Investigation 3-1

Simulate Natural Selection with Beetles

  

To get a feel for the process of natural selection, experiment with a population of M&M candy or paper dot “beetles” to test how well each color is adapted to survive on a field of wrapping paper or fabric.

You will need a large piece of colorful patterned wrapping paper, and a large bag of M&M candy to represent beetles. Instead of candy, you may create a population of "dot beetles" by punching holes out of five different colors of paper.

  • First, cover a table with a large piece of colorful patterned wrapping paper. This will simulate the environment.
  • Next count out equal numbers of "beetles" of each color and scatter them across the paper environment. They will represent a population of “beetles” that show variation in the trait of color.
  • Pretend you are a bird predator and collect half the "beetles" by picking them up and setting them aside. Don’t eat the “beetles” yet!
  • Turn your eyes away each time you capture a “beetle” and try not to intentionally favor one color over another. Your actions represent a bird searching for the most visible food in its habitat.
  • Sort the captured "beetles" into piles by color and count them.

1. Which color was the easiest to spot against the colorful background?

2. Which color was best camouflaged?

3. If the surviving camouflaged “beetles” were to reproduce one offspring each, which color of beetle would be most common in the next generation?

4. What do you predict will happen over several generations? How could you test your prediction?

5. What might happen if you altered the environment by using another pattern for the environment or by dimming the lights?

6. Scientists use simulations to test their ideas. What changes would you make in this activity to make it a better simulation of natural selection?



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