This program illustrates how natural selection works to enable a species to adapt to adverse environments; shows how human breeding of desirable varieties—which antedates by millennia any theories of genetics or evolution—often overrode natural selection; demonstrates how species can be changed by artificial selection and in response to human interference with the environment; and explains the desirability of preserving the gene pool. After viewing the program, students should understand how environmental changes and artificial selection alter the random variability in a population, how breeders strengthen rather than create variation, and why it is so important to preserve the gene pool. (20 minutes)