I don't think you understand what I'm saying. You can arbitrarily create models of earth life that didn't have a common ancestor via "my" hypotheticals which ar

I don't think you understand what I'm saying. You can arbitrarily create models of earth life that didn't have a common ancestor via "my" hypotheticals which are just as valid as univeral common ancestor (which predominantly features: there is something common in all life, so all life must have came from the same place; obviously this is a gross oversimplification but that's what we're dealing with in the answer)