mage: White chimneys and smokers on Eifuku.
Eifuku are two seamounts in the Pacific Ocean located in the Northern Mariana Islands. An unusual hydrothermal vent called "Champagne" produced droplets of liquid CO. Credit: This image is in the public domain.
The Earth is populated by millions of described and classified animal species (approximately 7.8 million), thousands of plant species (approximately 300,000), thousands of species of fungi (approximately 600,000), not to mention organisms. unicellular eukaryotes and bacteria.
We see that all these living species are adapted to their environment, that they develop, reproduce and die.
It was discovered that they are all made of organic matter (carbon-containing molecules). This organic matter is constructed from a collection of amino acids. All known living things are made up (with a few exceptions) of 22 different amino acids. These amino acids, associated in a precise order, form proteins, biological macromolecules present in all living cells. We also see that all living species have genetic material that contains instructions (DNA). They all need energy whatever the metabolic process (respiration, photosynthesis). They all follow a process of continuous change over time (genetic mutations, diversity).
These common characteristics are proof that all living species are united by a kinship bond, a common ancestor.
The main hypotheses about the origin of life on Earth are classified into two categories:
- Early Earth hypotheses suggest that the first life forms appeared on Earth in the environment that existed early in the planet's history, 4.54 billion years ago.
- Panspermia hypotheses suggest that life exists in the universe and was brought to Earth from space by meteorites, comets or interstellar dust.
The white smoker theory is one of many hypotheses about the origin of life. It is plausible that life appeared in the depths of the oceans, under conditions that are still present today.
According to this theory, the first forms of life appeared on Earth at the bottom of the oceans, around hydrothermal vents which emit hot, mineral-rich fluids. This environment surrounding white smokers would have favored the emergence of life. Indeed, hydrothermal sources provide all the ingredients that life needs to start (energy, water, complex organic molecules). These three essential conditions could have existed in a stable, constant and invariable environment for millions of years. The permanent supply of minerals by hydrothermal vents and the mixing of constantly renewed molecules by the movements of water would have favored the emergence of life.
Life would have started by occasional, accidental, contingent molecular assemblies, sheltered from ultraviolet rays and cosmic radiation. In this stable environment provided by white smokers for millions of years, the increasingly complex organic molecules resulted in amino acids which are the building blocks of life. Then, always occasionally, accidentally and contingently, various protocells were able to form until they led by natural selection to cells, then to microorganisms.
In summary, white smokers (hydrothermal vents) are stable environments rich in nutrients, including water, reactive chemicals, carbon, nitrogen and phosphorus, all constantly replenished. In addition, they provide a permanent source of energy, in the form of heat and fluid movements.
White smokers have a basic pH, between 9 and 10 and a temperature between 40 and 75 degrees Celsius, unlike black smokers who have an acidic pH, between 1 and 3 and a temperature between 350 and 400 degrees Celsius.
It is for all these reasons that the White Smokers' theory of the origin of life is a hypothesis widely accepted by the scientific community.