Of corpses, ghosts and mirages: biomechanical consequences of morphology depend on the environment.

Organisms are subject to the laws of physics, so comparative biomechanics is a powerful approach for identifying basic principles that apply across taxa of how morphology affects performance of mechanical functions such as locomotion, feeding or resisting damage. Journal of Experimental Biology has been a leading journal for decades in publishing studies revealing such basic biomechanical principles. However, field studies of the physical environment, ecological interactions and life-history strategies of organisms reveal which aspects of their biomechanical performance are important to their success in different types of natural habitats, and thus enable us to design ecologically relevant laboratory experiments to understand biomechanical function. Because the fitness consequences of differences in morphology are affected by the biological and physical environment, biomechanics can be used to identify how physical constraints on the performance of organisms with different body plans in variable environments can affect evolution. I illustrate these points with examples from the literature that show how the biomechanical consequences of morphology depend on the ecology of the organisms. Knowledge of the temporal patterns of interactions of organisms with their physical and biological environments is essential for understanding their functional morphology as it changes during ontogeny, and it reveals constraints on their evolution.