Oxygen in living beings plays a highly relevant, often vital, role. Through the process known as respiration, oxygen allows a large number of organisms to be kept alive (British & Journal, 2017).
Breathing consists of the metabolic reactions that the cells perform to obtain energy. The organisms that require oxygen for this purpose are known as Aerobios; Those who are not, are called Anaerobes.
Oxygen Cycle
Oxygen also plays an important part in the chemical structure of most components of living things.
It is present in the most basic components such as carbohydrates, sugars, lipids and proteins.
Oxygen and energy in living things
In the aerobic organisms oxygen is necessary for the respiratory process and the obtaining of energy.
However for anaerobic organisms oxygen is not necessary and in many cases is toxic.
Although oxygen is essential for the survival of aerobic organisms, it can also be harmful.
Usually the breathing process generates reactive oxygen molecules that act as toxic substances in a process known as oxidative stress and that damages cells (Magenta, Dellambra, Ciarapica, & Capogrossi, 2016).
There are also organisms that, depending on the environmental conditions, may or may not use oxygen to obtain energy. These organisms are known as facultative.
Examples of organisms according to their use of oxygen.
Oxygen, photosynthesis and food
The production of oxygen is closely linked to the production of food for many living things.
In the photosynthesis , Organisms that use light as a source of energy produce organic compounds and oxygen (Caumette, Lebaron, & Matheron, 2011).
Organic compounds that are derived from photosynthesis are consumed by heterotrophic organisms, ie those that do not produce their own food. In many cases these heterotrophic organisms also consume oxygen.
Without the presence of oxygen, the process of photosynthesis would not take place as we know it and the food production of many living beings could not be carried out.
Oxygen in evolution.
Oxygen has been a main responsible for that life on earth is conformed by the organisms that exist today. In addition, it has influenced the way they get their nutrients and energy (Packard, 2017)
The presence of large amounts of oxygen in the atmosphere drove the proliferation of organisms that used oxygen to obtain energy. This selective pressure allowed the establishment of the flora and fauna that today inhabit the planet.
Evolutionarily, the presence of Mitochondria In some living beings it is allotted to an anaerobic cell with a nucleus that absorbed an aerobic cell.
The absorbed cell became the mitochondria allowing the appearance of organisms such as humans.
Oxygen promises to remain a decisive element in the evolution of life on earth.
Apart from the importance of their availability for food and metabolism of living beings, their well-known role in the planet's climate will define the forms of life that will survive (Decker & Kensal, 2011).
References
- British T. Breathing In Living Beings. BMJ. 2017; 1 (2254): 5-6.
- Caumette J. Lebaron P. Matheron R. (2011). Environmental Microbiology: Fundamentals and Applications.
- Decker H. Kensal E. Van H. (2011). Oxygen and the Evolution of Life. Springer.
- Magenta A. Dellambra E. Ciarapica R. Capogrossi M. Cell Calcium Oxidative stress, microRNAs and cytosolic calcium homeostasis. Cell Calcium . 2016; 60 (3), 207-217.
- Packard G. The Evolution of Air-Breathing in Paleozoic Gnathostome Fishes. Society for the Study of Evolution. 2017; 28 (2): 320-325.