Chris began by relating today's topics to yesterday's by way of the phosphorus and phytoplankton discussed the previously. Chris then went on to discuss the life cycle. He used his own cat as the main example. He described the cycle of Birth, Growth, Eating, Reproduction, and Death. Next, he moved on to other species of animal and described their cycles as well. This led the students into a population model which the students made with Stella. The model depicted the life cycle of a group of humans, incorporating birth rates and death rates along with several other factors. The students found that if the birth and death rates were the same, then the population stayed the same. Naturally, if one of these factors was larger, then that one got bigger (Example: more people were born & more people died). Chris also explained the idea of delta-time to the students. Using different timesteps and rates, the class obtained several different results from their Stella graphs. Chris explained to the students the various factors that influenced the rate of births and deaths. Some of the factors were war, famine, pestilence, and plague. The factor that really surprised most of the students was the population value itself. The final step was to add in a graph that determines the death rate based on the number of people (which was simply incorporating the aforestated idea).

Next the class went outside to demonstrate the food chain. Some students were phytoplankton, some were different types of fish, some were sharks, and Chris was, of course, GODZILLA--the top of the food chain. The food chain demonstration was an introduction into the model with lynx and hares. The students had to design this model themselves with no assistance.