Biologist and Paleontologist Niles Eldredge, originator of the theory of punctuated equilibria and curator of the exhibition Darwin at the American Museum of Natural History, New York, tells about the birth and development of modern evolutionary thought. After exploring writings of early naturalists, he provides his original glimpse on the content of Charles Darwin's private notebooks and manuscripts, following the trail that leads to a modern view of the hierarchical nature of the tree of life. Other scientists and historians comment upon a narrative that leads in a journey across the world, through more than two centuries of creative forces shaping evolutionary theory. The film is divided in three parts, each conceived as a stand-alone film. Part 3/3 is subtitled "Time and space in evolutionary theory: 1935-1970s"