Toward a Universal Theoretical Framework to Understand Robustness and Resilience: From Cells to Systems

Research across a range of biological subdisciplines and scales, ranging from molecular to ecosystemic, provides ample evidence that living systems generally exhibit both a degree of resistance to disruption and an ability to recover following disturbance. Not only do mechanisms of robustness and resilience exist across and between systems, but those mechanisms exhibit ubiquitous and scalable commonalities in pattern and function. Mechanisms such as redundancy, plasticity, interconnectivity, and coordination of subunits appear to be crucial internal players in the determination of stability. Similarly, factors external to the system such as the amplitude, frequency, and predictability of disruptors, or the prevalence of key limiting resources, may constrain pathways of response. In the face of a rapidly changing environment, there is a pressing need to develop a common framework for describing, assessing, and predicting robustness and resilience within and across living systems.

An integrated modeling approach to assessing linkages between environment, organism, and phenotypic plasticity

Many of the most interesting questions in organismal biology, especially those involving the functional and adaptive significance of organismal characteristics, intrinsically transcend levels of biological organization. These organismal functions typically involve multiple interacting biological mechanisms. We suggest that subdisciplinary advances have led both to the opportunity and to the necessity to reintegrate knowledge into a new understanding of the whole organism. We present a conceptual framework for a modeling approach that addresses the functioning of organisms in an integrative way, incorporating elements from environments, populations, individuals, and intra-organismal dynamics such as physiology and behavior. To give substance to our conceptual framework, we provide a preliminary focal case study using phenotypic plasticity in the tooth morphology of snails in the genus Lacuna. We use this case study to illustrate ways in which questions about the evolution and ecology of organismal function intrinsically span all organizational levels. In this case, and in many others, quantitative approaches that integrate across mechanisms and scales can suggest new hypotheses about organismal function, and provide new tools to test those hypotheses. Integrative quantitative models also provide roadmaps for the large-scale collaborations among diverse disciplinary specialists that are needed to gain deeper insights into organismal function.