Leverhulme Centre for Human Evolutionary Studies, Department of Archaeology, University of Cambridge, Cambridge, UK.
Nat Ecol Evol. 2024 Jun;8(6):1180-1190. doi: 10.1038/s41559-024-02390-z. Epub 2024 Apr 17.
The search for drivers of hominin speciation and extinction has tended to focus on the impact of climate change. Far less attention has been paid to the role of interspecific competition. However, research across vertebrates more broadly has shown that both processes are often correlated with species diversity, suggesting an important role for interspecific competition. Here we ask whether hominin speciation and extinction conform to the expected patterns of negative and positive diversity dependence, respectively. We estimate speciation and extinction rates from fossil occurrence data with preservation variability priors in a validated Bayesian framework and test whether these rates are correlated with species diversity. We supplement these analyses with calculations of speciation rate across a phylogeny, again testing whether these are correlated with diversity. Our results are consistent with clade-wide diversity limits that governed speciation in hominins overall but that were not quite reached by the Australopithecus and Paranthropus subclade before its extinction. Extinction was not correlated with species diversity within the Australopithecus and Paranthropus subclade or within hominins overall; this is concordant with climate playing a greater part in hominin extinction than speciation. By contrast, Homo is characterized by positively diversity-dependent speciation and negatively diversity-dependent extinction-both exceedingly rare patterns across all forms of life. The genus Homo expands the set of reported associations between diversity and macroevolution in vertebrates, underscoring that the relationship between diversity and macroevolution is complex. These results indicate an important, previously underappreciated and comparatively unusual role of biotic interactions in Homo macroevolution, and speciation in particular. The unusual and unexpected patterns of diversity dependence in Homo speciation and extinction may be a consequence of repeated Homo range expansions driven by interspecific competition and made possible by recurrent innovations in ecological strategies. Exploring how hominin macroevolution fits into the general vertebrate macroevolutionary landscape has the potential to offer new perspectives on longstanding questions in vertebrate evolution and shed new light on evolutionary processes within our own lineage.
人类物种形成和灭绝的驱动因素的研究往往集中在气候变化的影响上。而种间竞争的作用则关注较少。然而，更广泛的脊椎动物研究表明，这两个过程通常与物种多样性相关，这表明种间竞争起着重要作用。在这里，我们想知道人类物种形成和灭绝是否符合预期的负和正多样性依赖模式。我们使用具有保存变异性先验的化石出现数据，在经过验证的贝叶斯框架中估计物种形成和灭绝速率，并检验这些速率是否与物种多样性相关。我们通过计算整个进化枝中的物种形成率来补充这些分析，并再次检验这些速率是否与多样性相关。我们的结果与控制整个人类进化枝物种形成的总谱系范围多样性限制一致，但在南方古猿和傍人亚科灭绝之前，它们并没有达到这一限制。南方古猿和傍人亚科内部或人类总体内部的灭绝与物种多样性无关；这与气候在人类灭绝中比物种形成中扮演更大的角色是一致的。相比之下，人类的特点是物种形成与多样性正相关，而灭绝与多样性负相关——这是所有生命形式中都极为罕见的模式。人类属突出了多样性与脊椎动物宏观进化之间的关联，强调了多样性与宏观进化之间的关系是复杂的。这些结果表明，生物相互作用在人类宏观进化，特别是物种形成中，起着重要的、以前被低估的和相对不寻常的作用。人类物种形成和灭绝中多样性依赖的不寻常和意外模式可能是种间竞争驱动的人类多次范围扩张的结果，并且由于生态策略的反复创新而成为可能。探索人类的宏观进化如何适应一般的脊椎动物宏观进化景观，有可能为脊椎动物进化中的长期问题提供新的视角，并为我们自身的进化过程提供新的启示。
