AbstractThe time and space scales of biological and physical processes governing the patterns of the copepod Calanus finmarchicus are discussed with emphasis on individual-environment and population-environment relationships.A mathematical model of population dynamics coupling the processes at the individual level with the processes driving cohort development permits the construction of a hierarchy of processes and can be used to extract the most important processes and parameterize the others, under various environmental conditions.The outputs of the model are the physiological rates and the individual growth within the stages, as well as the abundances and the bio masses of stages.An example drawn from recent work on the dynamics of Calanus finmarchicus coupled with a physical and biological one-dimensional model in the North Sea is presented. An annual simulation shows three generations of Calanus finmarchicus during the year. The results suggest that growth, development and life strategy are intimately related to the environment