Rudiment is an organ whose primary meaning has been lost in the process of evolutionary development of the body. Structures that are reduced and differ in lesser abilities as compared with the corresponding structures in other organisms also fall under this concept. It was believed that the rudimentary organs are completely useless, but many of them still perform some insignificant or relatively simple functions with the help of structures most likely designed for more complex purposes.
Strange Evolution Gifts
By the beginning of the 19th century, comparative anatomy, also known as comparative morphology, developed as an independent biological discipline, considering the general laws of the development and structure of organs by comparing various types of living creatures at different stages of embryogenesis. It has become the evidence base of the origin of man from other representatives of the animal world. Anatomists revealed the same organs in different organisms, differing in size and shape. Cases of the complete absence of some of them or relatively poor development in comparison with the same organs in other species were noted. Underdeveloped organs began to be called rudimentary (from lat. Rudimentum - "initial stage, embryo"). They seemed useless and on the path to extinction.
Rudiment is an organ that was laid in the course of embryonic development, but ceased to develop over time. In adult forms, later on he remained in an underdeveloped state. Similar organs or parts thereof can be found in almost every species of animals and plants. Compared with homologous (similar) structures of close organisms, they are either underdeveloped or lack any important component.
There are similar organs in our body. For example, wisdom teeth are the rudiment of man. it also organs such as the third eyelid, or epicanthus, tailbone, appendix of the caecum, ear muscles that determine their mobility, hairline on the trunk, extremities. In total, in the human body they can be counted more than 100. They are the remains of those organs that, in the corresponding ancestral form, had a fully developed appearance.
Evidence of the historical development of the organic world
The rudimentary organs as a result of any changes in the environment, in the lifestyle of 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, weakening of their functions. In the case of their considerable importance for survival, mutating organisms were eliminated.
The structure in the process of elimination is referred to the concept of "vestigial". it peculiar the evolutionary process, which is based on mutations, the hereditary changes of some individuals. In organisms with a slight development of the system of regulatory correlations (relationships), parts are co-adapted. It takes place in the order of natural selection of more vital, harmonious relationships. This is a mutual logical functional adaptation during 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 human rudimentary structure is the appendix (appendix). This is the remainder of the blind outgrowth, which was once a large functioning organ in the digestive system of herbivores. Its functions are clear enough. Fiber-rich food takes a long time to digest, blind growth is a place in which, with the participation of the microflora in it, a gradual process of digesting plant cellulose takes place. During evolutionary development, our ancestors began to use less fiber, and more meat, which led to a gradual decrease in blind growth. It has become a rudiment, but far from useless. Its role in maintaining human immunity is quite significant. Appendix preserves the original microflora of the colon, as an incubator of E. coli. It is much more difficult for people with a remote appendix after suffering an infectious disease to return the intestinal microflora to normal. That is why the vermiform appendix is often called a kind of farm for the propagation of beneficial microorganisms. There are allegations that removal of the appendix increases the risk of malignant neoplasms.
Rudiments in animals
Other living beings have also identified many organs that have lost their functions during the logical historical development of organisms and are on the way to extinction. These, for example, are located in the thickness of the abdominal muscles of the bones of pythons and whales, which are the rudiments of the hind limbs. The rudimentary organ in animals living in the dark are the eyes. In wingless birds, these are the rudimentary bones of the wing. A lot of organs that have lost their original meaning, and in plants. So, on the rhizomes of lily of the valley, wheatgrass, and fern, scales were discovered that are rudiments of leaves. In marginal inflorescences of Compositae under the magnifying glass, underdeveloped stamens are clearly visible. In cucumber stamen flowers, the pestle residue, which is present in the center of the tubercle, is also a rudiment. This is all significant evidence of the historical development of the organic world.
Atavisms
Scientists also identify manifestations in certain individuals of signs that were characteristic of their distant ancestors, but are absent in the nearest representatives. Similar manifestations are called atavisms. Their most typical examples are a caudate appendage, fistulas in the throat, excessively expressed hair, the presence of additional pairs of mammary glands and others. These features, lost during evolution, are encountered 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; certain functions are inherent in them. 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, the phenomenon of six-fingered, and others.
All discovered rudiments and atavisms are signs corresponding to a certain stage of development of the evolutionary tree. Clear evidence of this is that organs that have become useless for the body can persist for a long period of time, gradually reducing and collapsing in the future due to mutations.
In modern biological science, today the focus is on the study of the genome of living creatures, including humans. Data on the origin of vestigial organs will help answer one of the pressing questions about which genes are turned on or blocked during the development and reduction of embryonic organs.
"Rudimentary organ" in technology
The concept of vestigial in figurative meaning as a relic of a disappeared phenomenon is also used in technology. In the development of technological progress, there is a clear analogy with biological evolution. Here, rudiments are also 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 adopted standards. Examples of rudiments in computer technology are a modem, floppy drive. In automotive engineering, the “vestigial organ" is the ignition switch, in aviation an automatic radio compass is such an example.