he is confusing multicellular life and prokaryotes/eukaryotes,(reply>), @Kmykzy exactly who's to say on another planet all organisms are without mitochondria? (Or chloroplasts) they might have a prokaryotic cell structure, there might even be large, intelligent multicellular organisms without mitochondria.,(reply>)," If you are talking about <a href=""https://www.youtube.com/watch?v=Gfr50f6ZBvo&amp;t=1h35m37s"">1:35:37</a>", I think he is referring to multicellular specifically for the case of the mitochondria + host cell endosymbiotic assumed event, creating a multicellular unit witch we simply classify as a different type of cell when in reality its a bunch of cells in very close symbiosis, and not the normal definition of multicellular that just considers mitochondria a part of the host cell.<br><br>Btw, karyos only refers to the nucleus, there can be multicellular prokaryotes and unicellular eukaryotes, and weirdly enough there are indicators that non-mitochondria eukaryotes exist too. <br>But yes, if you are referring to the ideea of nucleus being a different cell than the rest of the cell then indeed, the cell nucleus evolution is also similar to that of mitochondria where most models suggest it was also formed from an endosymbiotic assumed event but compared to mitochondria there are also models that suggest evolving from some form of a virus capture or even internal changes that led to compartmentalization where as for the mitochondria witch is mostly agreed upon to have been from a separate cell with its own personal mitochondrial dna.