Should we be forcing the world view of knowledge organization on our people (
various classification schemes, taxonomies and knowledge organization frameworks) versus letting them organize materials on their own and as they see fit (folksonomies)?
Schaefer says that his organization has a letter
scheme to describe species as GX (presumed extinct) or GH (possibly extinct) and then uses several other
classifications, such as G1 (critically imperiled)-- ranks also used by
various federal agencies.