The fact that for most known species, reproduction of animal and vegetable life is anisogamous (by the fusion of different gametes) is described by the term dimorphism (or bimorphism). The concept relates to the binary structure of the living world, a structure that is also reflected in many other spheres, such as language. Wherever nature metaphors and analogies are in use, dimorphism is a widespread conceptual and presentational model, even in fields far beyond biology.