lifestyle (noun, pl. lifestyles) – a way of life, an evolutionary adaptation of an entire organism ant all its parts to a particular environment. In the context of human culture the term lifestyle implies a deliberate choice, a "fashion". In the context of organisms and their environments, lifestyle is, however, not a choice. Organisms have acquire adaptations to a particular environment not by choice but because of their evolutionary history. Thus parasitism, as an example of a biological lifestyle, is not a choice but an ecological adaptation. Due to environmental constraints a particular parasite may be force to switch hosts or in the course of evolutionary history may evolve a less antagonistic and more mutual relationship with its host. Radical changes in biological lifestyles are, however, rare and usually require drastic anatomical and morphological changes (these changes often go hand in hand with developmental stages, e. g., a caterpillar may be parasitic on a plant that will later be pollinated by the butterfly).