We present a physics-based framework that runs from fundamental interactions and constants to biospheres, using a sequence of quantitative nonequilibrium thresholds (“gates”). Each gate is an inequality in measurable variables-free-energy flux, reaction-transport rates, replication fidelity, coding capacity, ecological closure, and climate feedback gains. Crucially, the gate vector is anchored in fundamental physics: dimensionless constants (e.g., the fine-structure constant \(\alpha\) and mass ratio \({m}_{e}/{m}_{p}\) ), nuclear resonance placements (e.g., the \({}^{12}\text{C}\) Hoyle state), and statistical mechanics (Landauer’s bound \({k}_{B}T\ln 2\) ) fix the energetic, kinetic, and information-theoretic margins that propagate through the gates. This anchoring lets us propagate sensitivities of the constants into biosphere-level metrics (net primary productivity (NPP), cycle-closure ratios, and climate feedback gain), yielding an end-to-end map from constants to biospheres. The framework is predictive: it yields testable inequalities, margin rankings, and population-level correlations between stellar/planetary boundary conditions/biosphere feasibility. It does not claim point-predictions of life prevalence; rather, it specifies which gate margins are observable-bounded versus prior-dominated under explicitly stated chemistry/solvent families and forward models. Darwinian dynamics (heritable variation under selection) appears mid-pipeline; the end of the pipeline is a planet-scale biosphere capable of sustaining positive NPP and closing elemental cycles over geologic time. Questions of prevalence are secondary; our primary objective was to establish a constructive physics → chemistry → biology → genetics → ecosystems pipeline with testable margins and observables. As a result, we recast abiogenesis and biosphere persistence as a gate vector of falsifiable inequalities and map their margins to exoplanet observables, turning the problem into a phase diagram with explicit, testable slack.
