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Bowhead whales (Balaena mysticetus), denizens of Arctic seas, are known to live more than 200 years, yet they show few signs of the age-related ailments that plague other animals, including humans. Even the bowhead's closest cetacean relative, the much smaller minke whale, lives only 50 years. That suggests the larger whales (which have more than 1000 times as many cells as humans) have evolved some special natural mechanisms that protect them against cancer and aging.

For years whale evolution was characterized by speculation and limited evidence. Evolution critics even focused on whales as a means to criticize evolutionary theory. Now whale evolution represents one of the best examples of "macroevolution." This "clicker case" uses this fascinating story of historical irony as a backdrop to the study of whale evolution. First, students study an array of whale fossils to learn how evolution is properly viewed as a branching, relationship-based process, not a linear, progressive, "chain-of-being." Using this view they learn how scientists seek to reconstruct past relationships and study transitional features, not search for "missing links." Students then learn that evidence for macroevolution relies on several lines of independent evidence from fossils, comparative anatomy, embryology, genetics, and paleoecology. With a focus on macroevolution, this case makes a critical contribution to evolution education. It could work well in a lower level undergraduate biology / evolution / paleontology course (non-majors or majors), or in an upper-level evolution course, perhaps early in the semester as a primer for related topics.