The impact of Quaternary Ice Ages on mammalian evolution
The impact of Quaternary Ice Ages on mammalian evolution
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DOI：
10.1098/rstb.2003.1436
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发表时间：
2004-02-29
影响因子：
6.3
通讯作者：
Lister, AM
中科院分区：
文献类型：
--
作者：
Lister, AM
第四纪是哺乳动物广泛进化的时期。大多数现存物种都是在这个时期出现的，其中许多物种表现出对特殊的第四纪环境的适应。后者包括大陆北部草原和苔原，以及湖泊和近海岛屿的形成。虽然一些物种进化出了固定的适应特定栖息地的能力，但其他物种发展出了灵活的适应能力，使它们能够栖息在广泛的生态位，并在重大的环境变化中生存下来。对短期（迁徙和季节性）栖息地变化的适应可能在哺乳动物物种对第四纪长期周期性变化的预适应中发挥了作用。化石证据表明，数千年的环境变化足以产生亚物种，但物种形成通常需要10万到几十万年，尽管也有较短或较长的例外。类群在具有强选择机制的环境中持续存在，可能是促使重大适应性变化的重要因素。个别的米兰科维奇循环不一定与这一过程有关，但它们通常也不会抑制哺乳动物的进化变化：许多进化分歧建立在多个气候循环之上。物种形成时间的推断需要化石和现代表型和育种数据的输入，以补充和限制线粒体DNA合并日期，这些日期通常高估了分类分化日期和物种形成的持续时间。对气候变化的迁移和进化反应不是相互排斥的，相反，可能是协同的。最后，初步分析表明，与新近纪相比，第四纪的动物更替（包括物种形成的一个重要因素）有所增加，至少在某些生物群系中是如此。宏观进化的物种选择或分选显然导致了现代哺乳动物群中充满了快速繁殖和/或适应性广泛的物种。
The Quaternary was a time of extensive evolution among mammals. Most living species arose at this time, and many of them show adaptations to peculiarly Quaternary environments. The latter include continental northern steppe and tundra, and the formation of lakes and offshore islands. Although some species evolved fixed adaptations to specialist habitats, others developed flexible adaptations enabling them to inhabit broad niches and to survive major environmental changes. Adaptation to short-term (migratory and seasonal) habitat change probably played a part in pre-adapting mammal species to the longer-term cyclical changes of the Quaternary. Fossil evidence indicates that environmental changes of the order of thousands of years have been sufficient to produce subspeciation, but speciation has typically required one hundred thousand to a few hundred thousand years, although there are both shorter and longer exceptions. The persistence of taxa in environments imposing strong selective regimes may have been important in forcing major adaptive change. Individual Milankovitch cycles are not necessarily implicated in this process, but nor did they generally inhibit evolutionary change among mammals: many evolutionary divergences built over multiple climatic cycles. Deduction of speciation timing requires input from fossils and modern phenotypic and breeding data, to complement and constrain mitochondrial DNA coalescence dates which appear commonly to overestimate taxic divergence dates and durations of speciation. Migrational and evolutionary responses to climate change are not mutually exclusive but, on the contrary, may be synergistic. Finally, preliminary analysis suggests that faunal turnover, including an important element of speciation, was elevated in the Quaternary compared with the Neogene, at least in some biomes. Macroevolutionary species selection or sorting has apparently resulted in a modern mammalian fauna enriched with fast-reproducing and/or adaptively generalist species.