Evolution of Skittlelicious delicious
The phenotypic alterations of a terrestrial animal can be followed within the context of a classroom simulation activity. The frequency of carapace (covering) colors may vary in response to environmental selection pressures. In this simulation, a predator hunts for Skittlelicious delicious (S.d.) within a given multi-colored environment. After 3 rounds (generations), carapace color frequencies can be compared to the original frequencies to determine the effects of selection pressure on the trait of carapace color.
Procedure:
- Assign the following roles to each member of your team: predator, placer, and recorder.
- Separate the five different color S.d. into five separate cups. Place at least 20 in each cup.
- With the predator turned away from the cloth “environment,” recorder and placer should place 5 of each S.d. on the cloth (be sure to have the characteristic “S” design on the carapace facing down). Be sure to hide the S.d. as effectively as possible.
- At a given signal, the predator turns to face the environment and collects the first S.d. seen. The predator must immediately turn away from the environment, choosing to either eat the S.d. or store in a capture cup.
- The predator proceeds to repeat step 4 until 13 of the 25 total S.d. are collected.
- At this point, the team counts and records the total number of each color remaining.
- To conclude the round (generation), the team doubles the population of S.d. by adding the same amount of given color as remains. For example, if 3 red remain, 3 more red are added to the environment. This reproduction is a vital part of the natural process.
- Members of the team now switch roles and repeat steps 3-7 for two more rounds (generations).
- The exercise can be continued by providing a different cloth environment to the team, followed by a repeat of steps 1-8. This allows the students to assess the effects of background environment on the carapace color frequency ofS.d.
- Student teams should present the data in the form of a histogram (bar graph), with associated text explaining the results in the context of evolutionary language.
Options:
-Provide feeding tools for predator, such as spoons, forks, or knives.
-Alter the feeding tools of the predator over time, simulating the co-evolution of the predator in this predator-prey relationship.
-Have the predator wear goggles with various color filters. Alter these over time (or between groups) to again simulate co-evolutionary responses.
-Have a particular color of S.d. alter orientation by placing them with “S” side up. This behavioral variation can be investigated for predator response.