.json extensions should be supported for Ajax requests
(consider .xml if more appropriate for cake framework)
GET /users (lists all users)
GET /users/<user_id> (lists the details of a specific user)
GET /species (lists the known species)
GET /species/<species_id> (lists the details of a specific species)
GET /species/<species_id>/occurrences (lists all occurrences of a given a species)
GET /species/<species_id>/occurrences/<occurence_id> (lists the details of a specific occurrence)
N.B. These may change based on PHP Cake conventions