;last edited by Evan Raskin 6 May 2009 at 11.30a ;work on context ;explain mean value reduction from high starting point (reducing from right-wall effect down to predator radius ;breeds and variables----------------------------------------------------------------------------------- breed[prey] breed[predators predator] globals[trait-list1 ;list of all current sight-dist values trait-list2 gen-list ;list of all current gen values green-diversity ;diversity of sight-dist values blue-diversity sum-so-far sum-so-far2 i ;utility variables ] prey-own[gen sight-dist age group] ;orey variables ;action procedures----------------------------------------------------------------------------------- ;basic go to go ifelse count prey = 0 [user-message "The prey population has gone extinct" stop][ ;if all the prey die, stop ask prey [ifelse any? predators in-cone (sight-dist + 1) 180 [avoid] ;if prey see predators, they run away [set heading random 360 fd 1]] ;otherwise, prey move randomly ask predators [ifelse any? prey in-radius 7 [move-to min-one-of prey [distance myself]] ;if predators smell prey, they jump on them [set heading random 360 fd 2]] ;otherwise, they also move randomly ask prey [if any? predators-here [die]] ;prey die when attacked by predators ask prey [set age age + 1 if age >= 40 [spawn die]] ;prey spawn and die when they reach spawning age if count prey > 0 [update] tick] end ;prey avoid predators to avoid face min-one-of (predators in-cone (sight-dist + 1) 180) [distance myself] ;prey face the closest predator in their sight range rt 180 ;then turn around jump 5 ;then jump forward end ;prey produce offspring to spawn hatch ((count prey / 500) ^ -.755) ;prey hatch a number of offspring based on prey density [set age 0 set sight-dist random-normal sight-dist .5 ;hatchling setup... set gen gen + 1 if sight-dist > 9 or sight-dist < 0 [die]] ;left wall & right wall effects end ;graphing and maintenance procedures----------------------------------------------------------------------------------- ;update umbrella procedure to update set i 0 graph-distribution ;updates trait distribution plots set i 0 set sum-so-far 0 set sum-so-far2 0 calc-diversity graph-diversity ;calculates and plots trait diversity update-lists ;updates trait value lists graph-values ;updates trait values plot end ;calculates Simpson's Index of diversity to calc-diversity if any? prey with [color = green][ set sum-so-far sum-so-far + (((count prey with [color = green and round sight-dist = i]) / count prey with [color = green]) ^ 2)] if any? prey with [color = blue][ set sum-so-far2 sum-so-far2 + (((count prey with [color = blue and round sight-dist = i]) / count prey with [color = blue]) ^ 2)] set i i + 1 ifelse i < 10 [calc-diversity] [ if any? prey with [color = green][set green-diversity (1 - sum-so-far)] if any? prey with [color = blue][set blue-diversity (1 - sum-so-far2)]] end ;updates diversity plot to graph-diversity set-current-plot "trait diversity" if any? prey with [color = green] [set-current-plot-pen "green" plot green-diversity] if any? prey with [color = blue] [set-current-plot-pen "blue" plot blue-diversity] end ;updates trait distributions plots to graph-distribution if count prey > 0 [ set-current-plot "trait value distribution" if i = 0 [clear-plot] plotxy i ((count prey with [(round sight-dist) = i])/ (count prey) * 100) set i i + 1 if i < 10 [graph-distribution]] end ;updates trait values plot to graph-values set-current-plot "mean trait values" set-current-plot-pen "Green" if any? prey with [color = green] [plot (mean trait-list1)] set-current-plot-pen "Blue" if any? prey with [color = blue][plot (mean trait-list2)] end ;keeps updated lists of trait values for determination of means to update-lists set trait-list1 [] set trait-list2 [] set gen-list [] ask prey [ifelse color = green [set trait-list1 lput