There are many living beings that populate the Earth. The different types of animals and plants are probably the first that come to mind when we think of living things, but they are not the only ones: there are other creatures such as fungi or algae, and even many that are invisible to the naked eye, such as bacteria.
The latter are often a source of fear for the population, as they are associated with dangerous diseases, but the truth is that some of them are also part of our bodies and help us perform processes such as digestion.
When we speak of bacteria, we are talking about one of the main representatives of the monkey kingdom, according to the division into kingdoms of the different living beings. This kingdom, the oldest of all and the first to emerge as well as the most abundant, possesses a large number of unique properties that distinguish it from the rest of the kingdoms. That is why throughout this article we are going to talk about the main characteristics of the monastic kingdom , in order to understand how the forms of life that are usually included in this concept are.
What is the Monera Kingdom? A brief description
We call the monarchical kingdom a group of living beings classified in the same category due to the similarities between all its members and the differences with the rest of the group of living beings, following the classification in kingdoms proposed by Ernst Haeckel and later extended by various authors.
The monera kingdom groups together a wide range of unicellular beings without a cell nucleus , whose DNA is scattered in the cytoplasm and characterized by a great simplicity in its configuration (in fact monera comes from the Greek “moneres”, simple). This kingdom has traditionally been known as the kingdom of bacteria, which can be classified by their shape into coconuts if they resemble spheres, bacilli if they are shaped like a stick, spirilli if they resemble a ringlet or a spring, and vibrios if they are shaped like a coma.
However, it also includes the group of cyanobacteria, which differ from bacteria in that they are unicellular algae capable of photosynthesis, and the archaeobacteria (which have an internal functioning more similar to that of the rest of the kingdoms than to that of bacteria and are capable of surviving in the most extreme conditions).
Curiously, despite being probably the most primitive group phylogenetically speaking (they were the first inhabitants of the planet) and the one with the greatest presence in the world, it was the last one to be discovered (although not incorporated into the classification of the kingdoms, this honour corresponding to the fungi kingdom). It was incorporated as a kingdom of its own by Alexander Barkley in 1939 (although divided and later by Herbert Copeland as we know it today.
However, today the concept of the monarchical kingdom, and even the kingdom as a classification system, is increasingly in disuse . Furthermore, it has been observed that the representatives of the monera kingdom should be separated into two: archaea (including archaobacteria) and bacteria (including both bacteria and cyanobacteria), due to the great differences between these groups.
Main characteristics of the Monera Kingdom
As mentioned above, the monkey kingdom has a number of characteristics and peculiarities that have so far been classified as one of the main types of living beings. In this sense, we can highlight the following characteristics as the most relevant.
1. Prokaryotic organisms
One of the distinctive features of the monkey kingdom is that all of its representatives are prokaryotes, i.e. living beings that do not have a cell nucleus. Thus, the DNA is not condensed and protected by a structure , but is spread throughout the cytoplasm of the cell. It is the only one of the kingdoms that presents this characteristic, being the most primitive group of living beings.
2. Circular DNA
Linked in part to the previous point. If we think about DNA, the image of a double helix will surely come to mind, just as it happens in human DNA chains. However, in the monkey kingdom this type of distribution does not occur, but rather a structure in the form of a closed, circular double chain is presented. Interestingly, this structure is also found in the mitochondria of animals.
3. They are unicellular
While animals and plants are composed of millions of cells, moneras are much simpler organisms that are composed of a single cell . They do not form tissues or organs, nor do they need them to survive. Despite this, some specimens are grouped together in large groups (although they are still living beings at an individual level).
4. Asexual reproduction
Another characteristic of this kingdom is that all its components present mostly asexual reproduction and based on mitosis : bacteria reproduce through binary fission or bipartition, in which the same individual generates copies of its DNA and divides into identical and independent individuals, or gemination in which a miniature version of itself is generated on the body and grows until it is detached.
However, in some cases there is a genetic exchange with other bacteria, through contact or through the transformation of DNA within the being itself.
5. Displacement methods
Another aspect to take into account is that although some are immobile, in many cases the moneras can also be moved. This is because they can have scourges and cilia to which they can move by means of helical or front-to-back movement and vice versa.
The components of the monkey kingdom are the smallest creatures that exist (with the possible exception of viruses, if we consider them living beings), often no more than a few microns.
7. Feeding methods
Moneras can have different feeding systems. As a rule they are heterotrophic, that is, they feed on external elements or other creatures . In this sense they can be parasites, symbiotic or saprophytic (they feed on the waste of other beings).
However, many bacteria and all cyanobacteria are autotrophic, generating the nutrients needed to live from inorganic matter, such as through photosynthesis.
Most living things are aerobic, which means that they need oxygen to survive. However, in the monera kingdom there are specimens that can survive without oxygen (facultative anaerobes) or even for which oxygen is deadly (in fact, one of the first mass extinctions occurred among the obligatory anaerobic organisms when this element began to prevail in our atmosphere).
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- Margulis, L. and Schwartz, K. V. (1982). Five Kingdoms. An Illustrated Guide to the Phyla of Life on Earth. W.H.Freeman, San Francisco.
- Murat, D.; Byrne, M.; Komeili, A. (2010). Biología celular de los organelos procariotas… Cold Spring Harbor Perspectives in Biology 2(10). doi:10.1101/cshperspect.a000422.