Fig. 5. Animated time series simulating colonization of a 10 x 10-degree grid by a hypothetical invasive species, as modeled using a reaction-diffusion process. A population of 100 individuals is introduced at the centre of the grid, and logistic population increase, coupled with diffusion, occurs until the population reaches carrying capacity. The number in the upper left corner indicates the iteration number. The colors correspond to the values of individual cells along a gradient from red through blue and green to yellow and back to red; cells are reshaded at each iteration.