The most fundamental unit of traditional biodiversity - the individual organism (defined as a physically connected, multi-cellular aggregation, with all of the cells clonally derived from one ancestral cell) - has no parallel in the world of prokaryotic biology. Yet recent advances (metagenomics tools, etc) have shown that about half of the world's biomass and by far most of its physiological (as opposed to morphological, or mechanical) biodiversity occurs in the prokaryotic realm. Other work is establishing that symbiosis (in the sense of the bio-outsourcing of some key biological functions) is far more common than traditionally recognized. In fact, because horizontal gene transfer (HGT) occurs without regard for species boundaries, it is now becoming clear that some microbial genes are in fact more like attributes of a particular ecosystem than than they are of a particular individual or species. These ecosystem-specific genes are found in many different species in the same ecosystem and they are not found in the same species in different ecosystems. (This is why, for example, the same "cassette" of pathology genes is often found spreading across multiple bacterial species in hospital settings.)

All of the above suggests that an understanding of biodiversity is incomplete, and significantly so, without the inclusion of microbial biodiversity, both as a component of ecosystems ("free living" microbial communities) and also at the level of full understanding of macroscale organisms (as influenced by the presence, make-up, physiology, and function of their associated microbiomes).

From the perspective of biodiversity informatics, the complete addition of a microbial component using current methods and schemas is not possible. This session will begin with an overview of the gaps in today’s biodiversity information systems which preclude an accurate understanding of patterns of life on Earth, and how those patterns are changing. This overview will be followed by a discussion around possible roles for Darwin Core in helping to fill these gaps, and how the standard might have to evolve in order to fulfill these roles.