Modularity and emergence: biology’s challenge in understanding life

Abstract

This essay juxtaposes modularity and emergence in the consideration of biological systems at various scalar levels of spatio-temporal organisation. It is noted that reductionism, specialisation and modularity are basic prerequisites for understanding life. It is realised that increased progress of scientific biology in elucidating mechanisms at the level of modular components supports the accusation that the more it advances in materialistic description of details, the more it diverts from understanding the innate properties of life. It is clear that modularity, by taking the whole as the sum of its parts, is insufficient for understanding living systems. At the same time, however, there is emergence, as advocated by Robert Laughlin. Emergence after the integration of modules leads to completely new properties of individual organisms as unique unitary entities, and also of systems of organisms with synergistic and antagonistic interactions of the integrated species. The discussion is predominantly based on examples from plant biology. At hierarchically higher scalar levels emergent biological systems are networks integrating species, biotopes, ecosystems and the entire biosphere of Earth, also named Gaia by James Lovelock, in a natural scientific respect. While investigating modules remains essential, biology as a nature science needs to merge and integrate such information to be able to unfold emergence. Through efforts towards visualising and understanding emergent diversity and complexity, the research discipline of biology will provide invaluable contributions to understanding life, and thus refute the accusation that it diverts from embracing the innate properties of life.

Beyond APs and VPs: evidences of chaos and self-organized criticality in electrical signals in plants

“…19, 2016; Because of the sessile and modular nature and the continuing challenges on their surviving, the plants must be able to perceive, interpret and respond to various environmental stimuli by integrating the signals received by many different sensors in the cells. To this end, they use a system that involves a complex network of signal transduction, involving cell-cell and long distance communication, enabling integration of their body parts (modules) as a whole, providing the ability to adjust their phenotype to different environmental conditions 1,2,3 .…”

Pseudocyclical similarities and structural evolution of modular organisms

“…However, distinguishing the autonomously inte grated units (modules) (Wagner et al, 2007) has proved to be very productive in the analysis of almost any type of system. The ontological and methodolog ical universality of the concept of "module" and "modularity" quickly made them central to modern biology as applied to various structural and organiza tional levels (Kashtan et al, 2009;Lüttge, 2012;Melo and Marroig, 2015). "Modular ideology" is now becoming a priority in evolutionary developmental biology and molecular biology (Xu and Wang, 2010) and in studying network structures of different nature and origin (Clune et al, 2013).…”

Why is it so difficult to identify a single indicator of water stress in plants? A proposal for a multivariate analysis to assess emergent properties

“…However, a new class of models and epistemology have recently called attention to the fundamental properties of complex systems, properties that are generally observed at a larger scale in a system (a top hierarchical level) and that cannot be observed or inferred at smaller scales of observation in the same system (low hierarchical levels). Such properties are broadly referred to as ‘emergent properties’ (Mitchell ; Lüttge ). Within this scientific context, a new class of models that are focused on the analysis of network organisation in complex systems and their dynamic, emergent non‐reductive properties have been proposed (Barabási ; Souza et al .…”

“…; Lucas et al . ; Lüttge ). In addition to the complex interactions among the components of complex networks generating emergent properties, one of the fundamental characteristics of biological organisms is the hierarchical organisation of their subsystems at different levels of the system (Schneider ; Ravasz et al .…”