#29 · Systems biology

Thresholds and delays determine whether populations persist, coexist or go extinct

The dominant thread is how thresholds and delays govern whether populations persist, coexist or go extinct. The delay differential equation model of polymerase-mediated RNA virus quasispecies analyzes bifurcations, complementation and robustness, including delay-induced extinction (tau-tipping). The minimal temperate phage competition model identifies when prophage-borne defenses invade, coexist cyclically or persist. The hierarchical May-Leonard study addresses selection rules that determine which species combinations persist while others disappear. What is new is the treatment of persistence and extinction as threshold-governed outcomes across these distinct systems, rather than single-system dynamics. The items are heterogeneous, so the shared element is conceptual and methodological rather than a single common mechanism.