Scientists are saying that microorganisms on rocks are probably the oldest living thing here on Earth. There is one in Australia and another one in Greenland that are both billion years old.
There is a set of filament-like fossils in Australia that are in rocks that are still preserved even up to this date. A microbial mat that gets its energy from the sun some 3.5 billion years ago still exist, reported in the journal Astrobiology in 2013. According to Live Science, there is also a set of rock in Greenland that might be the oldest thing on Earth. There was life 3.8-billion-year-old ago in rocks from Akilia Island, Greenland.
A 3.7-billion-year-old group of cyanobacteria fossils are said to be found in Greenland. These cyanobacteria are called stromatolites when they are in layered form. In 1996, scientists have reported that some mystery microbes have caused a metabolic activity to those rocks. However, this discovery is still debated on. It was reported in the journal Nature but both claims are still being discussed. Both claims are also true regarding Earth's oldest living organism.
There are also new speculations that before the extreme time on Earth, some 4 billion years ago or the Hadean period, there were also life that existed. Since, meteorites and asteroids are bombarding earth; it might have been destroyed before it was found out. "There is some skepticism, which is warranted," said University of California, Los Angeles, geochemist Elizabeth Bell in a SETI Talk in February 2016. Her team has found a zircon crystal with a different level of isotope that might implicate life on Earth during that time.
BBC has reported that Earth has been through many things before the life as we know it existed. It is 4.5 billion years old and it is still living and changing every day. In its first million years of existence, it has suffered from meteorites and other geologically violent events.
After some time, it ended and Earth formed its crust after it cooled down. The big islands or continents only existed after volcanic eruption and erosion happened. After some more billion years, Earth as we know it is now evolved into this.
