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
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.