I love creative science analogies, which is why I'm digging this story about a lecture given by Bob Paul, a biology professor at St. Mary's College of Maryland. Paul attempts to explain some of the basic concepts of evolutionary theory using candy. For instance, the Mars-made Snickers bar and the Nestle-made OhHenry! bar can be thought of as examples of convergent evolution—unrelated species developing similar traits in response to similar environmental pressures. Some of his examples get a little too convoluted, but this one—an explanation of how two groups of the same species can turn into two different species—is delightful.
Paul also discussed one of Darwin's major discoveries on his way to publishing The Origin of Species. After noticing 13 finch species on the Galápagos Islands (west of Ecuador in the Pacific Ocean) and the different environments on each of the islands, Darwin proposed that an ancestral finch species, spread over all of the islands, began to diverge into several new species.
This occurred as each ancestral population developed distinctly different traits on each island to adapt to the selection pressures over evolutionary time.
Paul used this phenomenon (known as allopatric speciation) to explain the evolution of Hershey Kisses and Snow Caps, both with a similar shape but the latter with a sugar-covered top.
Beginning as one population of Hershey Kisses in an open plain with a mountain range, the candies were separated after a major environmental change caused the advancement of a glacier southwards that met with the mountain range, separating the population of Hershey Kisses across an impassable line of mountain and ice.
As the northernmost population began to adapt to cooler temperatures by selecting for a trait for "fur" (the sugar coating), the southernmost population maintained their furless structure.
Once the glacier receded, allowing both populations to intermingle again, they were two different species unable to successfully reproduce with one another.
Submitterated by candycritic