Natural Selection Simulations

Natural selection is the selection process of individuals with traits best fit for survival in their environment allow them to survive, reproduce, and produce fertile offspring.  Natural selection is the driving force for evolution.  To simulate natural selection, we can use a computer program to simulate natural selection in changing environments and in a different simulation measure both prey and predators over multiple generations.

Part A: Evo Dots

To simulate natural selection, we will use a computer program called EvoDots.  In this program, a population of “Dots,” all the same species has variation by color and movement speeds.  We will measure the effect of natural selection on this population.

  1. Partner with one other student.
  2. Click on the magnify glass in the top right hand corner of the Mac and search for “Evodots.”  Click on the icon.  If it doesn’t open automatically, check the menu bar for a blue, yellow, and red icon that says “EA.”
  3. Click the button that says “new population.”
  4. You will serve as the predator and attempt to “eat” as many of the individuals as possible in 20 seconds.  The individuals show variation beyond just color.  
  5. Click “run” and, using your mouse, eat as many organism (dots) as you can in 20 seconds by clicking on them with the mouse.  Have your partner time you.  Click stop after 20 seconds. No cheating!
  6. Click the small “down arrow” on the right side of the program.  This will expand the window to show a chart.  G is the generation; 1=black, 2=purple, 3=blue, 4=green, 5=yellow, 6=orange, 7=red.
  7. Record how many of each type of the dot species are present in Table 1 after eating: this is the second “Generation 0.”
  8. Record the number of remaining organisms after the first generation from the program in Table 1.
  9. Have the surviving organisms reproduce by clicking “reproduce.”
  10. Click “Run” to begin the next generation and “eat” for another 20 seconds.
  11. Record the number of each color organisms in Table 1 for Generation 1.  This is the starting number of individuals for each color for Generation 1.  The program will have two 0’s, two 1’s, etc.  You want to use the second row as this represent after you have “eaten” or preyed on the organisms.
  12. Repeat steps 5-9 for a total of 3 generations and record your information in Data Table 1.
  13. Trade with your partner and time for them.

  1. What did the experiment show about how prey are selected by predators?

  1. What organism coloration is the best adaptation for the environment (background)? How do you know (use data to prove it)?

  1. What would you expect the populations of the organisms to look like in each environment after 25 generations?

  1. How does the simulation model natural selection?

Table 1.  Number of Individuals per Generation of Dot Species

Generation

Black

Purple

Blue

Green

Yellow

Orange

Red

0

1

2

3

4

Part B: Who Wants to Live a Million Years

To simulate natural selection, the game Who Wants to Live a Million Years pits you as establishing a population of critters who face various environmental changes; the goal is to see the population survive to 1 million years (it’s challenging).  As a “Life Preserver” you can introduce a genetic mutation at any point twice during the game.

  1. Ignoring the mumbling Darwin, select your three variants of the species (all populations have variation).  Describe their variations here (hair, stripes, neck or leg length, etc.)

  1. The population will face environmental changes.  Describe the first change and year it takes place below; if you use a genetic mutation describe it as well.

  1. If the population survives, it will face further environmental changes.  Describe the the second and succeeding changes and year they takes place below; if you use a genetic mutation describe it as well.

  1. What effect did the changing environment have on the population?

  1. What effect did the introduction of genetic mutations have on the population?

  1. How does the simulation model natural selection?