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Is it always rudimentary - is it unnecessary?

In the literary use of rudimentary - it came from the past, rebelled from oblivion. The word "rudiment" in a non-biological context means a relic of a phenomenon that has long since disappeared.

The Word in the Scientific Literature

Rudimentary is an adjective, which in biology and medicine is used to describe a part of a body or organ that has lost its original meaning. The function performed by this body at the present stage of historical development of the species is not significant, and it itself is close to extinction.

The catch is that it's rare to say for sure whether this organ is rudimentary or not. After all, the morphology of the organ, even if it is simply arranged or small, does not indicate its progressiveness or rudimentaryness.

Some features of the use of the term

In French scientific sources this adjective occurs in the sense of "arising", that is, rudimentary, but with the prospect of development, and not fading. In turn, this meaning is transferred to the organs that arise in phylogeny (in English and American sources), which means that there is a rudimentary one - it is incipient, contrary to the generally accepted meaning of the concept.

Rudiments in humans

Some formations and organs in the evolutionary development of the species lose their function, it becomes unnecessary in the changed conditions of life.

But it can not be said that the vestigial organs became useless, they rather changed their function. Examples are given in the table.

Rudiment

Former function

Modern function

Coccyx

Coordination of movements

Securing muscles and ligaments, correct distribution of load on the pelvic girdle

Worm-like process (appendix)

Digestion of plant fiber from unprocessed food

Place of multiplication of symbiotic bacteria, production of hormones, vitamin K

Body hair

Body warming, skin protection

Participation in thermoregulation, an obstacle to diaper rash in places of accumulation of sweat glands (axillary cavities, inguinal folds)

"Wisdom teeth"

Rubbing rough unprocessed food

Replacement of large molars in case of loss

Epiphysis

It is considered the remainder of the structure of the visual tract

The most important regulatory body that affects the functioning of the glands

On the other hand, the ear muscles or the fold of the epicanthus do not now perform significant functions in the human body.

Rudiments and Atavisms

Both of these concepts occur as evidence of evolution. They are often confused, because these are, in fact, different facets of the same phenomena. Rudiments, as mentioned above, are underdeveloped or in an embryonic state, but are characteristic of all individuals of the species. Atavisms are rare and represent a rudiment that has developed to the full (tail, hair on the face of a person).

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