An Encyclopaedia of Life, cataloguing all 1.8 million plants and animals on Earth, is to be unveiled by scientists.
I have enough difficulty keeping records for my local patch

and can not imagine what a task it will be to cover the whole planet

.
I remember reading an article a few years ago (I can't remember where) which suggested that there are 1000s of species that have lived and become extinct before we even recognised them. Then there are the quite regular announcements of species "new to science".
Best of luck to all those invovled in this huge but worthwhile project.
Every life form on Earth to be catalogued - Telegraph
Richard