STRATIFICATION: MEANING AND TYPES - DUDAS - 2025

The word stratification comes from the verb stratify, and it means to divide or arrange into strata, which refer to layers or levels. Stratification can occur in different areas. It always refers to this differentiation by parts and it applies to very different areas, which can range from sociology, geology or even medicine.

The word "stratum" comes from the Latin "stratum", which means "bed", "bed cover" or "cobblestone", and the Dictionary of the Royal Spanish Academy indicates several definitions of stratum.

Source Pixabay.com

On the one hand, it defines the strata as elements that ended up being integrated thanks to certain common components and that form an entity, a fact or even a language.

Thus then it can be defined at a general level, but the word stratum is applicable to different areas or branches. Let's see.

Social stratification

It is neither more nor less than the order of social classes, although it is possible to go deeper than the classic upper, middle and lower classes. In each of the strata, it is made up of a group of people who share one of the social bands because they have similar values, styles and acts of life.

Although the basis of stratification is the level of income and possessions, one can also be formed based on age, ethnicity, and gender.

Of course, with the passage of time, the way of dividing society changed significantly. For example, in ancient times the division was between master and slave. Later they began to differentiate themselves by castes, which were groups of people whose belonging to one or the other was according to ethnic factors.

Then came the turn of the society of estates, which had a fairly broad definition, less clear for its members and determined by the social functions that each had.

At present, the division of social strata is based on classes, which base their positions according to economic income or properties and are arranged in upper, middle and lower class. Unlike the previous one, the members of each of its layers are very clear to which they belong.

Stratify a terrain

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This is about how the soil is composed in its different layers, made up of rocks, minerals, water and air bubbles. Thus, in the soil there are solid elements (clays, sand and remains of living beings), liquids (mineral salts and water) and gaseous.

In the outermost or superficial layer is clay, sand, air or humus. As one descends, there are increasingly larger fragments of rocks and pieces of it, while the amount of living beings present decreases until they are absent in the deepest stratum.

Each of these layers or strata are also called "horizons", and they go from W to E, from the most superficial to the deepest of the earth.

Aquatic stratification

It is the way that waters have to organize themselves in different layers according to their density and depending on external factors. Among the causes of these differentiations are the physical agents (temperature) and those of their composition (solid elements in suspension or dissolved).

This is very clear in lakes located in very cold areas during winter, whose surface freezes due to the very low outside temperatures, while below that layer the water is liquid and the deeper it is gained, the higher its temperature will be.

Stratification of the cornea

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Unlike dogs and other species that have a cornea composed of four layers, in humans as well as primates, the cornea consists of six layers:

Corneal epithelium

The epithelium is a tissue made up of closely knit cells that covers some internal tissues of the body from the outside. In this case, it is the most anterior part of the cornea and represents 10% of its composition.

This in turn is divided into four layers: squamous cell layers (disperses and retains the tear film), winged cell layers (promotes growth), basement membrane and basal layer (gives greater adherence to the Browman's layer).

Browman stratum

It is made up mostly of irregularly organized collagen fibers. With a thickness of 14 micrometers, its function is to protect the corneal stroma.

Corneal stroma

It represents 90% of the structure of the cornea, it is made up of 80% water (the rest of solid materials) and it has 200 sheets. The collagen fibers that compose it are separated from each other by the same distance from each other and give the cornea transparency.

Cloak of Dua

Separate the last row of keratocytes on the cornea. Its discovery is quite recent, given that its existence was proposed in a 2013 scientific publication by Harmider Dua.

Posterior (or Descement's) basement membrane

It is like a base membrane of the posterior epithelium, it lacks cells and its thickness varies with the passage of time, more precisely every ten years.

Corneal endothelium

It is a single layer that has an arrangement similar to that of a honeycomb. It is in permanent contact with aqueous humor (colorless liquid that nourishes and oxygenates the structures of the eyeball) and the anterior chamber of the eye (between the cornea and the iris).

References

1. Ines Martin-Lecave. (2005). "Practical Atlas of Histology". Recovered from: books.google.mk
2. Ing. Agr. Miguel Scalone Echave. (2012). "Morphology of soils". Recovered from: fing.edu.uy
3. Strata. (2019). Dictionary of the Royal Spanish Academy. Recovered from: dle.rae.es
4. Camilo Sémbler. (2006). "Social stratification and social classes: an analytical review of the middle sectors". Recovered from: books.google.mk
5. Rodolfo Stavenhagen (1969). "Social classes in agrarian societies." Recovered from: books.google.mk