There is a single-celled creature that has the power to change the world

How will you see when you know there is a single-celled creature but almost destroys life on Earth? Sounds ridiculous but very convincing! How convincing is it, please read on. It created the first Great Extinction in Earth's history and paved the way for complex multicellularity later on. So what are they and how did they do that?

They are the cyanobacteria , a simple, non-organism, organelles that have created a key chapter in the history of life on Earth. The Earth's atmosphere is not always rich in oxygen like it is today. At about 3.5 billion years ago, the atmosphere was all about nitrogen, CO ₂ and methane. Gaseous oxygen is rare and most are in molecular form like water. The ocean at that time contained all anaerobic bacteria, simple, single-celled, unrelated organisms without oxygen.

However, about 2.5 to 3.5 billion years ago, one of these microorganisms - the ancestors of known cyanobacteria - developed a new ability, which is photosynthesis. They take energy from sunlight to convert CO2 and water into oxygen to create energy.

The blue color is due to chlorophyll to help them absorb sunlight. Photosynthesis helps bacteria grow stronger and bigger than other bacteria. They can produce energy from an infinite source, so they grow very fast and increase dramatically in quantity. From here, the process of 'poisoning' other bacteria begins with the release of more and more oxygen.

At first, oxygen created chemical reactions with iron and other compounds, but after several hundred million years, the amount of oxygen produced more and more, faster than the reaction with other substances should gradually be accumulated. atmospheric accumulation, causing great trouble for the remaining bacteria on Earth - these microbes see oxygen-rich air as a poison and consequently the first major extinction of about 2.5 billion years before, except for cyanobacteria.

The problem does not stop there. Atmospheric methane is the cause of the greenhouse effect to keep the Earth warm at that time, but excess oxygen reacts with methane to form CO2 and water reduces the ability to retain heat. And also because the first and longest ice age, known as the "Huron Ice Age" begins. The Earth is like a giant snow ball for several hundred million years and once again, life is almost extinct.

But fortunately, aerobic bacteria begin to adapt and know how to use oxygen to create energy, excess oxygen is gradually converted. The amount of oxygen increases and decreases to a balance of approximately 21% today. Oxygen is highly applicable, so the ability to use oxygen helps organisms quickly diversify and evolve into more complex species. Cyanobacteria also contribute to that.

Hundreds of millions of years ago, some prehistoric bacteria swallowed cyanobacteria, which is called endosymbiotic. It is the ancestor of plant cells, cyanobacteria that become chloroplasts and organelles that carry out photosynthetic functions of plants today.

Cyanobacteria still exist everywhere on Earth: oceans, water, soil, . They still release oxygen into the air and take nitrogen to fertilize plants. Without them, there will be no life but because of them, life on Earth is almost destroyed.

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