Question

What are the three lines of fossil evidence that point to an early origin of life on earth and how do they tell us when life arose?

Answer 1

I believe you are referring to Bacteria, Archaea, and Eukarya as the first domains of discovered organisms that are posited to be the first. Residue of organic evidence of one of these forms have been found within geologic deposits that have been dated to 3.8 bya in Greenland. Actual fossil evidence of first organisms have been found in geologic layers that date to 3.5 bya in Australia, suggesting wide divergence of deposition.

They do not tell us how life arose because it is believed that plate tectonics have almost totally removed all evidence of first organic creatures, deposits and residue, making the 3.5 bya evidence of possible singular source.

Even more significant, no naturalistic process has been found that can explain the progressive increasing complexity of biochemical compounds needed for a living entity. Chemical evolution is a myth, like Darwin's "warm little ponds" and Oparin-Haldane prebiotic soup.