Sounds like advanced symbiosis. I wonder if the movement is across a gradient or whether the super organism has a control unit that makes decisions. 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.
I think the answer to your question is probably "yes." I listened to an interesting show on PBS radio 30 Oct. about what happened 2Byo that jump-started evolution. I can't find the show online, which explained in depth, but this short and patronizing video[1] covers the gist of it.
I'm no biologist, but from what I've read: Probably not. A really important fact about multicellular life is that each cell is genetically identical to any other cell in the organism. Otherwise, different cells will start competing with one another, until the relationship falls apart. In nature, symbiosis only works because each cell has an independent means of reproduction, and that always puts a limit to how close the cooperation can be (nothing close to forming multicellular life).
Maybe that statement should come with an explicit topological constraint on the meaning of “inside” the body. Viewed as a donut, gut contents would be considered “outside.”
> In nature, symbiosis only works because each cell has an independent means of reproduction, and that always puts a limit to how close the cooperation can be (nothing close to forming multicellular life)
Mitochondria is its own organism, has its own DNA that is separate and distinct from nuclear DNA. It has been very successful through very close cooperation.[0]
True, though largely limited to DNA necessary for its functions. I don’t have a citation on me (mobile) but there’s evidence that more “generic” mitochondrial DNA was integrated into the nuclear DNA, and that this is also the case for other endosymbionts.
I have a hypothesis for why this happens. Sexual reproduction has a very neat property: Recombination. Two individuals that each have one harmful mutation can through recombination have offspring without either of them. This allows removal of harmful mutations from the gene pool without terminating someones entire lineage - important when every generation comes with a decade of mutations, unlike microorganisms that are more on the scale of hours or days. However mitochondrial DNA cannot recombine, so it cannot benefit from this mechanism. Therefore it makes sense to move as much DNA as possible from the mitochondria to the nucleus. The same goes for the Y-chromosome, and could explain why it has been losing genes over time at a truly astounding pace.
> In the last 190 million years, the number of genes on the Y has plummeted from more than 1,000 to roughly 50, a loss of more than 95 percent.
I'd think it's quite likely. This also somewhat happens at animal scale FYI. See "colonial organisms" such as zooids / siphonophores, which consist of multiple separate animals that are able to join and work in together and take on specialized roles to form and behave as one larger animal.
