One Voice in the Cosmic Fugue

One Voice in the Cosmic Fugue is the second episode of Cosmos A Personal Voyage. It first aired 5 October 1980 on PBS.

Summary
Carl Sagan discusses the story of the Heike crab and artificial selection of crabs resembling samurai warriors as an opening into a larger discussion of evolution through natural selection and the pitfalls of intelligent design. Among the topics are the development of life on the Cosmic Calendar and the Cambrian explosion; the function of DNA in growth; genetic replication, repairs, and mutation; the common biochemistry of terrestrial organisms; the creation of the molecules of life in the Miller–Urey experiment; and speculation on alien life, such as life in Jupiter's clouds.

Update
In the Cosmos Update ten years later, Sagan remarks on RNA also controlling chemical reactions and reproducing itself and the different roles of comets, potentially carrying organic molecules or causing the Cretaceous-Paleogene extinction event.