This is a continuation of Season 3 Episode 12: Double Helix. That episode was engaging, insightful, and enjoyable. Origin of Species, however, was a baseless, hollow shell compared to its prequel.
It seemed as though the writer's got hung up on showing nudity, and didn't think about anything past that. That's probably why the only serious actors (Rifkin and Reynolds) obviously didn't want to be associated with this episode any more than contractually required. The entire episode is as dull and grey as the walls of the set. Poor acting, poor writing, bad direction; it seems like they extended a 30-second ending into an hour-long show.
I really enjoyed The Outer Limits overall, but this episode was awful. If some 13-year-old is tired of looking at the bras in his mom's Sears catalog, he might be entertained by The Origin of Species. Anyone more mature than that certainly won't be.