Evolution of the Nervous System in Relation to Behavior

Abstract

Animals’ nervous systems generate their myriad behaviors. All nervous systems are composed of broadly similar sets of molecular components organized into neurons, neural circuits, and entire nervous systems. These may be diffused nerve nets of hundreds of neurons or highly centralized and cephalized brains containing billions of neurons. Their evolution has been influenced by selective pressures acting on behavior and the energetic costs that they incur. The trade-off between behavioral performance and energy costs affects all aspects of nervous system design, and combined with developmental and phylogenetic considerations, explains the very different anatomies, physiologies, and behavioral outputs of nervous systems.