Your First Generation
When your first generation of turtles is displayed,
you may notice that overall the figures are not that
impressive. This is, of course, to be expected, since
the turtles are created in a completely random fashion.
In fact, if any of the turtles show any signs of
interesting behavior, this is merely a low probability
event and should be considered a blessing.
However, do not be discouraged. As you begin to
selectively choose turtles for reproduction and
evolution, you will see dramatic jumps in the level
of sophistication of your turtles. For each new
generation of turtles does not have to re-learn the
complexities of their parents, they are fortunate enough
to inherit them from the genetic constituency of their
parents. In fact, as new figures appear in succeeding
generations, you will begin to notice the parts that
they inherited from their parents, and even begin to
identify different turtles as being siblings!
Once you have evaluated the figures of your first
generation of turtles, you will certainly wish to
evolve a new generation of turtles to see the
evolutionary process in full swing. But first, you
must decide which turtles will be fortunate enough
to participate in the reproduction of this new
generation of more elite figure drawing turtles.
Turtle Fitness Selection
Before evolving a new generation of turtles, it is
beneficial to select only the turtles you are interested
in pursuing. If you allow all of the turtles to evolve
equally, then the population tends to converge genetically.
When this happens, one or several turtles will begin to have
fitness values much higher than all of the other turtles.
These super turtles will slowly begin to dominate your
population and squeeze out any new turtles. Thus, you should
select those that you wish to pursue and those that you do not.
This allows you to focus in on particular traits in the turtles,
and to pursue these traits in successive generations.
You may change the fitness of a turtle for reproduction by
using a shift-left-click. Left-clicking on a turtle's figure
while holding down the shift key will cause the turtle's
fitness to be toggled. Thus, if the turtle was originally
fit (indicated by a blue border) it will be made unfit and
will not be selected for reproduction (indicated by a red
border). Accordingly, if the turtle was originally, it would
be marked as fit again.
In technical terms, when a turtle is fit, its fitness value
is determined by certain qualities of the image that is drawn,
such as how many lines it draws, how many colors are used, and
how many turns are made. When a turtle is marked as unfit, the
fitness value is simply set to zero, which means the turtle is
almost never selected for reproduction.
Population Evolution
Once you have chosen the turtles that are fit to be reproduced,
you can evolve your next generation of turtles. To accomplish
this task, select the Evolve Population item in the File menu.
This command will clear the population window's display, evolve
the next generation of turtles, and begin displaying their
figures in their respective squares. Again, the amount of time
needed to perform this drawing depends upon the complexity of
each turtle's algorithm, the number of turtles in the population,
and the speed of your computer.