[retrac]

> Are we a result of similar microorganisms?

Many of the stages required to imagine how life went from solo and unicellular, to cooperative unicellular, to specialized unicellular verging on multicellular, to full-specialization unable to survive independently as a single cell, exists in some species or other today.

E.g. Dictyostelium is an amoeba. (Amoebas are not bacteria; they're eukaryotes like animals or fungi -- sexual reproduction and an encased nucleus.) Individual cells can survive independently, hunting for much smaller bacteria and nutrients. But in the presence of many other cells of its species, chemical communication occurs to trigger and guide cell differentiation. Some at the exterior of the cluster change into a protective shell, like skin, or a macro cell-wall. Others specialize into ion transfer between the interior and exterior environment. Some are even triggered to kill themselves during the reproductive phase, providing nutrients to their kin.

It's on the line between multicellular, and not. Parts can float off and re-join. I think something like that was the intermediate stage in the evolution of multicellular life like animals, but there's many other competing hypotheses and none seem to be universally accepted.