1. Meta-evolution happens as part of evolution, there's a logical "strange loop" there.
2. We see the kinds of macroscopic evolution among multicellular species that we do (such as the "choice" of having separate species, or the "choice" of having death-and-birth) not because it's somehow impossible to be otherwise, but because these modes of life have meta-evolutionary adaptive advantage.
When I contrast "Darwinian" vs. "Lamarckian" evolution I mean that the former does not have "inheritance of acquired traits" while the latter does. I might be using the term "Darwinian" in a non-standard way and I apologize if so.
When I'm talking about not being able to differentiate the two modes or kinds of evolution in the case of microorganisms, all I'm saying is that there's one process that has aspects of both modes.
Isn't what you just described about LGT obviously "Lamarckian" in the sense that a bacteria acquires a trait from "eating" a plasmid, incorporating it into its own genome, then dividing and passing the trait on to each offspring? I guess what I'm asking is, what do you mean by Darwinian?
Skipped LGT because it required multiple sentences being written on my phone. It is a misconception that bacteria /decide/ to take up or release plasmids into the environment. They don’t, it is a simple statistical process. F a bacteria is in an environment where there is a selective pressure that favors expressing a given gene (or group)then the bacteria that have those genes increases its proportional presence in the population pool. Now those bacteria have become dominant because of a particular set of genes, which means those genes are being expressed at a significant rate. Expressing the genes requires duplicating that section of the bacteria’s genome, and moving it of to the protein build molecules. So now we have an huge (proportional) amount of floating snippets of genetic material for the useful genes. That structure of these molecules tends to them wanting to connect their dangling ends, so many of them do just that (all expressed genes do can end up doing this, it is simply the selective pressure that increases the rate of expression).
Now as time goes by some of the bacteria will just die, and when their cell wall collapses any remaining genetic material just ends up floating in the environment. The most stable are those without dangling ends - the plasmids. The plasmids can also just escape through the wall generally - there is some ability for a bacteria to get rid of waste : ion pumps do the work, but there’s a limit to the size, which is why bacteria cannot simply get rid of all waste - the net result is that an environment in which a given set of genes is useful starts to accumulate plasmids that contain those genes.
For absorption of the plasmids, that is simply a product of how bacteria absorb all materials, so now the plasmid is inside another bacteria. In the event of any error by the when it cuts the plasmid it can end up including the plasmid material in its own genome