"Survival of the fittest" is a phrase which is shorthand for a concept relating to competition for survival or predominance. Originally applied by Herbert Spencer in his Principles of Biology of 1864, Spencer drew parallels to his ideas of economics with Charles Darwin's theory of evolution by what Darwin termed natural selection.
Darwin first used Spencer's phrase "survival of the fittest" as a synonym for "natural selection" in the fifth edition of On the Origin of Species, published in 1869. It is a metaphor, not a scientific description, and is both incomplete and misleading. Survival is only one component of selection, and for example where a number of males survive to reproductive age, but only a few ever mate, the difference in reproductive success stems mainly from ability to attract mates rather than ability to survive. In an evolutionary sense, fitness is the average reproductive output of a class of gene
at 3:42 PM on Mar. 3, 2009