sight-dist trait-list1] [set trait-list2 lput sight-dist trait-list2]] ask prey [set gen-list lput gen gen-list] end ;setup procedures----------------------------------------------------------------------------------- ;runs setup when the model is opened to startup setup end ;basic setup to setup ca create-prey 200 ;create prey ask prey [set color black set age random 40 set xcor random-pxcor set ycor random-pycor set gen 1] ;setup prey... setup-traits create-predators initial-number-predators ;create predators ask predators [set xcor random-pxcor set ycor random-pycor set shape "target" set color red] ;setup predators update end ;sets up different initial distributions of trait values to setup-traits ask prey [if trait-value-distribution = "random" [set sight-dist random 10 set color green] ;setup random distribution of sight-dist values if trait-value-distribution = "set to slider" [set sight-dist green-trait-value set color green] ;set sight-dist values to group1-dist if trait-value-distribution = "set to sliders" [ifelse who < (count prey / 2) ;give prey sight-dist values group1-dist and group2-dist, 50:50... [set sight-dist green-trait-value set color green] [set sight-dist blue-trait-value set color blue]]] ask prey [if sight-dist > 9 or sight-dist < 0 [die]] ;left & right wall effects end ;adds a predator to add-pred create-predators 1 [set shape "target" set color red set xcor random-pxcor set ycor random-pycor] end @#$#@#$#@ GRAPHICS-WINDOW 200 10 650 481 16 16 13.33333333333334 1 10 1 1 1 0 1 1 1 -16 16 -16 16 0 0 1 ticks CC-WINDOW 5 708 659 803 Command Center 0 PLOT 7 220 191 370 Trait Value Distribution Trait Value % of Population 0.0 10.0 0.0 100.0 false false PENS "Dist" 1.0 1 -16777216 true BUTTON 7 10 99 43 Setup setup NIL 1 T OBSERVER NIL U NIL NIL MONITOR 49 649 141 694 Mean (Green) mean trait-list1 3 1 11 MONITOR 7 370 99 415 # Prey (Green) count prey with [color = green] 0 1 11 BUTTON 7 187 99 220 Step go NIL 1 T OBSERVER NIL S NIL NIL BUTTON 99 187 191 220 Go go T 1 T OBSERVER NIL G NIL NIL SLIDER 7 43 191 76 initial-number-predators initial-number-predators 0 5 1 1 1 NIL HORIZONTAL SLIDER 7 121 191 154 green-trait-value green-trait-value 0 9 8 1 1 NIL HORIZONTAL CHOOSER 7 76 191 121 trait-value-distribution trait-value-distribution "random" "set to slider" "set to sliders" 0 BUTTON 99 10 191 43 Add Predator add-pred NIL 1 T OBSERVER NIL P NIL NIL MONITOR 99 414 191 459 # Predators count predators 0 1 11 MONITOR 324 649 416 694 Diversity (Green) green-diversity 3 1 11 PLOT 324 493 588 649 Trait Diversity Time Diversity 0.0 10.0 0.0 1.0 true true PENS "Green" 1.0 0 -10899396 true "Blue" 1.0 0 -13345367 true SLIDER 7 154 191 187 blue-trait-value blue-trait-value 0 9 1 1 1 NIL HORIZONTAL PLOT 49 493 313 649 Mean Trait Values Time Mean Trait Value 0.0 9.0 0.0 9.0 true true PENS "Green" 1.0 0 -10899396 true "Blue" 1.0 0 -13345367 true MONITOR 7 414 99 459 Prey Generation mean gen-list 0 1 11 MONITOR 221 649 313 694 Mean (Blue) mean (trait-list2) 3 1 11 MONITOR 496 649 588 694 Diversity (Blue) blue-diversity 3 1 11 MONITOR 99 370 191 415 # Prey (Blue) count prey with [color = blue] 0 1 11 @#$#@#$#@ WHAT IS IT? ----------- This model demonstrates the evolutionary effects of selection pressure. HOW TO USE IT ------------- SETUP, STEP, and GO are standard. ADD PREDATOR adds a single predator at a random location. INITIAL-NUMBER-PREDATORS controls how many predators are included in SETUP. TRAIT-VALUE-DISTRIBUTION controls the initial distribution of trait values within the prey population upon SETUP. RANDOM sets each to a random value from 0 to 9, SET TO SLIDER sets the value for all prey to the value set by the GREEN-TRAIT-VALUE slider. SET TO SLIDERS sets the value for half of the prey to the value set by GREEN-TRAIT-VALUE and sets the value for the other half to BLUE-TRAIT-VALUE (the