The way in which prokaryotes like bacteria and eukaryotes like most multicellular organisms handle their genomes is part of this - prokaryotes are much more pro

The way in which prokaryotes like bacteria and eukaryotes like most multicellular organisms handle their genomes is part of this - prokaryotes are much more promiscuous in taking up and emitting genetic material, which is part of how you get so many different variants of the same "species" of bacteria, whereas eukaryotes are much more protective of their genomes and rely more on variable gene expression (in other words, which parts of the genome are going to be uncovered and available to read), rather than changes in the genome, to determine how they behave and what they "do". One thing that I think is sharply underappreciated is how much cross-talk there is within bacterial communities as is - it's a normal state of affairs for a full metabolic pathway to span between multiple species (so, one bacterial species takes the starting molecule, performs a set of transformations, emits it into the environment, a second species takes up that derived material, modifies it further, re-emits it, and a third species, or even the first species again, takes it up and continues the chain). A bacteria has a cell wall, but that's a tool used as part of many of the bacteria's function, which means you really need to look at a bacteria's "zone of influence" inside and outside the cell wall to understand what it's doing. So, given the flexibility of prokaryotic genomes, I think a bacterial colony containing multiple species or multiple variants of the same species might really be the prokaryotic equivalent of a multicellular organism, in which case they're absolutely everywhere, to a degree where focusing in on a single species of bacteria in any given context might be as reductive as focusing in on a single variant of human cell while evaluating how humans function.