Name That Tune

I was watching Family Guy last night, the episode entitled "'Family Guy' Through The Years." I had the CC on, as is my wont.

During one bit, they parodied the end of the movie Hair, but instead of Berger taking Claude's place in Vietnam, Peter was taking the place of his son, Chris.  In the movie, this is when they play "Let The Sunshine In" (properly known as "The Flesh Failures (Let The Sunshine In).") They used the same tune in Family Guy, except Peter is singing "Let my son die."

Except on the CC, they identified the song as "Aquarius." This is a pretty big difference.  "Aquarius" opens the show and the movie, "Let The Sunshine In" closes it.

I think I understand where the mistake comes from.  The medley "Aquarius/Let The Sunshine In" (also known as "Aquarius/Let The Sunshine In (The Flesh Failures)") was a #1 hit for The 5th Dimension--many think of the songs as being one piece.

But still, two different songs.  Don't even sound anything like each other.