'In the opening pages of The Fantastic: A Structural Approach to a Literary Genre (1973), Todorov evokes the image of a tiger to draw a parallel between changes in the biological and literary “species”:
Being familiar with the species tiger, we can deduce from it the properties of each individual tiger; the birth of a new tiger does not modify the species in its definition. […] The same is not the case in the realm of art or of science. Here evolution operates with an altogether different rhythm: every work modifies the sum of possible works, each new example alters the species. (6)' (Introduction)