Try reading the article Oh Braindead One.<quoted text>
The theory [common ancestor] specifically postulates that all of the earth's known biota are genealogically related, much in the same way that siblings or cousins are related to one another. Thus, universal common ancestry entails the transformation of one species into another and, consequently, macroevolutionary history and processes involving the origin of higher taxa.
A theory postulating is not a fact.
Where's your evidence of the, THE, common ancestor. You know, the first life where all other life came from.
It gives evidence and tests of how we know that all life is related.
You asked for evidence, I gave it to you. I did not think that you were intelligent enough to understand it. If you have specific questions I will be happy to help you to understand.
Now of course your request for "THE, common ancestor" (sic) shows that you have no understanding of evolution. You cannot debunk a theory that you do not understand.