Biological inhabitants are defined by their state and transition functions. The state is the set of characteristics that define the individual. Transitions functions change the state of the individual based on its observed behavior.
All ecosystem members include their position as part of their state. Position is defined by two (or three) integers representing their geographical location in the ecosystem's grid. To provide movement, there is a transition function, move(), that randomly selects the direction of the move and the next time the individual will move.
The direction is one of the eight cells adjacent to the individual's current cell, select by a uniform random variable. To move again, the individual must decide when it will move. This time is used to post a future event that will cause another change in the location of the individual.
When a move transition is made in our lyme disease model, the mice must also transition ticks. The mouse object selects a number of ticks to fall off and sends this information to the cell. In turn, the cell selects a set of ticks that infest the mouse.
This example summarizes our current approach to environment-individual interactions. The individual decides what to leave in the cell based on observed probability distribution and the cell decides what to give the individual based on observed distribution.
We have not yet addressed the problem of fauna in our simulation.
The demonstration below couples the physical model with the biological model.