The oldest signs of life on Earth are fossilized ancestors of these one-celled organisms
... gets to 
the split that separates the ancestors of plants from the ancestors of animals, ... 
We know that the eukaryotic cell is of ancient origin, but we do not yet know the... [DOC] [TLE] Oldest Known Fossils Discovered: 3.7 Billion Year Old Fossils ... [PAR] Sep 3, 2016 ...