The terms adaptation and evolution pre-date Darwin. The term “adapt” comes from the Latin adaptare, to make fit. William Paley used the terms “adapted” and “adaptation” repeatedly in Natural Theology (1809):
“The eyes of fishes also, compared with those of terrestrial animals, exhibit certain distinctions of structure, adapted to their state and elements.”
The word “evolution” stems from the Latin evolutio meaning “unfolding”, particularly “the unrolling and reading of a scroll, the reading of a book”. The term has acquired a general meaning covering any process of formation or growth or development; in biology it was first used as a term to describe embryological development. The word “evolution” was first used in connection with the development of species in 1762 by Swiss naturalist Charles Bonnet, who developed a theory of pre-formation (females carry within them all future generations in a miniature form) and catastrophism.
Curiously, Darwin, in the first edition of The Origin, never used the term “evolution”; instead his preferred phrase for the idea was “descent with modification”. He did use the term “evolved”, however, as the very last word of his text.
The term “natural selection” originates with Darwin, but was criticized as being too anthropomorphic, breathing agency into an inanimate process – selection implies a selector. Darwin in a letter to his geologist friend Lyell, a year or so after completing The Origin, states that if he were starting afresh he would have used the term “natural preservation”.
However, the phrase that caught the public’s imagination, then and now, is survival of the fittest, which originates not with Darwin, but with his contemporary Herbert Spencer. Alfred Russel Wallace regularly urged Darwin to dump the term natural selection and replace it with Spencer’s phrase. Darwin went half way – in the fifth edition of The Origin he added “or Survival of the Fittest” to “Natural Selection” in the title of Chapter 4 and used the phrase several times in the text.
Despite its popularity with the public, the phrase “survival of the fittest” is now seldom if ever used by professional biologists and has been eliminated from any serious presentation of Darwin’s ideas. There are several problems with it. A modern reading misunderstands Darwin’s meaning: in Darwin’s time, the word “fittest” primarily meant “best suited” or “most appropriate” rather than, as now, “in best physical shape”.
But more troublesome, the phrase has helped fuel the excesses of Social Darwinism, erroneously suggesting that evolution provides moral justification for “might makes right” and for the mistreatment and even murder of those designated “unfit”. In addition, if the fittest are defined as those best equipped to survive, the phrase becomes an uninformative tautology that obscures the essential features of natural selection.
Instead, when it comes to the survival of the aptest, “natural selection” has emerged as clear winner!