The origin of life on our planet is a mystery that until now has not been revealed with certainty and for several decades it has been filling people with uncertainty. scientists from many latitudes; Certainly all the theories point to an age of not less than 3.5 million years for the first forms of life, sharing the idea that these first manifestations of living beings on earth showed a basic form of development and interaction.
Various factors made the first inhabitants of our world to prosper and be successful, among which the most suitable forms of reproduction stand out, very frequent today in microorganisms but quite different from that of vertebrates and larger species.
This peculiar form of reproduction is the bipartition or binary fission, where the interrelation of two individuals of different sex is not necessary to share chromosomes, but the same unicellular individual has the ability to clone itself. Below we will show all the details of bipartition, a mode of reproduction that guaranteed the current existence of life.
Cellular division
The fundamental premise that governs reproduction through bipartition is that every cell can divide to form a new one, thus giving way to the regeneration of tissues that are essential for the survival and prosperity of the species.
Both in the sexual reproduction as asexual the process of cell division is key and very necessary because if it did not occur there would be no way to form a new individual; Very variable are the times and circumstances in which cell division occurs, from ten minutes to weeks it can take a cell to divide according to its type and conditions. Bipartition is the most exact cell division since two stem cells are exactly the same or at least with a high percentage of parity.
What organisms use bipartition?
This method of reproduction is exclusively used by unicellular organisms of microscopic dimensions, which, as we mentioned earlier, have inhabited our planet from the very beginning of life; among these particular living beings are:
The bacteria
They are a form of life that is managed through a single cell that fulfills the elementary functions of life such as being born, growing, feeding, reproducing and dying; These cells are of the prokaryotic type, that is, without a defined nucleus or membranous organs. Its size is tiny and can vary between 0.5 and 5 microns in wingspan; bacteria are very important in various decomposition processes as well as in the metabolic cycles of compounds such as methane.
The archaea
microorganisms that until recently were thought to be a type of bacteria due to their similar function and structure, however over time it was determined that they belonged to a totally different domain because their evolutionary principle and biological morphology is different.
Fission yeasts
They are rod-shaped fungi that have eukaryotic structures in their cell. It is the only yeast fungus that reproduces by bipartition.
Protozoon
They are single-celled organisms that thrive in the water or humid environment, are predators or autotrophs; It should be noted that not only do they reproduce asexually, but sometimes they share genetic material in a kind of sexual reproduction.
Types of bipartition
Oblique
It occurs specifically when a cell division begins as longitudinal and then passes to a phase between longitudinal and transversal, this modality can occur in opalinids, microorganisms that they benefit from living in the intestine of some amphibians and mollusks, with highly specialized cells that have multiple nuclei. Opalinids have oblique rows of cilia, which benefits this type of bipartition.
Transversal
They occur in some oval-shaped ciliated protozoa, less than a micron in size, and capable of feeding on bacteria and algae. Asexual reproduction occurs when the cytoplasm divides perpendicular to the axis of the spindle.
longitudinal
It occurs when the cell divides longitudinally rather than transversely. A clear example of this division is the flagellates, which have structures called flagella inside your body, characteristic of eukaryotic cells.
Regular
It is a symmetric division of a cell, which guarantees the creation of two cells of equal size and very similar characteristics, close to accuracy.
Other types of asexual reproduction
Not only is bipartition the viable method for the creation of a new living being from the asexual point of view, there are numerous types of reproduction through genes own the individualIn the following lines we will see some others that compete with binary fission.
Parthenogenesis
It is a process by which an ovum or female reproductive cell does not need to be explicitly fertilized to begin a stage of development and cell division that will give life to another being. This reproduction is triggered by certain factors such as hormonal cycles, stationary seasons and climatic conditions and it is seen in species such as insects, some lizards, amphibians, and in certain birds; in this cycle, the total absence of male chromosomes can be observed, intervening in genetic development
Polyembryony
It happens particularly when in the zygote or cell resulting from sexual reproduction, more than one embryo is created thanks to the fact that the original embryo is fragmented into many, which guarantees the success of the species with little male intervention. This type of reproduction is considered indirect sexual and is seen in insects and mammals including humans.
Sporulation
It uses elements called spores as a means of reproduction, which are designed in such a way that they disperse and reproduce in the environment, it will depend on correct climatic and humidity factors that these spores have the ability to form a new individual.
In some plants, fungi, algae and bacteria this type of reproduction is seen very frequently, but particularly in plants the process becomes more interesting because they can alternate without difficulty between pollination and sporulation.
Fragmentation
It is a form of reproduction where multicellular individuals divide themselves into several parts forming a new being, each of the resulting pieces has the ability to complete a development that leads to conversion to a specific organism. Earthworms, starfish and planarians are clear examples of this reproductive method.