Here is an exclusion chunk that I currently use in my Unknowns only/ no Life url:
&without_taxon_id=48460%2C1126112%2C67333%2C131236%2C151817%2C48222
the 48460 number excludes all Life, and makes the later numbers redundant, but I keep those in so that I can adjust the focus with an easy edit. I forget what the other couple numbers do.
Edit: 1126112 was from some unrelated past issue and can be removed so
&without_taxon_id=48460%2C67333%2C131236%2C151817%2C48222