Description of this stack (further infos in the stack itself)
This HyperCard 2.1 stack (which is freeware) was created as a demonstration of computer simulations in the field of biology. After using it in a practical in June I want to see if other biology students or teachers find it useful or helpful either in understanding so-called ESS models (short for evolutionarily stable strategy, see help text in the stack) or in introducing them to undergraduate students. If you have never heard about ESS models then you will probably want to read an introduction like in a chapter of a book called "An Introduction to Behavioural Ecology" (Krebs, J. R. &Davies, N. B. (eds.). 2nd ed. Blackwell Scientific Publications, Oxford 1987.) before exploring all possibilities of this stack.
Since this stack was planned to be used even by computer beginners I did not include a "Go Home button" but created a "Quit" button instead. For easy use simply put the stack or an alias file into the folder "Startup Items" of System 7 or select it as a startup file in System 6.x. A student then needs only to start the computer and to select “Shut Down” again at the end of the session. Of course there certainly is a way to include even that in the stack (with an Apple Event message). So feel free to add modifications of your own. If you think they should be added to future versions of this stack (well, one never knows...) please let me know, I’d appreciate any suggestions and comments. I can be reached through email (see below).
Known limitations and inconsistencies:
- The variables "Value" and "Damage" should not exceed ten. Otherwise the calculations could end up with negative frequency values which are clearly crap but which are not displayed as such in this version (you just get an unexpected jump in the generation succession). I could have built in a check in the scripts of the buttons, but since they are in the background this limit would also affect other cards like the Jack-Hooknose game where I want to allow for bigger values for the maximum distance.
- For logical reasons it might be clearer for the user to see a new graph being drawn as soon as he clicks on the "Graph" button. Until now, you first get to see a new card where you have to click on another button. My justification is that you may want to see your old graph that was previously drawn in order to compare it with the next one. An additional advantage is that you can return to the "Graph" card later just to see the latest graph (especially useful if you have left that card by accident). An experienced HyperCard user/programmer should have no problem to change this behaviour according to personal taste.
