Survival of the fittest
Spencer's Principles of Biology was the first to use the phrase survival of the fittest in print. Darwin agreed that the phrase survival of the fittest was better than natural selection. Natural selection personified nature, but was really about survival. Survival of the fittest would avoid this problem, but it "lost the analogy between nature's selection and the fanciers" (breeders). The phrase was first used by Darwin in the 5th edition of The Origin published in 1869, in which Chapter 4 describes "Natural Selection, or the Survival of the Fittest".