Passage:
While the 'RNA World' hypothesis has long dominated abiogenesis research by proposing that self-replicating RNA molecules preceded metabolic networks, recent biochemical modeling has reignited interest in 'metabolism-first' paradigms. Proponents of hydrothermal vent models, such as Wächtershäuser's iron-sulfur world hypothesis, argue that surface-bound prebiotic chemistry in alkaline vents provided the requisite thermodynamic drive for early organic synthesis without initial genetic catalysis.
Scholars favoring this metabolic primacy view assert that RNA's structural instability under primordial ocean conditions renders the RNA-first scenario chemically implausible. However, their insistence that metabolic cycles could achieve self-sustaining complexity in the complete absence of genetic memory oversimplifies the problem of biological fidelity. Without an informational template, auto-catalytic chemical networks inevitably decay into non-specific tar-like polymers—a fatal constraint that metabolism-first advocates have consistently glossed over.
Conversely, synthetic biologists advocating the 'ribozyme-first' model have recently demonstrated prebiotic pathways for ribonucleotide synthesis under plausible geochemical conditions. Yet, their experimental setups often rely on pure, high-concentration reagents rarely found in natural Hadean environments, representing an overengineered laboratory idealism rather than a realistic prebiotic mechanism.
Ultimately, neither pure genetic primacy nor unguided metabolic self-organization offers a fully coherent account of life's origin. The most promising conceptual shift lies in 'co-evolutionary' models, which suggest that primitive peptides and nucleic acids co-emerged within mineral matrices. Though still structurally embryonic and lacking comprehensive empirical validation, this unified framework avoids the dogmatic reductionism of its predecessors and offers a far more plausible geochemical trajectory.
Question:
Match each hypothesis or claim discussed in the passage with the author's precise stance or tone toward it.
- Wächtershäuser's iron-sulfur world (metabolism-first) hypothesisSkeptical due to a fatal oversight regarding informational fidelity, despite acknowledging its thermodynamic basis
- The ribozyme-first (RNA World) modelCritical of its reliance on overengineered lab idealism, despite acknowledging recent synthetic demonstrations
- The co-evolutionary model of peptides and nucleic acidsGuardedly optimistic regarding its conceptual promise, despite recognizing its present lack of empirical proof
- The claim that RNA structural instability makes RNA-first models chemically implausibleImplicitly approving of its core chemical rationale regarding primordial environmental constraints