Introduction
It is not hard to imagine how scientifically improbable the composition of our atmosphere is. This composition has enabled life on Earth to evolve and thrive for over 4 billion years. One of the most essential components of our atmosphere – oxygen, fuels the biochemical reactions that are integral for all life on Earth. Interestingly, oxygen makes up just 21% of our atmosphere while the rest is nitrogen and other trace gases. However, oxygen did not just spontaneously appear on earth.
How Oxygen Appeared on Earth – The Great Oxygenation Event
One of the most important geo-biological events in the history of the Earth was the Great Oxygenation Event, also called the “Great Oxidation Event” or GOE. It occurred during the Paleo-proterozoic era about 2.3 billion years ago. This event marks the point in time where primitive life forms such as cyanobacteria began to produce significant amounts of oxygen, which then began to accumulate in the oceans and atmosphere through the process of photosynthesis. This event is one of the most major contributing factors for the evolution of multicellular lifeforms. Interestingly, this event was also responsible for causing an early mass extinction, where many species of anaerobic microbes died out because of the ever-increasing oxygen content in the oceans and atmosphere.
Oxygen is Required to Turn Food into Energy
The energy we get from food comes from a process called cellular respiration. Cellular respiration is required to generate ATP, the energy currency of the cell. An organelle called the mitochondria is responsible for this process, whereby it breaks down glucose into a usable fuel source.
Physiological Processes Needs Oxygen
Studies have shown that without enough oxygen to the brain, cognitive functions break down, which can cause problems with your memory, analytical thinking, language abilities, and more. This is intriguing as the brain makes up just 2% of the total body weight but uses around 20% of the body’s total oxygen consumption. Moreover, the effects of low oxygen levels in other parts of the body can be life-threatening. Chronic breathing problems, strokes, and heart attacks can occur in severe cases. Low oxygen levels are caused by poor air quality or altitude change. High levels of carbon dioxide in the bloodstream can also cause low oxygen levels in the body.
In Conclusion
Oxygen is necessary for the body’s metabolic functions and it is paramount for the process of cellular respiration. In this process, carbohydrates and fats are broken down in a series of chemical reactions that release energy, which our cells use to produce ATP. This process can only happen with oxygen, so without it, we would not be able to survive. Moreover, a lack of oxygen, especially during strenuous exercise, renders the body incapable of using calories from food for the production of energy. This causes a buildup of lactic acid in muscles and other tissues, which can lead to cramps, headaches, and nausea. Explore more fascinating topics from nitrogen cycle and oxygen cycle to evolution and mass extinctions, only on BYJU’S Biology.
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