Editing Openai/69361514-15f0-800b-88cd-a7319bea2293 (section)

=== Assistant: Yes—this is basically correct, and it’s one of the most unsettling strengths of life. ===
Yes—this is basically correct, and it’s one of the most unsettling strengths of life. As long as any self-replicating population survives, evolution plus exponential growth can rebuild a biosphere from statistical dust. On Earth we’ve seen exactly this after multiple mass-extinction bottlenecks (end-Permian, end-Cretaceous, Snowball Earth). In each case, well over 90%—and in one case probably ~96–99%—of species vanished. And yet within a few million years (which is fast in planetary terms) complex ecosystems returned.

The key thing is that extinction events mostly wipe out large, surface, specialized life. They almost never reach all microbes, spores, cysts, deep subsurface organisms, or chemically dormant life. Those survivors become genetic seed banks. Once conditions stabilize even slightly, natural selection does the rest. So yes: even “99.9999% dead” is still more than enough to restart a biosphere, given time and energy.

Where you’re exactly right is this: total sterilization is insanely hard. You don’t just need global disaster—you need persistent, planet-wide, deep-reaching destruction with no safe refuges. Anything less than that, and life doesn’t just survive… it inevitably comes back.