The biology students got to explore speciation by using skittles! They were given the information that a species of beetles comes in a variety of colors (yellow, orange, red, purple, and green). These beetles are living together on a small island. They then observed what happens to the beetles as environmental pressures act on the population.
Round one was to remove the beetles from the cup and spread them out on the paper towel. The paper towel represented an island. They recorded how many beetles they had of each color under Initial Population in a data table and calculated the percentage of each color.
The students were then told that a storm brought flood waters to the island carved out a river separating the population into two groups. With a pen, they had to randomly draw a line separating their skittles into two groups to represent the river that the beetles can no longer cross. Next, they recorded how many beetles were in each population and reflected on the isolation that occurred.
Round two asked the students to reflect on the type of isolation that occurs when one population of the beetles chooses a mate who sings a loud mating song and then one who sings a quiet song if the two populations were to be mixed.
Round 3 asked the students to predict which color beetle would thrive best on sandy terrain and grassy terrain. Then, the students were told they were predators and had to spot the beetles that are not able to camouflage. In group one, they ate three of each color (if available) except the green beetles. In group two, they ate three of each color (if available) except the yellow beetles. This round was finished by recording the populations again in the data table.
To finish the lab, the students were asked if the beetles in groups one and two came into contact in 100 years would reproduce with each other or become separate species.
The many rounds of this lab really allowed the students to analyze different scenarios that occur in speciation. It tested their critical thinking skills and mathematical calculations. For their reward upon completion, they got to eat the skittles!
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