From studying biodiversity to protecting endangered species, an authoritative list would be massively helpful.

"Currently no single, agreed list of species is available.".

Yet there's still a lot of discussion and debate about what kind of criteria should be used for listing species on such a unified list.

A species having its name on a list matters – just like it matters who is on a school register or a guest list for a music gig.

"But it's an important step in managing and conserving all the world's species, great and small, for this and future generations."