Cretaceous fires

In 2010, Bond & Scott proposed that the spread of angiosperms (flowering plants) in the Cretaceous was promoted by the evolution of novel, highly productive (and flammable) plants that generate frequent fires. This was facilitated by the elevated Cretaceous atmospheric oxygen concentration. These novel fire regimes opened spaces and, in turn, further promoted angiosperms—creating a positive feedback that favored angiosperms over gymnosperms (the early angiosperm fire cycle). This is now beautifully explained in a video by PBS Eons!