Some of the Things That Molecules Do

Some of the Things That Molecules Do is the second episode of Cosmos A Spacetime Odyssey. It first aired 16 March 2014 on Fox.

Summary
Neil deGrasse Tyson covers several facets of the origin of life and evolution. He describes both artificial selection via selective breeding, using the example of humankind's domestication of wolves into dogs, and natural selection, that created species like polar bears. Tyson uses the Ship of the Imagination to show how DNA, genes, and mutation work, and how these led to the diversity of species as represented by the Tree of life, including how complex organs such as the eye developed.

Tyson describes extinction of species and the five great extinction events that wiped out numerous species on Earth, while some species, such as the tardigrade, were able to survive and continue life. Tyson speculates on the possibility of life on other planets, such as Saturn's moon, Titan, as well as how abiogenesis may have originated life on Earth. An animation from the original Cosmos shows the evolution of life from a single cell to humankind today.