1: S
220.00
3 1. Humpback Whales and Sand Lance
2:W
47
j
100.00 of'o-----+-----+-----+------i
0.00
50.00
100.00
Years
150.00
200.00
FIGURE 3.2
and selecting in the graph dialog box both variables that are plotted. Then
click on the arrows to the right of these variables and marks will appear to
indicate setting of upper and lower limits for the plots (Figure 3.3).
The oscillations of our. predator-prey model decrease through time and
ultimately settle down to a steady-state. Run the model for a longer time
frame, say 1000 years, to see what the ultimate steady-state level is. You
can plot the values of each of the two state variables in a numeric displaythe icon to the right of the table on your tool bar (Figure 3.4). Select the numeric display, place it in the STELLA window, double-click on it, select one
of the stocks , specify the Precision as "free float" and check to "Retain Ending Value" and "Show Name." Click on OK, repeat the proce ss for the other
:Itt 7f.:'
..J::::.
1.
2. JijiiiilIII
3.
4.
5.
FIGURE 3.3