Looking back at 50 years of “Saturday Night Live”

On October 11, 1975, people tuning into the debut of a late-night comedy show saw something unlike any TV variety extravaganza they’d ever seen. Fifty years later, “Saturday Night Live,” produced almost continuously by Lorne Michaels, is now an entrenched part of pop culture – 90 minutes of live comedy sketches, commercial parodies and musical acts, headlined by a different celebrity host each week. Correspondent Mo Rocca talks with former cast members Rachel Dratch and Fred Armisen, writers Alan Zweibel and Paula Pell, and with Susan Morrison, author of “Lorne: The Man Who Invented Saturday Night Live,” about the creation of a television landmark.