uselessness and even harmfulness of these parts of the body, there is a possibility surgical removal wisdom teeth

It's interesting that different nations The development of wisdom teeth does not coincide. The Tasmanian Aborigines preserved powerful jaws and well-developed wisdom teeth. In Mexico, on the contrary, they hardly grow.

Coccyx - remnant vestigial tail, which in different periods All mammals have developed. During prenatal development, the human fetus has a tail for about four weeks. It is most noticeable in embryos that are 31 to 35 days old. The tail bone, located at the end of the spine, has lost its importance in promoting balance and mobility. Now the coccyx remains important as an attachment point for muscles, tendons and ligaments. Sometimes a birth defect causes a person to have a short tail at birth.

Since 1884, there have been 23 reported cases of babies born with tails. In all other respects, these children were normal. All of them had their tails surgically removed, and these children continued normal human lives.

In the inner corner of the eye there is a small crease, a crescent fold. It is a remnant of the nictitating membrane, a translucent or transparent third eyelid that allows some animal species to keep the eye moist without losing visibility. In cats, seals, polar bears and camels, the nictitating membrane is completely preserved. Other mammals have only its rudiments.

Atavisms of modern people

During the months of his prenatal development, a person partially follows the evolutionary path of his ancestors. It is known that human embryos different weeks existences resemble the evolutionary ancestors of humans. In some cases, atavistic signs may persist in the born child.

Some genes that disappear phenotypically may not disappear from human DNA. They remain inactive for generations. Lack of genetic control can lead to rebirth in individual person dormant genes. It can also be caused by external stimulation.

One of the most bright examples atavism - hair. The common ancestors of humans and monkeys had bodies covered with thick hair. And today it happens that a person’s hair covers his entire body, leaving only the palms and soles of his feet smooth. It happens that both men and women have an extra pair of nipples - this is also a legacy of distant ancestors.

Sometimes microcephaly (small head with normal proportions of the rest of the body) is also considered an atavism. Usually this pathology is accompanied by a deficiency mental abilities person. Atavisms include cleft lip, anomaly human development, which they try to eliminate surgically.

Some human reflexes are also classified as atavisms. Hiccups are a legacy of amphibian ancestors. It helped pass water through the gill slits. Newborn humans have a grasping reflex. It is considered an atavism that people received from their primate ancestors. This is how baby monkeys grabbed onto the fur of their mothers.

Atavisms and rudiments have partially changed, and partially received new meaning. It can be observed that some rudiments die out among peoples in whose environment they become unnecessary, but are preserved among others where these parts of the body have not become vestigial.

Atavism (atavus, ancestor, great-grandfather) is a certain form of heredity in which a creature develops characteristics that are absent in the immediately preceding generation (father, mother). But characteristic of one of the previous generations (grandfather, grandmother, great-grandfather, etc.). In this article we will look at examples of atavisms in humans with photos, as well as examples of atavisms in animals. These characters therefore represent a return to an ancestor (Rückschlag, pas-en-arri-ere, reversion or throwing-back). And atavism is, therefore, heredity, transmitted intermittently through one or several generations. Various organic and functional features and all kinds of spiritual qualities can be transmitted. As well as a predisposition to disease.

A person most often experiences a return to his grandfather or grandmother, but returns to more distant ancestors are also common. But it is more difficult to prove them, since these ancestors have long since disappeared. Examples of atavisms in humans; in the photo they appear most clearly in cases mixed race. This or that individual of a later generation suddenly acquires typical features distant ancestor. Previously, atavism was explained by a special law of hidden heredity. Then they began to consider it a simple consequence of the so-called general biogenetic law, according to which each creature passes through its own individual development to a certain extent, the stages in which his ancestors were.

There are also several reflexes that are also classified as atavisms:

the newborn's grasping reflex - this is how baby monkeys grabbed their mother's fur
hiccups, which previously served in amphibians to pass water through the gill slits

One of the most common examples of the phenomena of atavism includes, for example, those cases when any individual of a domestic animal or plant resembles its wild form.

