Endosymbiotic theory

The cooperation is an important aspect not only in humans but also in the components that are part of the body of living beings, without it, life would not be as it is now known. In this case we refer to cells . If cells did not organize together and cooperate with each other, the evolution of life forms would have been practically impossible .

What does it consist of

The endosymbiotic theory is a type of unified theory which is widely accepted that talks about how emerged organelles within the organisms , making a difference between prokaryotes of eukaryotic . In endosymbiotic theory, which is at the same time consistent with general evolutionary theory , all organisms arose from a single common ancestor . He refers that over time, bacteria have evolved in terms of their shape and function.

Characteristics of the endosymbiotic theory

Among the main characteristics that can be observed in the endosymbiotic theory, the following are mentioned:

• In this theory chloroplasts and mitochondria managed to evolve from bacteria .
• According to the theory, mitochondria had arisen 2 billion years ago from aerobic bacteria .
• It presents a system of ” englobing ” of eukaryotic cells.
• It states that mitochondria and chloroplasts were previously free-living prokaryotic organisms .
• Basically it says that an organism can get to dwell on the inside of another.
• He speculates that mitochondria came from proteobacteria and that plastids originated from cyanobacteria .

History

In 1883 , Andreas Schimper was the first scientist to study and describe the possible endosymbiotic nature of cells. In 1905 , Konstantin Mereschkowsky first suggested the idea that plastids had their origin as endosymbionts and was the first to manage to formulate the idea of ​​symbiogenesis, as the main driving force of evolution .

In fact, the American biologist Ivan Wallin was the first scientist to suggest the idea that the eukaryotic cell was made up of a series of microorganisms . In 1927 , several explanations also emerged as to how bacteria could be the main cause of the origin of species . In this way, the creation of a species could happen through the process known as endosymbiosis.

Ivan Wallin would work in conjunction with KS Mereschkowsky to form the idea of symbiogenesis , however, their theories were rejected as scientists disagreed with the assumption that mitochondria and chloroplasts did not contain DNA.

In 1981 , Dr. Lynn Margulis became the main figure behind the endosymbiotic hypothesis when she published her work Symbiosis in Cell Evolution . His research was the main support for the endosymbiotic theory; in which it is stated that in the beginning mitochondria were separate organisms that originally entered into a symbiotic relationship with eukaryotic cells through endosymbiosis.

Margulis managed to show that free-living bacteria and other microorganisms have a tendency to fuse with more specialized life forms quite frequently. When examining prokaryotes, eukaryotes and organelles, he claimed that endosymbiosis was the best explanation to explain why they were similar. Many important scientists before its advance, in the late 20th century, also contributed to the complete formation of the theory.

Who developed the endosymbiotic theory

As mentioned above, several scientists were involved in the formulation and development of the theory. It is considered that the first men who formulated the theories were Andreas Schimper and Konstantin Mereschkowsky and later, Dr. Lynn Margulis was in charge of putting all the pieces together to publish the theory. Actually, she had the role of putting the pieces together but it was actually a joint work.

Explanation

The endosymbiotic theory is an explanation that is given about the appearance of eukaryotic cells in the human body . This theory was not simple and many times it was also denied because it was previously had the idea that eukaryotic cells came from various changes that occurred gradually in the membranes.

It was established with it that the union of prokaryotic cells occurred slowly and progressively where one of them phagocytosed another while making it part of it, originated the different organelles and structures that a eukaryotic cell had . In other words we can say that is the process by which a cell is achieved by introducing into the inside of another cell and thus manages to get a lot of benefits through symbiosis .

This theory follows three processes known as incorporations which are mentioned below:

• First incorporation : this step indicates that a cell that can use heat and sulfur as an energy source can join a swimming bacterium and that through this symbiosis the ability to mobilize several eukaryotic cells can be given thanks to flagella and to the cell membrane that gives them more stability .
• Second addition: says that an anaerobic cell , for which oxygen was toxic, needed help to adapt to new environments. It postulates the union of aerobic prokaryotic cells in the internal part of a cell considered as anaerobic and thus explains the way in which peroxisome organelles and mitochondria appeared .
• Third incorporation : refers that the new aerobic cells carry out an endosymbiosis process with a prokaryotic cell which can carry out the photosynthesis process to give rise to the organelles of the plant cells, in this case the chloroplasts and that in this way they are originates the vegetable kingdom .

Importance of endosymbiotic theory

Endosymbiosis is important because it is a theory that manages to explain the origin of chloroplasts and mitochondria . Also because it is a theory that explains how eukaryotic cells arose . At present, this theory is only partially accepted as it contains some points in which scientists are in favor, however, it continues to present a series of doubts and contradictions.