Journal of Biological Systems · 1994 · 30 citations · 0 references
Life SciencesBiologyEvolutionary BiologyEvolutionary TheoryMicroevolutionNetwork BiologyBiological NetworksDirected Acyclic GraphsEvolutionNetwork DynamicsNetwork ModelingNetwork TheoryConnectivity ThresholdsDigraph RepresentationEpidemic Spreading On NetworksEvolution Of Biological NetworksGraph Theory ConnectivityGraph Theory In BiologyNetwork EvolutionNetwork Topology Evolution
Here I show that digraphs (directed graphs) are inherent both in the relationships between elements of biological systems and in transitions between different system states. Properties of digraphs therefore underlie many biological phenomena, especially criticality and phase changes. Examples include epidemics, development, vegetation change and evolution. An important source of variety in biological systems is the extreme variability in digraph patterns that occurs when levels of connectivity are critical. Many biological processes, including evolution, appear to exploit this variety via a mechanism in which the connectivity of a system flips back and forth across the critical level.