Episode number 2 of Series “Cosmos: a personal voyage”.
Carl Sagan explores the nature of life on earth from its earliest beginnings to the present. The use of computer animation vividly explains evolution and the structure of the cell and DNA, and the real-life example of the Japanese Heike crab whose form has gradually changed through human intervention, demonstrates the process of artificial selection. Although human life is but one branch of the evolutionary tree we are now influencing all other branches. Sagan concludes by speculating on different paths that evolution may take on other worlds with quite different environments.