This presentation of four theories on the origin of life is designed to promote discussion and lead to research. The theory of “special creation” attributes the origin of life to a supernatural being; the theory of spontaneous generation proposes that life originated from inorganic materials; while the cosmozic theory suggests that life on earth originated elsewhere in the universe. The final theory introduced is the now commonly accepted theory of evolution. Equal emphasis is given to each theory to encourage students to discuss the evidence on which the theories are based.