Biogeographic dating of speciation times using paleogeographically informed processes

Standard models of molecular evolution cannot estimate absolute speciation times alone, and require external calibrations to do so, such as fossils. Because fossil calibration methods rely on the incomplete fossil record, a great number of nodes in the tree of life cannot be dated precisely. However, many major paleogeographical events are dated, and since biogeographic processes depend on paleogeographical conditions, biogeographic dating may be used as an alternative or complementary method to fossil dating. I demonstrate how a time-stratified biogeographic stochastic process may be used to estimate absolute divergence times by conditioning on dated paleogeographical events. Informed by the current paleogeographical literature, I construct an empirical dispersal graph using 25 areas and 26 epochs for the past 540 Ma of Earth’s history. Simulations indicate biogeographic dating performs well so long as paleogeography imposes constraint on biogeographic character evolution. To gauge whe...传统分子演化模型无法单独估算物种形成的绝对时间，需借助外部校准方可实现，例如化石校准。由于化石校准方法依赖并不完整的化石记录，生命之树中的绝大多数节点都无法被精确定年。不过，学界已对诸多重大古地理事件完成定年；且生物地理过程依赖古地理环境条件，因此生物地理定年可作为化石定年的替代或补充方法。本研究展示了如何以已定年古地理事件为条件，利用时间分层生物地理随机过程估算绝对分化时间。基于当前古地理学研究文献，本研究针对地球过去540 Ma（mega annum，百万年）的历史，以25个区域和26个地质时代构建了经验性扩散图。模拟实验结果表明，只要古地理环境对生物地理性状演化存在约束，生物地理定年便能取得良好效果。为评估……