The study of botany very properly begins with a few comments about the origin of life. How did life come about? We know there was a time when the planet had no life. Life may have begun nearly four billion years ago.
As we look around today, we are led to the conclusion that all life comes from previously existing life. Further, knowing that organisms are composed of cells, we concur with what Rudolf Virchow (1821-1902) said in 1858: that “all cells come from previously existing cells.” Our common sense tells us so.