I think it could be handy as some sort of evolutionary examples in some cases.
Things like having a few, preferably related, species of worms, or any other organism, that are obligatory parasites in one end of the spectrum, and free-living in the other, with a couple of intermediary stages in between, like "facultative" parasitism, and perhaps being not-so-well adapted to a wider range of hosts, versus being very specialized into parasitizing a given host species.
And, as a semi-parallel question, would there be known cases of organisms that apparently have evolved from parasite to free-living non-parasite, which I guess would be exceptions to the rule?
Things like having a few, preferably related, species of worms, or any other organism, that are obligatory parasites in one end of the spectrum, and free-living in the other, with a couple of intermediary stages in between, like "facultative" parasitism, and perhaps being not-so-well adapted to a wider range of hosts, versus being very specialized into parasitizing a given host species.
And, as a semi-parallel question, would there be known cases of organisms that apparently have evolved from parasite to free-living non-parasite, which I guess would be exceptions to the rule?