Towards a Research Programme Aiming at Causes and Consequences of Reticulate Evolution

Evolution is reticulate. Reticulation increases diversity and complexity on the different levels of the evolutionary hierarchy. In addition to the tendency for diversity and complexity to increase in unchecked evolutionary systems by ongoing divergence (‘Zero-Force Evolutionary Law’, ‘Biology’s First Law’), reticulate evolution, therefore, acts as a second mechanism for the establishment of evolutionary novelty and the rise in biodiversity and biocomplexity (‘Biology’s Second Law’). This provides the raw material for subsequent diversity-confining drift and selection processes. In order to fully appreciate reticulation processes as part of an updated paradigm of evolutionary biology, a research programme on the topic should encompass the identification of the fundamental evolutionary entities as vertices and the study of the relationships among these vertices as edges in the resulting network architectures. Additionally, along with surveys on the underlying determinants, this will lead to the study of emergent boundary conditions for reticulations and for the porosity of evolutionary entities. Finally, the programme should address the question whether there are equilibrium conditions between the complete fusion and complete isolation of evolutionary entities (‘Goldilocks Zones’) that foster reticulate evolution. As tools in this research programme, machine learning and modelling approaches, along with methods in the field of network reconstruction, transcriptomics, epigenetics, and karyology, are identified.