Watch a professor explain the evolutionary war that gave us caffeine

Few of us think much about how our kitchens came to be full of so many thrilling tastes and aromas, like the warmth of cinnamon or the punchy bite of pepper. But when Noah Whiteman opens a cabinet, he sees not just ingredients for a tasty snack but the products of a four-billion-year-long coevolutionary war between plants and animals.

“It has led to things like caffeine, to things like aspirin,” says Whiteman, a professor of Integrative Biology and Molecular and Cell Biology. “People like me ask, ‘why would the coffee plant make caffeine?’” 

As Whiteman explains in this episode of the UC Berkeley video series 101 in 101, that’s partially because some plants, like coffee, have developed caffeine at least in part as a poisonous defense against chewing insects and other enemies. As it turns out, what harms insects and their tiny bodies gives many of us larger humans a brisk chemical jolt to start the day. Many plant species make poisons that are lethal to insects, but some insects in turn have coevolved with these plants to even take advantage of the poisons. 

Whiteman is perhaps best known for his work leveraging CRISPR gene editing to decipher how the monarch butterfly can ingest, tolerate and store the heart poisons of the milkweed plant in levels that make their bodies toxic to predatory birds. But he has also explored coevolutionary poisons that might be more familiar to anyone with a medicine or spice cabinet in his 2023 book “Most Delicious Poison.”

“Coevolution has shaped most of life on earth; whether it’s the evolution of our immune system, whether it’s the evolution of color vision, whether it’s the evolution of the monarch butterfly to resist the poisons of the milkweed plant,” says Whiteman. Watch the video, part of a series that challenges UC Berkeley experts to distill the basics of their field or work in only 101 seconds, to learn why Whiteman believes UC Berkeley is uniquely positioned to explore the intertwined ways that species have coevolved in fascinating ways. 

Watch more 101 in 101 videos featuring UC Berkeley faculty and experts here.