So, if we begin to propagate fruit plants not with cuttings or layering, but with seeds, we will get the original form.
U various breeds Among domestic pigeons, from time to time individuals appear that are similar to the parent species - the rock pigeon (Columba livia).

Here the return is obvious and can be either general or specific. But we also talk about atavism when an individual of a certain form has only one characteristic, long lost by this form. About which we know from the history of individual (ontogeny) or tribal (phylogeny) development that it characterized another, more ancient form.

Lion kittens are spotted at birth, but an adult lion is never spotted. There are, however, cats that remain spotted even in adulthood, hence the spottedness of a lion kitten is an atavistic phenomenon, indicating the latter’s origin from a more ancient spotted form.
Among the horses there are individuals that have dark rings on their legs: a return to some kind of zebra-like form. The same horse, occasionally, has hind hooves sitting on more developed slate (metacarpal) bones - an indication of origin from the three-toed type of horse, hipparion, of previous geological eras.

Provided development is stopped in any direction, it can always stop at some stage. Examples of atavisms in humans presented above in the photo and atavisms in animals have important in phylogenetic issues and represent one of the pillars of evolutionary teaching.

Human Vestige- a part of the body or an undeveloped organ that has lost its necessity due to changed conditions of existence, but is still present in the present time, without carrying any semantic load.

Availability rudiments in humans absolutely not conditioned by anything, but the existence vestigial organs continues to be passed down steadily from generation to generation.

The very first thing that comes to mind when discussing rudimentary human organs is coccyx. The coccyx in humans is formed by the fusion of several vertebrae (usually from 4 to 5).

There were times when the tailbone was part of the tail - an organ for maintaining balance, and it also served to give various signals, thereby expressing one’s emotions.

Over time, as man became an upright walking creature, the forelimbs gradually became free and took over many functions, including those performed by the tail, thus the tail lost its importance in the transmission of social signs and in maintaining balance, turning into vestigial human organ.

Appendix- vermiform appendix of the cecum, also is a vestige of man, performing absolutely no functions.

There is an opinion that the appendix used to serve for long-term digestion of solid food (for example, cereals). There is another opinion on this matter - the appendix served as a kind of reservoir and breeding ground for digestive bacteria.

Appendicitis is a disease in which the appendix (rudiment) becomes inflamed and has to be removed. This operation is very common.

Wisdom teeth They are so called because they sprout much later than other teeth, at the age when a person seems to become “wiser” - 16-30 years.

In most cases, wisdom teeth do not have enough space and they begin to bother, interfering with neighboring teeth and, like the appendix, they have to be removed, which allows us to confidently also attribute wisdom teeth to human vestiges.

Goosebumps- a very interesting protective function of the body, which has lost its relevance in relation to humans, but still exists to this day. Goosebumps appear when triggered pilomotor reflex, the main reasons for which are cold And danger.

When goosebumps appear, the hair on the body rises, which, by the way, also is a vestige of man, for the simple reason that it has lost any meaning and does not perform any useful functions.

One can cite many more different rudiments of a person, such as hair on the head, nails, toes, muscles that move the ears, and so on.

Atavism in humans- the appearance of certain characteristics that were characteristic of our distant ancestors, but are currently absent in others.

The main difference between atavism and human rudiment it is believed that atavism is a certain deviation that occurs in in rare cases, for example, abundant hair on the face or something like membranes between the fingers (very rare), and everyone has rudiments, they just lost their meaning over time

Let's look at hair, for example. They play an important role in the “work” of the skin. Near the hair follicle there are sweat and sebaceous glands. Excretory ducts parts of the sweat glands and most of the sebaceous glands come to the surface of the skin along with the hair. Sebum prevents the development of microorganisms, softens the skin and gives it elasticity. However, if a person’s entire body is covered with hair, including the face, then materialists call this pathology atavism and associate it with inheritance from distant ancestors. Why? Yes, because monkeys and many other animals are completely covered with hair - fur.