Emergence 2009: Semester Projects I

Emergence

Biology 361 = Computer Science 361
Bryn Mawr College, Spring 2009

 

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Download/view: Evolve04.nlogo

 

WHAT IS IT?
This model is a preliminary stage in my effort to create a basic model of evolution.
HOW TO USE IT
SETUP, STEP, and GO are standard.

ADD PREDATOR adds a single predator at a random location.

INIT-PREDATORS controls how many predators are included in SETUP.

PRED-RADIUS controls the radius in which predators can sense prey.

INIT-PREY controls how many prey are included in SETUP.

SPAWN-AGE controls how many ticks prey must survive for before reproducing.

TRAIT-SETUP controls how the distribution of sight-dist values within the prey population upon SETUP. RANDOM sets each to a random value from 0 to 9, NORMAL sets them randomly based on a normal distribution. SET TO SLIDER sets the value for all turtles to the value set by the INIT-SIGHT-DIST slider.
THINGS TO NOTICE
I used separate breeds for predators and prey so that I could easily control them separately.  I also had to do some careful thinking to get the graph working how I wanted- note the recursion and 'bins' in the graph-trait procedure and the use of the ROUND primitive.
THINGS TO TRY
Try starting out with no predators. Use different TRAIT-SETUP options and different slider settings for the SET TO SLIDER option. Watch how the mean and distribution of trait values varies. Next try adding a predator (or doing a SETUP with some INIT-PREDATORS)- how do predators affect the mean and distribution of trait values? Can you select settings that cause all the prey to go extinct?
EXTENDING THE MODEL
I am intending to incorporate more traits for the prey, starting with limiting their sight to a specific field of vision.  I would also like to add some traits for the predators and see what kind of 'arms race' results.

 

Models created using NetLogo.

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