Just say for the moment that we'll have several vocabularies by large
domains:
biological descriptions (generalities) botany zoology Virology Microbiology geography ecology
Just to comment here, one approach being taken by the XHTML working group is to take modular approach with future version of the specification (XHTML 1.1. onwards). This allows defined portions of the spec to be replaced with vendor specific extensions, e.g. replace all the form elements with some extended/amended syntax, or the same with tables, etc.
Such an approach might benefit this effort, in that a core set of descriptive markup for characters can be defined, and then allow additional modular extensions for the differing disciplines.
This has the advantage of providing a small initial spec and data model which can then be extended. (an approach thats worth considering even without modularity included in the final design).
L.