Dawn is one in a long line of zombie films by George A. Romero, colloquially known as the Living Dead Series, starting with the classic Night of the Living Dead in 1968. Some of the later movies are, well, not so good, but Dawn is an excellent movie (well, excellent zombie movie).
I'm not going to give the story away here, but as noted in Dawn (and especially the recent Zombieland), there will be survivors, and these survivors will get better at surviving by not being killed, and getting rid of more zombies. As noted in Zombieland;
The first rule of Zombieland: Cardio. When the zombie outbreak first hit, the first to go, for obvious reasons... were the fattiesSo, in my zombie models, I have added a factor to account for the "hardening" of the population, by making the various parameters a function of time. As a reminder, here's the starting point, with all the parameters kept constant.
With the constant values given above, the population crashes.
OK, let's change these. What I've done is use a logistic function to change the values. The key points to this is a time which represents the mid-point of the change, a time scale and a size of change. Here's one where the population stiffens at around 300 days.
Moving the stiffening back again, we should expect the population to do better, and to go back to 200 days, we find
Keep your eyes peeled for the shuffling undead!