Procedures

globals [population] turtles-own [age is-female] to setup ca crt initial-population ask turtles [ setup-turtle set shape "face happy" ] end to go ask turtles [ move-turtles grow-old reproduce] set population count(turtles) tick end to setup-turtle set age 0 setxy random-xcor random-ycor ifelse (random 100 < 50) [ set is-female true set color pink ] [ set is-female false set color blue ] end to move-turtles right random 360 left random 360 forward 1 end to grow-old set age age + 1 if age > lifespan[die] end to reproduce if (is-female = true and ;; if turtle is female and any? turtles-here with [is-female = false] ;; a male is here and random 100 < birthrate) ;; and encounter is successful [ hatch 1 [setup-turtle] ] end

Information

WHAT IS IT? ----------- This model represents a female and a male reproducing in different conditions. This means that there could be different circumstances in the model, such as the initial-population, lifespan and birthrate. The main focus for this model is to show how many different ways reproduction could happen.

HOW IT WORKS ------------ In this model there are two main agents. One of which is male, this agent moves around randomly searching for a female turtle. The female turtles each have a birthrate chance when it is near a male. When the male and the female come together they would produce another turtle. But when the lifespan of the turtles ends they just die.

HOW TO USE IT ------------- To use this model you first have to click on the "setup" button. This makes the turtles appear on the screen. After this, click on the "go" button, this makes the turtles actually function and move around. For this model there are other things that can be played around with, these include the initial population, birthrate and the lifespan sliders. The "initial population" slider is used to create the amount of turtles that are going to be used to begin with. The "birthrate" slider is used to create the chance of the turtles actually being able to reproduce. The "lifespan" slider is used to create the amount of time that the turtles are going to live. The "population" monitor is used to show the amount of turtles that are present on the screen.

THINGS TO TRY ------------- There are many creative things that could happen with this model. By changing all the sliders to 100, this makes the model become over populated and the screen full with blue and pink happy faces. On the other hand when you put all the sliders to 0, nothing happens because there are no turtles present for anything to happen. The higher the sliders are set the more the turtles are going reproduce because there is no limit to the turtle population.

EXTENDING THE MODEL ------------------- There are also many things that could be extended to this model. One of the things would be that there would be certain turtles that cannot reproduce. This would make the model seem more realistic because many females do not have that ability in the real world. If some turtles did not have this ability then the model would probably be a bit less full.

CREDITS AND REFERENCES ---------------------- Created by Pamela Valdes on March 21, 2008 for the apprenticeship program at Shodor Education Foundation.