second half also become blue). The PREY-GENERATION monitor reports the average generation of prey. The MEAN monitors report the average trait value for each prey population (which is also shown in the MEAN TRAIT VALUES plot). The distribution of trait values is shown in the TRAIT VALUE DISTRIBUTION plot. The TRAIT DIVERSITY plot and monitors keep track of the diversity of trait values in the prey populations, calculated using Simpson's Diversity Index. A value of zero indicates that all prey (of that color) have the same trait value; a value of one indicates that trait values are exactly evenly distributed in the population. THINGS TO TRY ------------- Start out with no predators. This will show the same trends as in the Non-Selective version. Now add a predator (or predators)- how do predators affect the mean and distribution of trait values? How do they affect diversity? This demonstrates selection. Prey with higher trait values are more likely to survive long enough to reproduce. This creates a shift in the trait value distribution toward the higher end of the range and increases the mean value. It also creates a slight drop in diversity, as a disproportionate number of prey have high trait values. Try again with more predators. Does selection happen faster? Using the TRAIT-VALUE-DISTRIBUTION chooser, set up two populations with different initial trait values. Is one favored? Do they evolve at the same rate? Note that mean trait values never stabilize all the way at the maximum value, as you might expect. This is due to the right-wall effect (some offspring of prey with a trait value of 9 will die, as they will have trait values of more than nine, so turtles with a trait value of 9 will not be as strongly favored as they might otherwise be. As an extension of the model, you might try removing the right wall (or putting in on a switch) to see how high selection will push the mean trait value. HOW IT WORKS ------------ Each turtle has a variable that stores its trait value. Turtles get older with every tick, and when they have lived for forty ticks, they reproduce, making turtles with trait values distributed normally around their own trait value. They die after reproducing, and the number of offspring they produce is based on the number of living turtles, which keeps the population stable. Any turtle that is given a trait value outside the range from 0 to 9 (which happens when a turtle with a trait value of 0 or 9 reproduces) dies, producing the left- and right-wall effects. At each tick, turtles look ahead for predators. If there is a predator within a half-circle with a radius of the turtle's trait value, the turtle will turn around and move away from the predator. Otherwise, the turtle mill move randomly. THUS, PREY WITH HIGHER TRAIT VALUES ARE MORE LIKELY TO SEE AND AVOID PREDATORS, and hence more likely to survive long enough to reproduce. At each step, predators smell around themselves within a radius of 7. If there are any prey within this range, the predator jumps on whichever is closest and kills it; otherwise, it also moves randomly. @#$#@#$#@ default true 0 Polygon -7500403 true true 150 5 40 250 150 205 260 250 airplane true 0 Polygon -7500403 true true 150 0 135 15 120 60 120 105 15 165 15 195 120 180 135 240 105 270 120 285 150 270 180 285 210 270 165 240 180 180 285 195 285 165 180 105 180 60 165 15 arrow true 0 Polygon -7500403 true true 150 0 0 150 105 150 105 293 195 293 195 150 300 150 box false 0 Polygon -7500403 true true 150 285 285 225 285 75 150 135 Polygon -7500403 true true 150 135 15 75 150 15 285 75 Polygon -7500403 true true 15 75 15 225 150 285 150 135 Line -16777216 false 150 285 150 135 Line -16777216 false 150 135 15 75 Line -16777216 false 150 135 285 75 bug true 0 Circle -7500403 true true 96 182 108 Circle -7500403 true true 110 127 80 Circle -7500403 true true 