Pick an animal. Any animal. Somewhere in the world is a very special, carefully stored, individual of that species. Meticulously described, it is as well preserved as we can possibly make it. We’re trying to keep this one individual, above all others of it’s species, perfect.
It is what’s called the “Type Specimen”, and it is the chosen representative of its entire species. And we need one of these, for every single living thing, because if the world is going to be so very untidy, we at least need to be able to keep straight what it is we’re talking about.