The oldest signs of life on Earth are fossilized ancestors of these one-celled organisms
[DOC] [TLE] 4 The Origin and Early History of Life [PAR] The earliest fossils are of bacteria too small to see ... that explain how life may 
have originated on earth, but there is ... searchers is that life arose spontaneously 
from these early waters less .... complex, single-celled organisms called protists, 
have just ingested .... science of genomics, which suggests that the ancestors of.