110 75 80 Line -7500403 true 150 100 80 30 Line -7500403 true 150 100 220 30 butterfly true 0 Polygon -7500403 true true 150 165 209 199 225 225 225 255 195 270 165 255 150 240 Polygon -7500403 true true 150 165 89 198 75 225 75 255 105 270 135 255 150 240 Polygon -7500403 true true 139 148 100 105 55 90 25 90 10 105 10 135 25 180 40 195 85 194 139 163 Polygon -7500403 true true 162 150 200 105 245 90 275 90 290 105 290 135 275 180 260 195 215 195 162 165 Polygon -16777216 true false 150 255 135 225 120 150 135 120 150 105 165 120 180 150 165 225 Circle -16777216 true false 135 90 30 Line -16777216 false 150 105 195 60 Line -16777216 false 150 105 105 60 car false 0 Polygon -7500403 true true 300 180 279 164 261 144 240 135 226 132 213 106 203 84 185 63 159 50 135 50 75 60 0 150 0 165 0 225 300 225 300 180 Circle -16777216 true false 180 180 90 Circle -16777216 true false 30 180 90 Polygon -16777216 true false 162 80 132 78 134 135 209 135 194 105 189 96 180 89 Circle -7500403 true true 47 195 58 Circle -7500403 true true 195 195 58 circle false 0 Circle -7500403 true true 0 0 300 circle 2 false 0 Circle -7500403 true true 0 0 300 Circle -16777216 true false 30 30 240 cow false 0 Polygon -7500403 true true 200 193 197 249 179 249 177 196 166 187 140 189 93 191 78 179 72 211 49 209 48 181 37 149 25 120 25 89 45 72 103 84 179 75 198 76 252 64 272 81 293 103 285 121 255 121 242 118 224 167 Polygon -7500403 true true 73 210 86 251 62 249 48 208 Polygon -7500403 true true 25 114 16 195 9 204 23 213 25 200 39 123 cylinder false 0 Circle -7500403 true true 0 0 300 dot false 0 Circle -7500403 true true 90 90 120 face happy false 0 Circle -7500403 true true 8 8 285 Circle -16777216 true false 60 75 60 Circle -16777216 true false 180 75 60 Polygon -16777216 true false 150 255 90 239 62 213 47 191 67 179 90 203 109 218 150 225 192 218 210 203 227 181 251 194 236 217 212 240 face neutral false 0 Circle -7500403 true true 8 7 285 Circle -16777216 true false 60 75 60 Circle -16777216 true false 180 75 60 Rectangle -16777216 true false 60 195 240 225 face sad false 0 Circle -7500403 true true 8 8 285 Circle -16777216 true false 60 75 60 Circle -16777216 true false 180 75 60 Polygon -16777216 true false 150 168 90 184 62 210 47 232 67 244 90 220 109 205 150 198 192 205 210 220 227 242 251 229 236 206 212 183 fish false 0 Polygon -1 true false 44 131 21 87 15 86 0 120 15 150 0 180 13 214 20 212 45 166 Polygon -1 true false 135 195 119 235 95 218 76 210 46 204 60 165 Polygon -1 true false 75 45 83 77 71 103 86 114 166 78 135 60 Polygon -7500403 true true 30 136 151 77 226 81 280 119 292 146 292 160 287 170 270 195 195 210 151 212 30 166 Circle -16777216 true false 215 106 30 flag false 0 Rectangle -7500403 true true 60 15 75 300 Polygon -7500403 true true 90 150 270 90 90 30 Line -7500403 true 75 135 90 135 Line -7500403 true 75 45 90 45 flower false 0 Polygon -10899396 true false 135 120 165 165 180 210 180 240 150 300 165 300 195 240 195 195 165 135 Circle -7500403 true true 85 132 38 Circle -7500403 true true 130 147 38 Circle -7500403 true true 192 85 38 Circle -7500403 true true 85 40 38 Circle -7500403 true true 177 40 38 Circle -7500403 true true 177 132 38 Circle -7500403 true true 70 85 38 Circle -7500403 true true 130 25 38 Circle -7500403 true true 96 51 108 Circle -16777216 true false 113 68 74 Polygon -10899396 true false 189 233 219 188 249 173 279 188 234 218 Polygon -10899396 true false 180 255 150 210 105 210 75 240 135 240 house false 0 Rectangle -7500403 true true 45 120 255 285 Rectangle -16777216 true false 120 210 180 285 Polygon -7500403 true true 15 120 150 15 285 120 Line -16777216 false 30 120 270 120 leaf false 0 Polygon -7500403 true true 150 210 135 195 120 210 60 210 30 195 60 180 60 165 15 135 30 120 15 105 40 104 45 90 60 90 90 105 105 120 120 120 105 60 120 60 135 30 150 15 165 30 