Environment fluctuations as well as random fluctuations within a biological organism take part of its life or evolution. The quoted ''organism'' maybe a cell, a multicellular organ, an individual, a population or a set of populations, etc. It is possible to understand many general aspects of these fluctuations' influence on the life or evolution of these organisms through simplified models, in particular dynamic equations like that of Langevin.
fluctuations and dissipation; biological evolution