In an Idiots first, the guys take on a three part episode, covering a very breviated history of wolves becoming dogs, then how different breeds came about, going into breeds that have gone extinct over the years or were rolled into other breeds, and then concluding with a discussion about bringing one breed, the French Bulldog, away from the brink of extinction.
Part 1 is the discussion of wolves, specifically a breed of wolf that no longer is on this planet, most likely because it assimilated quietly into modern dogs. They talk of how dogs spread throughout the world, the cause of them joining human ranks, why a symbiotic relationship was so important it came to what we have today, and discuss other things, like ring evolution (editors note, Cory talks about birds on Darwin Island and erroneously refers to them as wrens, but they were actually finches) and selective breeding for working needs.