Abstract
Following the progression on an individual organism as it lives in the ocean naturally leads to a point of view known as a Lagrangian or particle following description. This description records the position of the organism over time and collects information of its status in terms of growth and reproduction. This type of analysis has certain advantages over field descriptions (maps) of populations and their distribution over space and time. Here the Lagrangian description of biology is defined and applied in examples of population dynamics, biogeographic connectivity, and genetics. This involves introduction of the mathematical formulation of Lagrangian analysis and applications to problems such as understanding the results of animal tagging.
