The Major Transitions of Life from a Network Perspective

Abstract

Many attempts have been made to understand the origin of life and biological complexity both at the experimental and theoretical levels but neither is fully explained. In an influential work, Maynard Smith and Szathmáry (1995) argued that the majority of the increase in complexity is not gradual, but it is associated with a few so-called major transitions along the way of the evolution of life. For each major transition, they identified specific mechanisms that could account for the change in complexity related to information transmission across generations. In this work, I propose that the sudden and unexpected improvement in the functionality of an organism that followed a major transition was enabled by a phase transition in the network structure associated with that function. The increase in complexity following a major transition is therefore directly linked to the emergence of a novel structure–function relation which altered the course of evolution. As a consequence, emergent phenomena arising from these network phase transitions can serve as a common organizing principle for understanding the major transitions. As specific examples, I analyze the emergence of life, the emergence of the genetic apparatus, the rise of the eukaryotic cells, the evolution of movement and mechanosensitivity, and the emergence of consciousness. Finally, I discuss the implications of network associated phase transitions to issues that bear relevance to the history, the immediate present and perhaps the future, of life.

Fractal Structure and Entropy Production within the Central Nervous System

“…The association between network structure and function is by no means new, and has been recently reviewed by Suki, focusing on the emergence of life, genetic function, cells, and consciousness [121]. Suki proposes that phase transitions in structure enable phase transitions in function.…”

Cognition, Information Fields and Hologenomic Entanglement: Evolution in Light and Shadow

“…Furthermore, their evolutionary narrative remains an entirely traditional Darwinian one. Conceptually then, their approach is not specifically different from the Synergism theories of Maynard Smith and Szathmáry in which the object of selection is the synthesis of collaborative components at many levels and at major transitions [ 122 ]. With these theories, the object of selection is shifted by an enlarged pluralistic bandwidth beyond the central genome of a macro-organism but remains centered within selection theory.…”

Are the Somatic Mutation and Tissue Organization Field Theories of Carcinogenesis Incompatible?

“…Rather, they represent the patterns of punctuated evolution, as proposed in the seminal paper by Gould and Eldredge. 43 According to the views expressed by Suki, 42 when the link density in a network increases, whatever the network is or schematically represents, a critical state will inevitably occur beyond which a new property of the network would spontaneously emerge. This property would belong to a higher level of complexity and brings about new functionality.…”

“…SOC is a core mechanism governing spontaneous transition of an organism or biomolecular system towards higher levels of complexity. An excellent discussion of this aspect of SOC may be found in the paper by Suki, 42 in which the author argues that “sudden and unexpected improvement in the functionality of an organism is enabled by a phase transition in the network structure associated with that function.” Major transitions of life include, but are not limited to, emergence of living matter, eukaryotic cells, photosynthesis, sex, multicellularity, vision, consciousness, language, culture, and society. This view of avalanche-like qualitative leaps is somewhat alternative to the vision of evolution as a slow accumulation of beneficial traits through the generations of an organism.…”