The game advances. I just added basic breeding, Oh baby!
Population increases based on your self fertility rates, and how busy everyone is. Of course, there's no way to assign jobs right now, so everyone is available to help breed, how fortunate!
Busy people still count, but only for half.
For giggles I started up a village of gryphons and let them do as they wanted.
They went out to the ruins and gathered up food, and fucked a lot, resulting in a rapid population boom.
The food wasn't coming in as fast as new mouths, and the population crashed as a dozen people die off and morale plummets(no effect yet).
As time goes on, population and food does lots of crazy dances until population slams down to 2 people, and remains stable there while the two loyal gryphons forage, slowly amassing a tiny store of goods, then they have a baby, yay!!
With three, the population begins to grow faster, and the bouncing resumes until the entire village dies out some 15 turns later.