Flower power


At the first Divinity School Wednesday lunch of the academic year, the Field Museum's William C. Burger wowed this week's crowd with heroic tales of flowers. Yes, said the animated, white-bearded curator emeritus in the Field's Department of Botany, flowering plants have changed the world. Without nice-looking and -smelling flowers, insects wouldn't be attracted to and pollinate them, creating the extremely diverse set of plants that make up, say, rainforests.

Even primate evolution wouldn't have occurred the same way without flowering plants. Primates, originally insectivores, climbed trees to eat the bugs gathered near the fruits and flowers, developing long limbs to reach their prey. Over time, as primates began eating fruits, bending wrists and fingers evolved to examine the food, and the monkeys' eyes moved to the front of their heads for better three-dimensional vision as they jumped the trees. The resulting flatter face meant monekys couldn't see behind them to ward off predators, so they lived in small groups and looked after each other.

Another unsuspecting flowering plant, grass, brought primates out of the forest. First appearing 25 million years ago in South America, grasslands expanded as Earth dried and cooled. Eventually, Burger said, summarizing millions of years in a sentence, "one of the apes got up on its hind feet and moved to the savannah," where herbivores grazed. Here primates found beef. Eating meat literally beefed up mother's milk with proteins and nutrients that helped infant brains grow bigger. So grasslands, he said, "allowed us to become who we are."

Ending on a not-so-high note from his book—Flowers: How They Changed the World (Promethius Books, 2006)—Burger warned of hazards to flowers and the rest of the earth. "There are 6 billion people on the planet, and no one's talking about pulling the brakes," he said. Such overpopulation, he writes, strains water resources, agricultural soil, urban environments, and declining fisheries; and more than half the human population is malnourished. "Clearly, human beings are not living in sustainable harmony with the biosphere that supports them."


Photos: Burger in Swift Hall (top); An amateur photographer, Burger shot this beetle visiting a wild geranium (courtesy Prometheus Books).

September 28, 2006