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首页> 外文期刊>Proceedings of the National Academy of Sciences of the United States of America >Historical contingency and the purported uniqueness of evolutionary innovations
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Historical contingency and the purported uniqueness of evolutionary innovations

机译：历史偶然性和进化创新的所谓独特性

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摘要

Many events in the history of life are thought to be singular, that is, without parallels, analogs, or homologs in time and space. These claims imply that history is profoundly contingent in that independent origins of life in the universe will spawn radically different histories. If, however, most innovations arose more than once on Earth, histories would be predictable and replicable at the scale of functional roles and directions of adaptive change. Times of origin of 23 purportedly unique evolutionary innovations are significantly more ancient than the times of first instantiation of 55 innovations that evolved more than once, implying that the early phases of life's history were less replicable than later phases or that the appearance of singularity results from information loss through time. Indirect support for information loss comes from the distribution of sizes of clades in which the same minor, geologically recent innovation has arisen multiple times. For three repeated molluscan innovations, 28-71% of instantiations are represented by clades of five or fewer species. Such small clades would be undetectable in the early history of life. Purportedly unique innovations either arose from the union and integration of previously independent components or belong to classes of functionally similar innovations. Claims of singularity are therefore not well supported by the available evidence. Details of initial conditions, evolutionary pathways, phenotypes, and timing are contingent, but important ecological, functional, and directional aspects of the history of life are replicable and predictable.
机译：生命历史中的许多事件被认为是单一的，即在时间和空间上没有相似之处，类似物或同源物。这些主张暗示着历史在很大程度上取决于在宇宙中生命的独立起源会产生截然不同的历史。但是，如果大多数创新在地球上出现了一次以上，那么历史将在功能角色和适应性变化的方向上是可预测和可复制的。 23个据称独特的进化创新的起源时间远比55个创新的首次实例化的起源远不止一次，后者进化了一次以上，这意味着生命历史的早期阶段不如后期阶段具有可复制性，或者奇异性的出现是由于随着时间的流逝信息丢失。信息丢失的间接支持来自进化枝的大小分布，在进化枝中，相同的，最近的地质学上的创新已经多次出现。对于三个重复的molluscan创新，由五个或更少物种组成的进化枝代表28-71％的实例化。如此小的进化枝在生命的早期历史中是无法发现的。据称，独特的创新源自先前独立组件的结合和集成，或者属于功能相似的创新类别。因此，现有证据不能很好地支持奇异性主张。初始条件，进化途径，表型和时间安排的细节是视情况而定的，但是生命史上重要的生态，功能和方向方面是可复制和可预测的。

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