THE POND



Darwin Pond is not like most ponds.  For one thing, it's square.  But don't let that distract you - the swimmers are really where it's at.  The Pond also has a very basic ecology - it consists merely of food bits and swimmers.  Food bits slowly reproduce and spread, while swimmers eat the food, evolve, and make babies for a living.



1) The Garden of Eden

By going to the Pond menu and choosing "Garden of Eden", you can start with a primordial pond of 400 random swimmers and 1000 food bits scattered around near the swimmers.  There are 6 versions of the Garden of Eden, each with different arrangements of swimmers and food.



Mass Extinction

Once in a blue moon, an evolving population will die off, simply on its own, with no warning, or obvious reason.  But there is in fact a reason.  It has to do with luck, chance, and the chaotic dynamics of genetic evolution.  Read up on your Stephen Jay Gould for some in-depth explanations of why species sometimes go extinct for un-obvious reasons.  But don't worry: swimmer populations rarely die out completely - and if things do start to look grim, you can always add some food or some fresh random swimmers to the primordial stew, to help get things rolling again.  



2) Sample Ponds


Darwin Pond comes with six pre-evolved Pond scenarios, each of which demonstrates a particular aspect of swimmer behavior.  These are useful as introductions to Darwin Pond.  



3) The Empty Pond

Also under the Pond menu is a menu called Empty Pond.  This gives you a blank slate: it clears the pond of all swimmers and food and lets you start from scratch.  Think of the empty pond as a painter's canvas - you can add food bits, create new random swimmers, or load up evolved swimmers from previous populations.  



4) Pond Files

You can save the state of the Pond at any time by going to the Pond menu and choosing Save, or Save as....  A standard Windows 95 dialog box appears asking for the name of the pond file you want to save.  Give it a name and select OK.  You can also load up a previously saved file by going to the Pond menu and selecting Open.  



5) The Passage of Time

Time in Darwin Pond is measured in individual clock "ticks".  A tick is equivalent to a frame of animation.  In other words, every time the pond image is visually updated, time advances by one tick.  This can happen many times a second.  



The animation rate of Darwin Pond on your PC may be different than it is on other PC's.  Faster Pentiums will run Darwin Pond faster than slower ones.  Also, you may notice that time runs slower when the swimmer population is at its largest.  This is because there are more calculations the computer must do in order to simulate and display the swimmers.  



Darwin Pond is not synchronized with real time, like the clock on your wall.  Since Darwin Pond uses "simulation time", as opposed to "real time", there is no such thing as a "second", or a "minute" or a "year".  So, swimmer ages are measured in time ticks.  



6) Freezing the Simulation

You will notice something called "Freeze Simulation" in the "Options" menu item.  Selecting this causes time to stop ticking and the swimmers to stop moving.  All physics and behavior are frozen.  Meanwhile, you can still do all the things to swimmers as before, like move them, kill them, zap them, etc.  You can also add and erase food.  To un-freeze the simulation, select the "Freeze Simulation" option again, and all motion will resume as before, along with the changes you made while the swimmers were frozen in time.  



This is a useful feature for those of you who would  like to carefully set up experimental scenarios, and would rather not have swimmers wandering off and mating while you're trying to put them place.  



7) The Color of the Pond

There are four colors you can choose from as a background for swimmers and food.  These colors can be changed by going to the Options menu, and choosing Preferences.  Your four choices are Greenish, Bluish, Brownish, and Grayish.  