all mutations), that occur during the foetal stage of development. Maurpertuis wrote: "May we not thus explain how, from only two individuals, the multiplication of the most dissimilar species might have followed? They might have owed their first appearance merely to accidental occurrences. Perhaps the elementary parts did not maintain the arrangement which had existed in the animal ancestors: each degree of error could have created a new species, and, thanks to repeated deviations, the infinite diversity of animals manifest today might have resulted. This diversity developed with time, but perhaps grew imperceptibly in the course of the centuries." He wrote in 1750, "Chance has produced a countless number of individuals; a small number of these were constructed in such a way that the parts of the animal could satisfy his needs; in an infinitely greater number, there was neither fitness nor order, and they all disappeared [became extinct]; the only ones which survived were those in which order and fitness prevailed. These species in existence today are only the smallest part of what a blind fate had produced." (Maupertius, Essai de Cosmologie.)Some of Darwin's ideas sound as though they could have been taken line for line from Maupertius writings. Compare this with the Origin, where Darwin wrote: "Natural Selection acts exclusively by the preservation and accumulation of variations, which are beneficial under the organic and inorganic conditions to which each creature is exposed at all periods of life. The ultimate result is that each creature tends to become more and more improved in relation to its conditions. . .If under changing conditions of life organic beings present individual differences in almost every part of their structure . . .then, considering the infinite complexity of the relations of all organic beings to each other and to their conditions of life [environment], causing an infinite diversity in structure, constitution,...