180 60 195 60 180 120 195 120 210 105 240 90 255 90 263 104 285 105 270 120 285 135 240 165 240 180 270 195 240 210 180 210 165 195 Polygon -7500403 true true 135 195 135 240 120 255 105 255 105 285 135 285 165 240 165 195 line true 0 Line -7500403 true 150 0 150 300 line half true 0 Line -7500403 true 150 0 150 150 pentagon false 0 Polygon -7500403 true true 150 15 15 120 60 285 240 285 285 120 person false 0 Circle -7500403 true true 110 5 80 Polygon -7500403 true true 105 90 120 195 90 285 105 300 135 300 150 225 165 300 195 300 210 285 180 195 195 90 Rectangle -7500403 true true 127 79 172 94 Polygon -7500403 true true 195 90 240 150 225 180 165 105 Polygon -7500403 true true 105 90 60 150 75 180 135 105 plant false 0 Rectangle -7500403 true true 135 90 165 300 Polygon -7500403 true true 135 255 90 210 45 195 75 255 135 285 Polygon -7500403 true true 165 255 210 210 255 195 225 255 165 285 Polygon -7500403 true true 135 180 90 135 45 120 75 180 135 210 Polygon -7500403 true true 165 180 165 210 225 180 255 120 210 135 Polygon -7500403 true true 135 105 90 60 45 45 75 105 135 135 Polygon -7500403 true true 165 105 165 135 225 105 255 45 210 60 Polygon -7500403 true true 135 90 120 45 150 15 180 45 165 90 square false 0 Rectangle -7500403 true true 30 30 270 270 square 2 false 0 Rectangle -7500403 true true 30 30 270 270 Rectangle -16777216 true false 60 60 240 240 star false 0 Polygon -7500403 true true 151 1 185 108 298 108 207 175 242 282 151 216 59 282 94 175 3 108 116 108 target false 0 Circle -7500403 true true 0 0 300 Circle -16777216 true false 30 30 240 Circle -7500403 true true 60 60 180 Circle -16777216 true false 90 90 120 Circle -7500403 true true 120 120 60 tree false 0 Circle -7500403 true true 118 3 94 Rectangle -6459832 true false 120 195 180 300 Circle -7500403 true true 65 21 108 Circle -7500403 true true 116 41 127 Circle -7500403 true true 45 90 120 Circle -7500403 true true 104 74 152 triangle false 0 Polygon -7500403 true true 150 30 15 255 285 255 triangle 2 false 0 Polygon -7500403 true true 150 30 15 255 285 255 Polygon -16777216 true false 151 99 225 223 75 224 truck false 0 Rectangle -7500403 true true 4 45 195 187 Polygon -7500403 true true 296 193 296 150 259 134 244 104 208 104 207 194 Rectangle -1 true false 195 60 195 105 Polygon -16777216 true false 238 112 252 141 219 141 218 112 Circle -16777216 true false 234 174 42 Rectangle -7500403 true true 181 185 214 194 Circle -16777216 true false 144 174 42 Circle -16777216 true false 24 174 42 Circle -7500403 false true 24 174 42 Circle -7500403 false true 144 174 42 Circle -7500403 false true 234 174 42 turtle true 0 Polygon -10899396 true false 215 204 240 233 246 254 228 266 215 252 193 210 Polygon -10899396 true false 195 90 225 75 245 75 260 89 269 108 261 124 240 105 225 105 210 105 Polygon -10899396 true false 105 90 75 75 55 75 40 89 31 108 39 124 60 105 75 105 90 105 Polygon -10899396 true false 132 85 134 64 107 51 108 17 150 2 192 18 192 52 169 65 172 87 Polygon -10899396 true false 85 204 60 233 54 254 72 266 85 252 107 210 Polygon -7500403 true true 119 75 179 75 209 101 224 135 220 225 175 261 128 261 81 224 74 135 88 99 wheel false 0 Circle -7500403 true true 3 3 294 Circle -16777216 true false 30 30 240 Line -7500403 true 150 285 150 15 Line -7500403 true 15 150 285 150 Circle -7500403 true true 120 120 60 Line -7500403 true 216 40 79 269 Line -7500403 true 40 84 269 221 Line -7500403 true 40 216 269 79 Line -7500403 true 84 40 221 269 x false 0 Polygon -7500403 true true 270 75 225 30 30 225 75 270 Polygon -7500403 true true 30 75 75 30 270 225 225 270 @#$#@#$#@ NetLogo 4.0.4 @#$#@#$#@ @#$#@#$#@ @#$#@#$#@ setup wiggle mean values @#$#@#$#@ @#$#@#$#@ default 0.0 -0.2 0 0.0 1.0 0.0 1 1.0 0.0 0.2 0 0.0 1.0 link direction true 0 Line -7500403 true 150 150 90 180 Line -7500403 true 150 150 210 180 @#$#@#$#@