Curated by the new alternative arts consortium Portland Center for the Advancement of Culture, “The Modern Zoo” is an omnibus show featuring dozens of local artists jostling one another in the rambling, one-hundred-thousand-square-foot precincts of a former office building. Loosely organized, if at all, the show combines the enormity of an international art fair with the free-for-all energy of a kindergarten class, spreading its wares through a warren of boardrooms and executive suites like some young-adult version of show-and-tell. Among the hit-and-miss efforts, certain entries stand out for their seriousness and craft. Melody Owen’s Cling, 2003, a collection of hummingbird feeders hung from the ceiling in a double ring formation, casts swirling shadows on the barren walls; Chandra Bocci’s Genesis (Gummy Big Bang), 2003, is an explosion of gummy candies arrayed around a bright yellow-and-orange gummy planet; Paul Green’s painting The Ravaging Flower, 2001, done in the style of high-Renaissance portraiture, shows a melancholy man with a penis growing out of his chest. Coming on the heels of the recent Portland survey “The Best Coast” and alongside the Portland Art Museum’s current biennial, “The Modern Zoo” reflects a regional art scene arriving at some kind of critical mass, communally discovering the intoxicating new emotion called ambition.