“The world, the earth's surface, is practically full, that is to say, fully occupied. Only one pair of young can grow up to take the place of the pair--male and female--which have launched a dozen, or it may be as many as a hundred thousand, young individuals on the world.... The ‘struggle for existence’ of Darwin is the struggle amongst all the superabundant young of a given species, in a given area, to gain the necessary food, to escape voracious enemies, and gain protection from excesses of heat, cold, moisture, and dryness. One pair in the new generation--only one pair--survive for every parental pair. Animal population does not increase: ‘Increase and multiply’ has never been said by Nature to her lower creatures. Locally, and from time to time, owing to exceptional changes, a species may multiply here and decrease there; but it is important to realise that the ‘struggle for existence’ in Nature--that is to say, among the animals and plants of this earth untouched by man--is a desperate one, however tranquil and peaceful the battlefield may appear to us. The struggle for existence takes place, not as a clever French writer glibly informs his readers, between different species, but between individuals of the same species, brothers and sisters and cousins.... In Nature's struggle for existence, death, immediate obliteration, is the fate of the vanquished, whilst the only reward to the victors--few, very few, but rare and beautiful in the fitness which has carried them to victory--is the permission to reproduce their kind--to carry on by heredity to another generation the specific qualities by which they triumphed. “It is not generally realised how severe is the pressure and competition in Nature--not between different species, but between the immature population of one and the same species, precisely because they are of the same species and have exactly the same needs.... A distinctive quality in the beauty of natural productions (in which man delights) is due to the unobtrusive yet tremendous slaughter of the unfit which is incessantly going on and the absolute restriction of the privilege of parentage to the happy few who attain to the standard described as ‘the fittest.’”