Names: ______Date: ______
Variation in Beadbug Populations
Objective: To understand the requirement of variation within a population for evolution by natural selection to occur.
Introduction: In the land of prints and patterns live the Beadbugs. Beadbugs are small ordinary creatures who eat and breed in various kinds of meadows that closely resemble brightly colored fabrics. One characteristic of this species is that it has adapted to these wild and bright habitats by existing in various colored variants. These are white, pink, yellow, orange, light blue, teal, black, brown and dark blue. This is important to ensure survival. Some colors of Beadbugs thrive in some environments but do rather poorly in others.
The biology of Beadbugs is quite interesting. They live in groups of 48 individuals; each group can be all one color, or of mixed colors. They eat brightly colored flowers or candy. They reproduce slowly, producing only one offspring in each generation.
Their primary predator is a bird, the Beadbug Boogie. It zooms over meadows, keeping a sharp eye out for Beadbugs. It catches ONE PREY AT A TIME, taking it back to its nest to feed its young. Each day, each Boogie captures 24 Beadbugs for its young. At the end of each day the Beadbugs left on the meadow reproduce one offspring per individual (= one generation).
Procedure:
A. Setting up Beadbug/Beadbug Boogie Scenarios
1. One member of each team will act as the Beadbug Boogie, capturing and taking back Baedbugs to the nest one-by-one.
2. A second member of the group will tally the counts and “reproduce” and distribute the Beadbugs on the meadow
· It is important that the Boogie looks away from the meadow each time it takes a Beadbug back to its nest. Also, the best way to “survey” the meadow is to stand right over it.
B. Scenario 1
1. A group of 48 Beadbugs begins the season with 16 of each 3 different colored variants. These variants live together on a “meadow” (fabric).
2. Every day for twelve days Boogie takes 24 Beadbugs and every day the remaining Beadbugs produces one offspring.
3. Record and GRAPH the numbers of each color variant of Beadbug remaining after each of 12 generations.
Meadow (fabric) Type: ______
1
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Answer the following questions:
1. Did any of the variants disappear from the meadow? Why or why not (explain in terms of variation within the population)?
2. Which is the most common variant at the end of the 12 generations of predation? Predict what would happen to this variant if placed in another meadow that had a contrasting appearance.
C. Scenario 2 – repeat steps for Scenario 1 but with a new fabric and new color variants
Meadow (fabric) Type: ______
Generation / Color: / Color: / Color:1
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D. True and False
Based on the two data sets just completed, determine which statements below are True or False.
1. There are different patterns of survival for the Beadbug variants depending on which meadow they inhabit ______
2. Considering both meadows together, no color variant will die out due to predation by the Beadbug Boogies ______
3. Variation of color does not influence “FITNESS” in Beadbugs ______
4. The dominant color variant is different in each meadow because fitness varies according to how well populations adapt to the environment ______
E. Scenario 3 – repeat steps for Scenario 1 & 2 but with a new fabric and new color variants
Meadow (fabric) Type: ______
Generation / Color: / Color: / Color:1
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On the reverse side of this page graph your results for at least one scenario. You may enter the data into Microsoft Excel to produce your graph.
DO NOT forget to label your axis and give your graph an appropriate title!!