Ana Gasteyer

"Saturday Night Live" is 40 years old this year.

Forty years before its debut — Oct. 11, 1975, during the Ford administration — Jack Benny was in his third year on radio; the Marx Brothers were starring in "A Night at the Opera," their first movie without Zeppo; Bob Hope and Bing Crosby were still five years away from their first "Road" picture; and there was no TV at all.

Forty years on, the world has changed, and changed again. The cast that launched "SNL" — the initials now suffice — are now in their 60s and 70s, and some are no longer of this Earth.

But "Saturday Night Live" itself has proved remarkably durable and...