All life on earth originates from one single cell that was formed
more than three and a half billion years ago. This original cell
divided itself and formed two cells. The two cells divided themselves
and formed four cells,eight cells, sixteen cells, thirty two cells...
All life forms are really one huge organism, a super organism.
http://news.nationalgeographic.com/news/2010/05/100513-science-evolution-darwin-single-ancestor/