The Challenger

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Description

Trees once dominated the planet, but grasses eventually challenged their supremacy to become Earth's main form of plant life. In this program, Iain Stewart explains how it happened, and the impact the change had on mammalian evolution. Describing the link between sharp grass blades and the creation of an oxygen-rich atmosphere, Stewart takes viewers on a journey of discovery that includes a look at the Fongoli chimps, who adopt a human-like stance to scan the savanna. And at a Neolithic temple, he explains how one mutant gene in a species of wild grain resulted in the ability to raise wheat and make bread, thus sustaining a workforce that could now build the world's first cities.