I suspect a biological imperative describes something that every member of a species has to do or have to survive to keep the species going. If we talk about a biological imperative with respect to the species itself, then not every member of the species need be involved. But would this require the biological existence of the species?
Here are two scenarios. The first I have no problem with. The second may require the existence of species.
First: Every member of our species needs oxygen to survive. So having oxygen is a biological imperative.
Second: Not every member of a species has to or can procreate. So procreation is not a biological imperative for members of a species. From the perspective of the species, procreation might be a biological imperative. However, doesn’t something have to biologically exist to have a biological imperative?
I suspect there are subtleties I am missing here which is why I am asking the question. Also I am trying to get more clarity on whether I should expect a species to actually exist and not simply be one label in a taxonomy.