EnVO/GO/ecocore/PCO

[diatomsRcool]

Add to the readMe, information about how terms are divided between EnVO, GO, ecocore, and PCO. In response to @cmungall comment on #19

[ramonawalls]

PCO (population and community ontology) is the oldest and was originally scoped to cover collections of organisms, their process, and their qualities. Processes, however, should be in GO. Qualities of collections of organisms (e.g., diversity, richness) are in PCO, and I am comfortable keeping them there, but some people may expect them in ECOCORE. What about collections of organisms that pertain to particular domains, like social entities or families? For these, I have so far followed ENVO's practice of including them until some more specific ontology arrises to which I can cede them.

BCO (biocollections ontology) was started to provide a place to harmonize concepts from Darwin Core and MIxS and to generally describe "occurences" which can be either material samples or observations. We eventually adopted OBI's terms for specimen and planned process, but observation is still much more general and does not belong in BCO. BCO is currently a mixed bag of terms describing biodiversity collections and general terms used for modeling biodiversity data. I think moving some upper level BCO terms to COB will help solve this problem.
TODO for Ramona: Make a PR to COB for observing process.

ECOCORE (ontology of core ecological concepts) was the last one to be developed. Because ECOCORE did not exist for a long time, many ecological concepts were already in PCO and BCO. Because biodiversity collections and populations and communities overlap with ecology so much, it is difficult to determine which of these ontologies should be the home for many terms. The results is that some issues get passed back and forth on github trackers, and in the end, people don't know where to file tickets. We keep talking about the need to write a paper to clarify scope, but no one has time. Maybe we can agree on how to divide things up here.

Transferred here from OBOFoundry/OBOFoundry.github.io#1542

[ramonawalls]

@cmungall I have tried my best to add this as a card to https://github.com/orgs/OBOFoundry/projects/7, but no luck. Can you add it?