HELLO!
My dear fellow steemians, today I would like to talk about something that at obviously at one point of time has struck our mind. Yes, a typical question that one always is seeking answer for, 'How did life actually begin on earth?'
Lets find out!
Earth is estimated to be about 4.5 billion years old. But living beings seemingly didn't appear until 3.7 billion years ago. The earliest evidence for life on Earth comes from fossilized mats of Cyanobacteria called Stromatolites in Greenland. However,there are hints of life in even more primeval rocks: 4.1-billion-year-old zircons from Western Australia contain high amounts of a form of carbon typically used in biological processes.
Fossil of Stromatolites.
Scientists believe that complex organic molecules could come together and metabolize to form genetic molecules.
The origin of life.
An experiment designed by Stanley Miller and Harold C. Urey, in 1952, suggests that complex organic molecules might have formed under the conditions of early Earth.They believed the early Earth atmosphere would have been composed of methane, ammonia, hydrogen and water vapor. They sealed these gases in an airtight container, and then exposed the gases to sparks of electricity to simulate lightning. They continued the lightning for a week, and by the end, a reddish-brown substance had coated the walls of the container. These were a variety of amino acids in the resulting primordial soup. Its results have actually been confirmed many times by other scientists.
THE FIRST STEP: METABOLISM OR GENES?
While some scientists believe that complex organic molecules could come together and metabolize (a chemical process that sustains life) to form genetic molecules, some believe that genes were single molecules that had developed in such a way as to be able to catalyze their own replication.
THE SECOND STEP: GENE REPLICATION.
RNA is a complex organic molecule that can catalyze on its own to reproduce. Many scientists believe that simple RNA molecules developed and eventually became more complex and developed into the organisms we see today.
LUCA (Last Universal Common Ancestor)
Astrobiologists and biochemists search for traits that are common across all life forms and assume that any traits that are common to all life forms today must have been inherited from LUCA, who had them all as well.She was probably the ancestor of the three kingdoms of life: Archaea, Eukaryotes and Bacteria.
The tree of life.
Nonetheless, this could be only one of the million possible ways how live originated on Earth. Science still seems to be in pitch darkness about how life actually originated. However, scientist still believe that emergence of life is still possible. How? It is yet to be answered!
That's all for today.
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Until Next Time!
Credits:
www.livescience.com
https://lco.global/spacebook/how-did-life-start-earth/
Images: www.google.com