Example Calculations

The first model we'll explore is the geometric model. According to these equations, a population grows uninhibited over time. The important variables in this simulation are the starting population size (N₀) and the rate of increase (r_m). Don't panic. This is not math! The term N₀ simply refers to the population size at time zero (mathematicians and computer science geeks start counting at 0 rather then 1- go figure). The term r_m is just a shorthand term for the rate of increase for the population. This takes into account factors that will increase the population (births and immigration) and those that will decrease the population size (deaths, emigrations, and alien abductions). On the right hand side of the equation N refers to the current population size for a particular generation which is multiplied by the rate of increase. That number is added on to the number found on the left-hand side of the equation We'll work through a few generations starting with N=10 and r_m=0.5