A rudiment is an organ, the main meaning of which was lost in the process of evolutionary development of the organism. This concept also includes structures that are reduced and differ in lesser capabilities compared to the corresponding structures in other organisms. Rudimentary organs were thought to be completely useless, but many of them still perform some minor or relatively simple functions with structures that were most likely intended for more complex purposes.
Strange gifts of evolution
By the beginning of the 19th century, comparative anatomy, also known as comparative morphology, developed as an independent biological discipline that considers the general patterns of development and structure of organs by comparing various types of living beings at different stages of embryogenesis. She became the evidenceorigin of man from other representatives of the animal world. Anatomists have identified the same organs in different organisms, differing in size and shape. Cases of the complete absence of some of them or relatively poor development compared to the same organs in other species have been observed. Underdeveloped organs began to be called rudimentary (from Latin rudimentum - "initial stage, germ"). They appeared useless and on their way to extinction.
A rudiment is an organ that was laid in the course of embryonic development, but eventually ceased to develop. In adult forms, it later remained in an underdeveloped state. Similar organs or their parts can be found in almost every species of animals and plants. Compared to homologous (similar) structures of similar organisms, they are either underdeveloped or lack some important component.
There are similar organs in our body. So, for example, wisdom teeth are a vestige of a person. These are also such organs as the third eyelid, or the epicanthus, the coccyx, the vermiform appendix of the caecum, the muscles of the ears that determine their mobility, the hairline on the trunk, limbs. In total, there are more than 100 of them in the human body. They are the remains of those organs that had a fully developed appearance in the corresponding ancestral form.
Evidence of the historical development of the organic world
Vestigial organs as a result of any changes in the environment, in lifestyleof a certain species lost their importance for survival and gradually ceased to function. We should not forget about the constantly occurring mutations, which led to a decrease in the size of various organs, a weakening of their functions. In the case of their considerable importance for survival, organisms undergoing mutations were eliminated.
A structure that is in the process of elimination is referred to as a "rudiment". This is a kind of evolutionary process, which is based on mutations, hereditary changes in some individuals. In organisms with a slight development of the system of regulatory correlations (relationships), coadaptation of parts is slowly carried out. It takes place in the order of natural selection of more vital, harmonic ratios. This is a mutual regular functional adaptation in the course of the evolutionary transformation of any organs of one individual or their group, as well as various living creatures of the same biocenosis.
A similar example of a rudimentary human structure is the appendix (vermiform appendix). This is the remnant of a blind outgrowth that was once a large functioning organ in the digestive system of herbivores. Its functions are clear enough. Food rich in fiber requires a long time for digestion, a blind outgrowth is a place in which, with the participation of the microflora living in it, a gradual process of digestion of plant cellulose takes place. In the course of evolutionary development, our ancestors began to consume less fiber and more meat, which led to a gradual decrease in blind outgrowth. Heturned into a vestige, but far from useless. Its role in maintaining human immunity is quite significant. The appendix retains the original microflora of the large intestine, being an incubator for Escherichia coli. It is much more difficult for people with a remote appendix after suffering infectious diseases to return the intestinal microflora to normal. That is why the appendix is often called a kind of farm for the reproduction of beneficial microorganisms. There are claims that removing the appendix increases the risk of malignant neoplasms.
Animal Rudiments
In other living beings, many organs have also been identified that have lost their functions during the natural historical development of organisms and are on the way to extinction. These are, for example, bones located in the thickness of the abdominal muscles in pythons and whales, which are vestiges of the hind limbs. Eyes are a vestigial organ in animals that live in the dark. In wingless birds, these are the rudimentary wing bones. There are many organs that have lost their original meaning in plants. So, on the rhizomes of lily of the valley, couch grass, fern, scales were found, which are rudiments of leaves. In the marginal inflorescences of Compositae, under a magnifying glass, underdeveloped stamens are clearly visible. In the staminate flowers of the cucumber, the remains of the pistil, which is present in the center of the tubercle, is also a rudiment. These are all essential proofs of the historical development of the organic world.
Atavisms
Scientists also distinguish manifestations in certain individuals of signs that werecharacteristic of their distant ancestors, but absent from the closest representatives. Such manifestations are called atavisms. Their most characteristic examples are the caudal appendage, fistulas in the throat, overly pronounced hairline, the presence of additional pairs of mammary glands, and others. These traits, lost in the course of evolution, occur as a rare exception.
It should be noted that atavisms and rudiments are not identical concepts. Rudiments are present in all individuals of the species, they have certain functions. Atavisms are found only in some representatives and do not carry any functions. By the way, they should not be confused with developmental anomalies of a different nature, such as branched ribs, cleft lip, six-fingered phenomenon, and others.
All discovered rudiments and atavisms are signs corresponding to a certain stage in the development of the evolutionary tree. A clear proof of this is that organs that have become useless for the body can persist for a long period of time, gradually reducing and destroying further due to mutations.
In modern biological science and today the focus is on the study of the genome of living beings, including humans. Data on the origin of rudimentary organs will help answer one of the pressing questions about which genes are turned on or blocked during the development and reduction of rudimentary organs.
"Rudimentary organ" technique
The concept of a rudiment in a figurative sense as a relic of a disappeared phenomenonused in technology. There is a clear analogy with biological evolution in the development of technological progress. Here, too, rudiments are often referred to as parts of mechanisms, machines or other devices that have lost their meaning at the present stage of development of a particular system, but continued to be preserved in order to be compatible with previously accepted standards. Examples of rudiments in computer technology are a modem, a floppy drive. In automotive technology, the “rudimentary organ” is the ignition switch; in aviation, an automatic radio compass is such an example.
