Ebrius Disputatios

The Ecosystems Of Early Earth May Have Been The Key To Life On Other Planets.

The most ancient ancestor of all life on Earth is considered to be LUKA (last universal common ancestor). A recent study by a team of British scientists has shed light on this ancient organism, revealing that it was remarkably similar to modern bacteria. Moreover, LUCA lived in a complex ecosystem, virtually no traces of which have survived to this day.

LUKA existed about 4.2 billion years ago, during a period when our planet experienced extreme conditions. The Earth did not look like paradise then: it was a boiling volcanic mass, bombarded by giant meteorites. About 100 million years before the appearance of LUK, a catastrophic cosmic collision occurred, as a result of which the Moon was formed. This period was called “Hadean” – after the Greek god of the underworld Hades.

LUKA's striking similarity to modern microorganisms suggests that life could have arisen almost as soon as the right conditions appeared on the planet. This suggests that life in the Universe may not be a rare phenomenon, but rather an inevitable process on planets with suitable characteristics.

LUKA as the basis of evolution LUKA represents a key point where the three major domains of life converge: eukaryotes (including animals, plants and fungi), bacteria and archaea. For a long time it was believed that LUKA lived 3.5–3.8 billion years ago, but new research has pushed this date back even further.

A recent study by a team from the University of Bristol found that LUKA existed 4.2 billion years ago, at the very beginning of Earth's history. There was no oxygen on the planet back then, and the atmosphere contained large amounts of carbon dioxide and methane, which likely gave the sky an orange tint. The Earth was covered in oceans and days were only 12 hours long due to the planet's faster rotation. The moon was closer to the Earth, which caused strong tides.

How LUKA survived Analysis shows that LUKA possessed complex enzymes that allowed it to extract carbon dioxide and hydrogen from its environment. It could live near the surface of the ocean, using gases from the atmosphere, or near hydrothermal vents in the depths of the sea, where hot water and gases erupted from the bowels of the Earth. These springs are considered one of the likely places where life originated.

LUKA was most likely a chemoautotroph, that is, it could independently synthesize the necessary substances from inorganic compounds. However, it could also be a heterotroph, dependent on compounds created by other organisms. Its developed metabolism indicates that LUCA has already come a long way in evolution.

Interaction with other organisms LUKA did not live alone: ​​his metabolism created a breeding ground for other microorganisms. For example, some of them could process methane, returning carbon and hydrogen to the environment. Research suggests that LUCA was part of a community that included organisms that used sulfur or iron from hydrothermal vents.

Additionally, LUKA had a semblance of an immune system reminiscent of CRISPR-Cas, a mechanism that today helps bacteria defend against viruses. This suggests that viruses existed even then and may have played an important role in the ecosystem by helping the exchange of genetic material between organisms. This process, called horizontal gene transfer, may have helped accelerate the emergence of diversity.

Cosmic consequences If LUKA is indeed 4.2 billion years old, it casts doubt on the theory that life is extremely rare in the universe. Rather, it may be common on planets with liquid water, such as early Mars or Venus. Astronomers have already found evidence of the existence of many Earth-like planets, raising the possibility of life beyond our planet.

Earth's unique features—such as a magnetic field that shields solar radiation and a large moon that produces tides—may have played a key role in preserving life. But if ecosystems like Gaev’s can be widespread, then the discovery of other biospheres is only a matter of time.