How do humans influence changes in other species? Has Homo sapiens itself stopped evolving? This program explores natural selection as an ongoing phenomenon, showing how evolutionary processes continue to shape the future of all life on Earth. Exploring the competition for resources, territory, and mates that occurs in any ecosystem, the video illustrates how species differentiation takes place-whether the environment is a petri dish, a jungle, or a major city. Also discussed: morphological, physiological, and behavioral variation; the relationship between agriculture, selective breeding, and genetic modification; and the puzzling anthropological discovery known as the Hobbit.