= Solution
<Plate tectonics> changes the environments in which <natural selection>, <gene flow> and <extinction> operate. \b[It influences both the persistence of habitable conditions and the geographical and chemical opportunities for <evolution>.] It does not prescribe a unique sequence of biological innovations.
Separation of continents by <continental rifting> divides populations and reduces <gene flow>, promoting <allopatric speciation>. <Continental collision> or newly exposed land connections can reunite populations, permit dispersal and introduce competitors or predators. These mechanisms connect <biogeography> to <continental configuration>. Changing the amount and fragmentation of shallow <continental shelf> habitat can also change the opportunities for diversification of marine <organisms>.
Over long intervals, <volcanic outgassing>, <silicate weathering>, carbonate burial and <subduction> exchange <carbon> among the interior, <atmosphere> and <ocean>. In a suitable regime, warmer, wetter conditions increase <silicate weathering>, remove atmospheric <carbon dioxide> and weaken the <greenhouse effect>. This <negative feedback> can support long-lived <habitability>, though it depends on exposed fresh <rock>, available <water> and reaction rates.<A negative feedback mechanism for the long-term stabilization of Earth's surface temperature by James C. G. Walker and others>[Weathering–carbon dioxide–temperature coupling in the proposed long-term stabilization mechanism.]{ref} <Mountain building> changes precipitation, <erosion> and delivery of <nutrients> to the <ocean>, affecting <primary production> and organic <carbon> burial.
The opening and closure of <ocean gateways> changes <ocean circulation>, transport of <heat> and the supply of <oxygen> to deep <water>. Together with movement of land through different latitudes and changes in <sea level>, this reorganizes <climate> and habitat. Enhanced organic <carbon> burial can change atmospheric <oxygen> over long intervals, while a poorly ventilated <ocean> can develop <ocean anoxia>. Such chemical changes alter which forms of <metabolism> are viable.
<Hydrothermal circulation> at <spreading ridges> and through fractured <rock> supplies <chemical disequilibrium> and mineral surfaces. For example, <serpentinization> can produce <hydrogen> usable by <chemolithotrophy> when suitable electron acceptors are available. This supplies a possible setting for <abiogenesis> and early ecosystems; it does not establish that <life> originated there.
There can also be abrupt disruption. Rapid emplacement of a <large igneous province> can change <climate> through gas release; sulfur-bearing <aerosols> can initially cool, whereas sustained <carbon dioxide> release can warm and contribute to <ocean acidification> and <ocean anoxia>. Such perturbations can contribute to <mass extinction>, followed by <adaptive radiation> among survivors. The <Deccan Traps> exemplify the scale of <volcanism> involved, but their association with the <Cretaceous–Palaeogene boundary> does not justify attributing the entire biological crisis to <volcanism> alone. Both gradual environmental reorganization and rare rapid perturbations belong in the explanation.
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