Sixty-six million years ago, a meteorite struck the Earth with enough force that the ensuing environmental changes, including floods, earthquakes, variable temperatures and light-obscuring dust clouds, possibly wiped out dinosaurs and other pre-historic life. Scientists believe this opened a path for mammals, and ultimately humans, to evolve. A new study by Dana Royer, associate professor of earth and environmental sciences, and colleagues from the University of Arizona and the Denver Museum of Nature and Science suggests that the chaos in the wake of the space rock's impact changed the Earth's plant life as well. Deciduous plants survived and flourished to a…