Please note! This essay has been submitted by a student.
Prokaryotic and Eukaryotic symbiosis is like the difference between the first iPhone (released in 2007) and the current iPhone X (released in 2017). When the first iPhone was released, it was considered a good product that could hold its own against other competitors on the market. However, this same phone doesn’t even measure up when compared to the current iPhone X. The iPhone X comprises all of the best features of the previous iPhone generations and additional features that are completely new to the iPhone series. This helps to make the iPhone X a new and improved product for its users.
Before explaining the process of endosymbiosis and the evolution of eukaryotes, I would like to simplify the process by breaking down the origins of all eukaryotes. Eukaryotes are sort of a small speck in the big picture of symbiosis. They are descended from a chimeric organism that previously resided inside an alpha-protobacterium sort of like a set of Russian nesting dolls (Openstax, 2013). By having one cell encompass another cell or cells, the absorbed cell is able to thrive thereby turning the entire cell into a sort of super cell because both of the cells benefit from this cohabitation (Openstax, 2013). This allows the cell to reproduce and create generations of cells strengthened as a result of the diversity and unification of the previous cells.
The hypothesized steps for the evolution of eukaryotic cells via endosymbiosis are as follows:
There are features in the metabolic process in prokaryotes that don’t take place in the same process for eukaryotes. An example of this would be nitrogen fixation. However, aerobic respiration is found across the board for all of the main lineages of eukaryotes where it is found confined within the mitochondria (Openstax, 2013).We acknowledge the presence of aerobic respiration today because even though the atmosphere contains approximately one-fifth molecular oxygen (O2), scientific evidence has shown that there was a time when the atmosphere lacked oxygen (Openstax, 2013).
There came a point in time when prokaryotes started converting energy from the sun to fuel the anabolic stage to lessen carbon dioxide in order to form organic compounds, meaning that the prokaryotes evolved to create the ability to photosynthesize (Openstax, 2013). This evolution was helped along when hydrogen was taken from numerous sources and contained by using solar powered reactions to lessen secured carbon dioxide in the Calvin cycle (Openstax, 2013).
The result was that the photosynthesized oxygen expanded in some areas to levels that were potentially harmful to living organisms because of the damage it could cause to several organic compounds (Openstax, 2013). Eukaryotes are descended from a predecessor with mitochondria. This was noticed by light microscopists in the 1800s who realized that there was the appearance of movement within the cells suggesting that bacteria was residing within the host cells (Openstax, 2013). An example of light residing within the cells would be plastids. Plastids are an example of eukaryotic cells that utilize photosynthesis. Similar to mitochondria, chloroplasts also have endosymbiotic beginnings. Plastids are obtained from cyanobacteria that resided inside the cells of an ancestral, aerobic, heterotrophic eukaryote (Openstax, 2013). This is how it came to be discovered that one of the main differences between eukaryotes and prokaryotes was the presence of mitochondria and chloroplasts.
Mereschkowski posited that nucleus evolved from a prokaryote (mycomplasma), which was later absorbed by an amoeboid cell homologous to the eukaryotic cytosol (Martin, Garg, & Zimorski, 2015) Though many scientist would later arrive at a similar conclusion as Mereschkowski, few embraced his original suggestion (Martin, Garg, & Zimorski, 2015).
Overall, symbiosis is like having an adult who is fully capable of supporting themselves without assistance move into an ecovillage or a co-living situation. Yes, this person can survive on their own but certain factors such as the economy, social structures, and environment/living situation can negatively impact this individual’s quality of life. But by moving into a community with like-minded individuals all working towards a similar goal while also sharing a similar point of view, can be the beneficial living arrangement that will help this person to thrive due to now having a support system in place where none existed before.
Symbiosis is one of those win-win situation where there are more pros than cons due to the benefits both parties receive. We as a species owe our very existence to the process that is known as symbiosis. It is through this process that our genetic material was able to survive for us to be present in this form that we have come to accept as the human body.