Pocket Mouse-Fitness

1 collaborator

lin xiang (Author)

MODEL IDEAS

This module provides students with opportunities to explore/test the impact of different components of natural selection. Students may also explore the concept of fitness in this model.

HOW IT WORKS

A population of mice will be generated when you start the model. Before pressing on the "start" button, you may adjust the "color-variation" slider to decrease or increase the mouse color variation of the starting population. The "color-variation" slider also determines the possible range of progeny coloration. Use the "environment-color" slider to adjust the environment color to be lighter or darker.
Every mouse carries 20 units of energy. They randomly move in the environment and loses 1 unit of energy per move. If the environment patch color is not black (0), it gains an amount of energy determined by the "energy-gained" slider. If the net of the energy of a mouse is 0, it dies. The carrying capacity of the habitat ranges from 500 to 600.
If a mouse cumulates 40 units of energy, it reproduces one offspring. If the "color-heritable?" switch is on, the offspring inherits the parent color or mutate to any color ranging from 31 (dark brown) to 38.5 (light brown) based on the chance determined by the color-variation slider. If the color-heritable? is off, the offspring can be any color ranging from 31 (dark brown) to 38.5 (light brown).
Due to the predation, the more similar is the mouse color to the environment color, the more likely the mouse survives. The "Number-of-visual-predators" slider allows you to adjust the intensity of the predation. When selection pressure is 0, there is no predation
Users may input the number of years to control the years to run the simulation. It is particularly useful for testing ideas systematically.

HOW TO USE IT

When assigning tasks to students, we suggest you define the controlled variable value so students can get the desired results. One set of option is:

color-heritable? ON Color-variation 15 Energy-gained 1.5 Number-of-visual-predators 15 Environment-color 37 Years 1000

Then students may change one of the variables to explore its effect on the population.
Students may label any of two mice in the simulation to compare their fitness in a certain environment (a certain background color).

CREDITS AND REFERENCES

This module is made by Dr. Lin Xiang at Weber State University. If you mention this model in a publication, we ask that you include the citations below.

Xiang, L. (2019). Pocket Mouse Module-Fitness. Department of STEM Education, University of Kentucky, Lexington, KY.

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Click to Run Model

breed [mice mouse]
turtles-own [energy labeled order]

globals [x y   ;mouse position
         order-number    ;track labled mice order
         name-1  name-2 name-string
         watched]

to-report time-period
  report ticks / 40
end 

to setup
  clear-all
  setup-mice
  setup-patches
  reset-ticks
end 

to setup-mice
  create-mice Starting-Population-Size
  ask mice [
    set color 31 + random-float (Color-variation / 2)
    set shape "mouse side"
    set size 1.25
    setxy random-xcor random-ycor
    set labeled 0
    set order 0
    set energy 20]

    set order-number 0
end 

to setup-patches
  ask patches [set pcolor Environment-color]
end 

to go
  if years = 0 [user-message "Number of years is needed" stop]
  if ticks > years * 40 [stop]

  if color-heritable? = false [ask mice [set color 31 + random-float 7.5]]
  diff-survival
  move
  forage
  dead
  reproduce
  regrow
  if count mice = 0 [user-message "All mice have died."  Stop]
  tick
end 

to move
  ask mice [rt (random 180)
               fd 1
               set energy energy - 1]
end 

to dead
  ask mice [if energy <= 0 [die]]
end 

to forage
  ask mice [if pcolor = Environment-color [set energy (energy + Energy-gained) set pcolor pcolor - 0.75]]
end 

to reproduce
  ask mice [
    if energy >= 40
    [hatch 1
      [set energy 20
       if random 100 < Color-variation [set color ((color - 1) + random-float 2)]
        if color < 31 [set color 31]
        if color > 38.5 [set color 38.5]]
      set energy energy - 20
      ] ]
end 

to regrow
  ask patches with [pcolor != Environment-color] [set pcolor Environment-color]
end 

to diff-survival
    ask mice [
      if random 2500 < (abs (color - Environment-color) * Number-of-visual-predators * 0.3) [die]
    ]
end 

to pick-mice

  if count mice with [labeled = 1] >= 2 [user-message "Two mice have been labeled. Unlabel the mice first." stop]
  if any? mice = false [user-message "No mice here." stop]


  if mouse-inside? [
    if mouse-down? [
      let test-mouse min-one-of mice [distancexy mouse-xcor mouse-ycor]
      if test-mouse != nobody [
        ask test-mouse [if count mice with [labeled = 1] = 0 and label = "" [set label "A" set labeled 1]      ;label the 1st selected moues as "A"
                        if count mice with [labeled = 1] = 1 and label = "" [set label "B" set labeled 1]      ;label the 1st selected moues as "B"
        ]
  ]]]



  if count mice with [labeled = 1] >= 2 [stop]   ;disable the button when two mice are labelled.
end

There are 6 versions of this model.

Uploaded by	When	Description	Download
lin xiang	about 5 years ago	minor adjustment	Download this version
lin xiang	about 5 years ago	Watch and unwatch	Download this version
lin xiang	about 5 years ago	watch a mouse	Download this version
lin xiang	about 5 years ago	Add population control	Download this version
lin xiang	over 5 years ago	Fit in NetLogo web Window	Download this version
lin xiang	over 5 years ago	Initial upload	Download this version

Attached files

File	Type	Description	Last updated
Pocket Mouse-Fitness.png	preview	Preview for 'Pocket Mouse-Fitness'	over 5 years ago, by lin xiang	Download

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