12/17/2014 02:54 EST | Updated 02/16/2015 05:59 EST

The Simpsons celebrates 25 years of laughs

For a quarter of a century, The Simpsons has taught us catchphrases such as "Doh!" and "Okily dokily," and has made people laugh until they cried. 

The first episode of the animated series aired 25 years ago today, on December 17, 1989.

"The fact that [The Simpsons] has survived all the transitions that television has undergone … has given it that permanence, but they really knew what they were doing," UBC professor Toph Marshall told The Early Edition's Rick Cluff.

"I get to call everything that I watch and consume research," said Marshall, whose primary research focuses on ancient Greek literature and how it relates to society.

Marshall said The Simpsons has made an indelible mark on contemporary culture.

"One of the things I notice about my students is that many of them can recognize scenes from classic films. They haven't seen the classic films, but they have seen The Simpsons parody."

Marshall said when The Simpsons first went to air, it created opportunities for jokes and social commentary that other shows at the time weren't providing.

"I think the representation of mainstream religion in America hasn't been more honest and frank," he said.

Marshall said while many longtime fans will contest his assertion the show is as good today as it was 25 years ago, he said the sitcom has maintained the quality of the original episodes.

"It is as good. It's consistent. They're always doing new things," he said.

To hear the full interview with Toph Marshall on The Early Edition, click the audio labelled: The Simpsons turns 25.