LEVIN, RA; LALAND, KN; GRANT, DR; University of Colorado at Boulder; University of St. Andrews; University of Colorado at Boulder: How Do Organisms Respond to Competing Energetic Requirements? The Working Energy/Take-Home Energy Hypothesis

All organisms must obtain energy from their environments, and perform work in order to do so. The working energy/take-home energy hypothesis (Levin and Laland, 2003) explores the relationships and trade-offs between two demands for energy in all living systems. We refer to the energy required and utilized for immediate survival as �working energy,� and the essential energy surplus required for such demands as longer-term survival and reproduction and rearing as �take-home energy.� Organisms are thus hypothesized to be sensitive to changes in the working energy/take-home energy balance, with resulting consequences for the feasibility of strategies that can be utilized by organisms in performing work on their environment. We modeled such trade-offs using a feasibility analysis approach. Our analysis indicates that strategies that conserve working energy will generally be advantageous over strategies that involve increasing the amount of total energy attained from the environment. Moreover, the trade-offs that occur when conservation of working energy has been maximized create direct implications of the working energy/take-home energy hypothesis for energy/information trade-offs in organisms. We explore strategies for the experimental verification of these implications in model physiological, neural, and behavioral systems.