Doctor Who/Recap/S7/E02 Doctor Who and the Silurians

Elder Silurian: I have decided that it is possible for the two species to live together on this planet.
Young Silurian: This planet is ours!
Elder Silurian: This other species has developed its own civilisation. We must accept them as equals.
Young Silurian: I disagree! We must destroy them!

The Doctor: Brigadier, at all costs we must avoid a pitched battle.
The Brigadier: You don't still think we can co-exist with the Silurians, do you?

The only Doctor Who story to be officially titled "Doctor Who and..." (legend has it this was due to an error by the production team in putting the prefix onto the onscreen titles). While "Doctor Who" isn't his name, the actor was credited as playing "Doctor Who" until 1981 (and again in 2005), so the Word of God on the subject is clearly a bit suspect.

Anyway, the Brigadier sends for the Doctor and Liz to take a look at an underground laboratory working on a new kind of nuclear reactor. They're getting odd power losses and a bizarrely high level of stress-related illnesses among the staff.

The Doctor investigates and discovers that a neighbouring cave system is the base for a group of intelligent reptilian bipeds which are (inaccurately, as it turns out) named "Silurians" from the geological period from which they date. They have been in hibernation for millions of years, but the power and heat from the new reactor have reactivated them, and they now wish to emerge and reclaim "their" world from the mammals.

The Doctor tries to broker peace and gains the trust of the Silurian leader, but the leader's rebellious son takes power and releases a virus that will destroy humanity. The Doctor and Liz find a cure, but are then told that the Silurians have taken over the underground lab and are going to destroy the Van Allen Belt, bombarding the Earth with radiation deadly to mammals, but not reptiles. The Doctor gets them to retreat back into the caves by overloading the reactor and threatening an explosion. The Brigadier - to the Doctor's disgust - then orders the Silurian base destroyed.

Watch it here

Tropes

Anti-Villain: Everyone aside from The Doctor, Liz and the Elder Silurian.
Arbitrary Skepticism: The Brigadier scoffs at the Doctor when he first tells him that there are intelligent reptilian beings living in the caves. Yeah, as if that's any weirder than robotic yetis, alien cyborgs and living plastic mannequins...
Character Name and the Noun Phrase: The only one, due to an error in the script department.
Downer Ending
Everything's Better with Dinosaurs: The Silurians have a pet Tyrannosaurus or whatever.
Evil Army: Both the Silurians and humans have this trope
Evil Counterpart: The Young Silurian to The Brigadier. Both rebel against more level headed elders vying for peace, both show extreme courage and determination when their respective races are threatened and both are utterly prepared to wipe out the other party to ensure that their people survive. However, this trope is arguably subverted, as neither one is truly more evil than the other, and while the Young Silurian is foiled the Brigadier's orders to have the Silurians wiped out go off without a hitch.
Genocide Dilemma: An unusual mutual example
Grey and Gray Morality: Except for the Doctor and Liz - and perhaps the Elder Silurian - nobody comes out looking particularly good in this story, not even the Brigadier. Most characters on both sides retain sympathetic qualities, however. This sort of complexity - that people in general aren't good or bad - was a staple of Malcolm Hulke's scripts - he was also involved in writing 'The War Games' a story dealing with Deliberate Values Dissonance.
Humans Are the Real Monsters / Aliens Are Bastards
- Humans Are Flawed: It's played on both ends of the spectrum, too - the Silurians are just as xenophobic as their human counterparts, and yet neither side completely looses all sympathy when all their actions are examined in hindsight.
- Then again the Elder Silurian is probably the only thoroughly good character in the story other than Liz and the Doctor.
Kill All Humans: What the more unreasonable Silurians would like to do.
Lizard Folk: The Silurians, with vaguely piscine features.
The Plague: Unleashed on humanity by the Young Silurian in Part 5.
Similar Squad: The Doctor, Liz, and the Brigadier when compared to the Elder Silurian, Silurian Scientist, and Young Silurian respectively.
Shoot the Dog
Third Eye: On the Silurians' heads. It's also a weapon.
Vague Age: Even the Doctor can't get his age straight:

I'm beginning to lose confidence for the first time in my life - and that covers several thousand years.

What the Hell, Hero? - The Brigadier ordering the Silurian compound destroyed at the end, wiping out the colony. After the explosion, the Doctor drives away with a disgusted look on his face.