Earliest known life forms

A life form is an entity or being that lives. Earth remains the only known place in the universe that is a refuge for life. It is estimated that more than 99% of all species of life forms, numbering more than five million species that have ever lived on Earth, have become extinct.

Some estimates of today's number of living species of life forms on Earth range from 10,000,000 to 14,000,000, of which approximately 1.2 million have been documented and more than 86 percent have not yet been described. However, according to scientific data cited in May 2016, an estimated 1 trillion species are now on Earth, and only one thousandth of a percent is described. The total number of DNA base pairs on Earth is estimated to be 5.0 x 10 37 with a total weight of 5,000,000,000 tons. For comparison, the total mass of the biosphere is estimated to be as much as 4 TtC (trillion tons of carbon). In July 2016, scientists reported the discovery of a kit with 355 genes from the last universal common ancestor ( LUCA ) of all organisms living on Earth. The Earth’s biosphere includes soil, thermal waters, rocks up to 19 km or more in depth, the deepest parts of the ocean, and less than 64 km of atmospheric height. In certain research conditions, the existence of life forms was observed in conditions close to zero gravity in space and survival in a vacuum in outer space. Life forms, as it turned out, exist in the Mariana Trench, the deepest place in the days of the oceans. Other researchers have reported relevant studies showing the survival of life forms in solid rocks up to 580 m below the seabed at a depth of 2590 m. In the ocean off the coast northwest of the United States, as well as at a depth of 2400 m under the ocean bottom of Japan . In August 2014, scientists confirmed the existence of life forms living under the Antarctic glacier at a depth of 800 m. According to the trail of one of the researchers, “You can find microorganisms everywhere - they are very adapted to the conditions and survive wherever they are. "

For most studies of the origin of life, fossil remains are the evidence. The age of the Earth is approximately 4.54 billion years. The first irrefutable evidence of life on Earth is at least 3.5 billion years old. There is evidence that life began to exist much earlier.

In 2017, there was a report of the presence of fossilized microorganisms in hydrothermal source sediments in the Nuvuagittuk Belt in Quebec, Canada, which may be 4.28 billion years old, suggesting an “almost simultaneous emergence of life” after the formation of the ocean 4.41 billions of years ago, and not much time after the formation of the Earth 4.54 billion years ago. In December 2017, scientists from the United States discovered microscopic fossils in Australia, estimated at 3.5 billion years old. These are the oldest known traces of life on the planet.

• Extraterrestrial life