Answer and Explanation:
The phrase “survival of the fittest” was made famous in the fifth edition of On the Origin of Species by British naturalist Charles Darwin. It suggested that organisms best adjusted to their environment are the most successful in surviving and reproducing1. Darwin borrowed the term from English sociologist and philosopher Herbert Spencer, who first used it in his 1864 book Principles of Biology.
However, Darwin did not consider the process of evolution as the survival of the fittest; he regarded it as survival of the fitter, because the “struggle for existence” is relative and thus not absolute. Instead, the winners with respect to species within ecosystems could become losers with a change of circumstances.
So, while “survival of the fittest” is often associated with evolution, it is important to note that it is not the same thing as evolution. Evolution refers to the cumulative changes in a population or species through time, while “survival of the fittest” is a popular term that refers to the process of natural selection, a mechanism that drives evolutionary change.