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We Must Thank This Bacteria For Our Existence

Photo Credits by: armennano on

What is Cyanobacteria?

Cyanobacteria are a phylum of gram-negative bacteria that obtain energy via a process called photosynthesis. There are over 2000 species across 150 genera

of many sizes and shapes. Similar to plants, cyanobacteria use photosynthetic pigments such as carotenoids, phycobilins, and several forms of chlorophyll. When compared to prokaryotes, cyanobacteria have internal membranes that are believed to be the reason for the eventual rise of specialized organelles.

How Could These Guys Be The Reason For Our Existence?

When Earth formed approximately 4.5 billion years ago, had a reducing environment composed of carbon dioxide, methane, and water vapor. When compared to today, our atmosphere is primarily nitrogen and oxygen. Water vapor was split by sunlight and resulted in oxygen and hydrogen, however, these atoms would immediately react with methane and be deposited into the earth's crust.

The immediate reaction left little traces of an oxygen-rich atmosphere. It was not until a random bacteria arose to change the earth's composition.

Thank You


It is believed that the first living organisms hit the scene around 3.8 billion years ago Since oxygen was absent at the time, it is likely that life on Earth had a metabolism that was anaerobic. Around 2.7 billion years ago, cyanobacteria evolved and became a major contribution to the origin of life study.

Cyanobacteria played an important role in the evolution of the Early Earth and its biosphere. This was due to the cyanobacteria's ability to release oxygen, thus changing the atmospheric composition, the rise of aerobic metabolism, and the evolution of multicellularity.

This series of events is sometimes referred to as "The Great Oxidation Event". The release of oxygen led to the evolution of other complex organisms that now depend on oxygen. With the ability to perform photosynthesis, cyanobacteria possess the machinery needed to oxidize water and use it as a fuel source. The oxygen released into the seawater and the atmosphere for the past 200-300 million years reacted with methane and later displaced it. Oxygen became the major component of the atmosphere and led to a change in Earth's chemistry.

Fast forward millions of years and we see the rise of multicellular organisms and the explosion of odd and complex organisms. All of this is thanks to cyanobacteria!


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