What was the beginner of life on earth?
It is not possible to give specific years in these approximations.
They are presented in a few ( 2 or 3 ) significant digits only, with
unit of time as 1 million/billion years ( my/by ). The experimental
dating is subject to imitations, in precision.
Before oxygen appeared, oldest growing and dividing microbes
might have appeared. This could be called the beginner of life on
The Earth had the first whiff of oxygen, 3.4 billion years ago ( bya ).
The Great Oxidation Event ( GOE ). that triggered oxygen into the
atmosphere, might have occurred 2.13 bya.
Unicellular life became extant during 2 bya - 600 mya.
Unicellular to multicellular life evolution might have started after 2