I have to write a Critical analysis of TV genres, I have chosen Science fiction.!

I have to write a Critical analysis of TV genres, I have chosen Science fiction.?

It asks for my analysis to take into account both textual and contextual features, I have to include close reference to at least two seperate series from my genre of choice. I have chosen Star Trek and Doctor Who, it does not give specific reference to which series I should do, but I thought the sixties origanal series from each would probably be better.
The problem I am having is which episodes I should choose, is there anyone that knows some relevent episodes that I could work with and their release dates please?
For textual it means that I have to include narrative, genre, theme and visual style. For contextual I have to include conditions of production, critical and popular reception, and the wider social and cultural circumstances. So any help with relevent episodes that I could use would be fantastic, thanks in advance :-) Natasha.

5 days ago
As much as I would love to do the origanal Star Trek v next generation, I cannot :-(

Some of the more "important" episodes:
Plato's Stepchildren featured one of the 1st interracial kisses on TV. The kiss is "forced" on the show due to censorship.
The City on the Edge of Forever won a Hugo and Writer's Guild Award.