Survival of the fittest is a phrase which is a shorthand for a concept relating to competition for survival or predominance. It codifies the observance of zoologists and animal breeders that individuals having the highest level of fitness for a particular environment tend to survive longer in it. Moveover, the longer they survive, the more territory they dominate and the more offspring they have -- tending to crowd out competitors. The phrase is essentially a metaphor and is often felt to be unhelpful: it is very close to a tautology, since if "fitness" is measured in the obvious objective terms - survival - the phrase becomes "survival of the survivors".
Gardeners and plant scientists noticed the same thing with hardier varieties of crops, flowers, grass and other plants. Everyone is familiar with the need for weeding a garden or crop field, to prevent the unwanted plants from spoiling the desired harvest.
The concept has also been stretched to cover free market economics. Companies which offer better goods and services survive better in the marketplace and tend to accumulate an ever-growing market share. Poorly-adapting companies will be forced out by better-adapting ones: "killed" by the competition.
The phrase "survival of the fittest" was first used by Herbert Spencer in his 1851 work Social Statics. It was used by Charles Darwin in the 6th edition of The Origin of Species, in a secondary header of Chapter 4 about natural selection [1] and at several places in the text, mostly using the phrase "Natural Selection, or the Survival of the Fittest". He gave full credit to Spencer, writing "I have called this principle, by which each slight variation, if useful, is preserved, by the term natural selection, in order to mark its relation to man's power of selection. But the expression often used by Mr. Herbert Spencer, of the Survival of the Fittest, is more accurate, and is sometimes equally convenient.". At this time the word "fittest" would have primarily meant "most suitable" or "most appropriate" rather than "in the best physical shape". In the first five editions of The Origin of Species, Darwin used the phrase natural selection [2].
In modern times, however, the phrase is widely used in popular literature as a catchphrase for any topic related or analogous to evolution and natural selection. It has thus been applied to principles of unrestrained competition, and it has been used extensively by both proponents and opponents of Social Darwinism.
Many evolutionary biologists criticize how the term is used by non-scientists and the connotations that have grown around the term in pop culture. The phrase also fails to convey the complex nature of natural selection and modern biologists prefer and almost exclusively use the term natural selection in preference.
Two common criticisms
Many opponents of the evolution theory, particularly those who find that it offends their morality or religious precepts argue that 'survival of the fittest' is a justification for violence and cruelty.
Defenders of the idea of survival of the fittest respond to the moral argument in any of several ways. Sometimes they endorse it, at least in part -- indeed, the phrase was invented by Herbert Spencer, who was explicit in applying the notion to human social relations.
But at other times, thinkers who embrace the idea of survival of the fittest draw a sharp dichotomy between what is and what ought to be. They maintain that the biological facts or hypotheses to which they allude have no moral significance whatsoever, and that both anti-darwinians and social darwinians are simply confused.
As to the claim that survival of the fittest is tautology, this, too, has drawn a range of reactions. Some concede that the usage is redundant, but say that it helps to stress the non-teleological nature of survival. Others maintain that fitness refers to a set of qualities that empirically do advance survival, but that can not be known to except in hindsight, by noting which gene lines survive.
