Firstly before I answer, keep in mind how life originated and how the first cell came into being are matters of educated speculation, since these events cannot be reproduced in the laboratory, however, several experiments have given us a good idea. That's an inaccuracy of Evolution. Remember Evolution is an extensive process. The first cells are predicted to have arose 750,000,000 years after the formation of Earth. And I already addressed the idea that cells are the smallest iotas of life at a conventional level. The precedes and descendents of the first celled organisms aren't necessarily life for they are not defined as life.