Endpoints assessed at the population or community level are most often the result of the sum of effects on individuals, arising from the effects at the cellular and molecular levels. Within this framework, these lower biological level endpoints are more responsive at an early stage of exposure, making them potential toolboxes to be used as early-warning markers to address stress. Given this, by linking responses and understanding organisms' metabolism and physiology, the possibilities for the use of biomarkers in stress biology are vast. Here, biomarker comprehensive examples are given to enlighten the need to link levels of biological organization, and their usefulness for a myriad of fields and applications is presented and discussed.
Keywords: cost of tolerance; ecotoxicology; energetics; integrated biomarker response; mechanisms of action; neurotoxicity; oxidative stress.