“The Broca Divide” is episode five of season one of Stargate SG-1.
Stargate Command has apparently identified Apophis’s stargate destination when he left Chulak. SG-1 and SG-3 go through the stargate and discover a world where some of the inhabitants are primitive primates. When it turns out that that Apophis hadn’t been through, the team return. Soon after, people start transforming into the primates. Only Teal’c and Daniel appear to be immune.
It’s been quite some time since I last saw these episodes of Stargate SG-1 – namely, when they were first released. I only saw the first few seasons, and since then I’ve caught part of one or two seasons (during the Anubis war) quite a few years ago and, more recently, Ark of Truth, Continuum and the entire Stargate Universe and Stargate: Atlantis series. Comparing these episodes to those shows a lot of difference. The newer ones are full of spaceships, space battles, special effects and all-in-all seem a lot more expensive than these early ones which largely consist of the stargate activating as a special effect.