Division of Ecology and Evolution, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
Division of Ecology and Evolution, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia.
Proc Biol Sci. 2018 Oct 17;285(1889):20181474. doi: 10.1098/rspb.2018.1474.
On deep time scales, changing climatic trends can have a predictable influence on macroevolution. From evidence of mass extinctions, we know that rapid climatic oscillations can indirectly open niche space and precipitate adaptive radiation, changing the course of ecological diversification. These dramatic shifts in the global climate, however, are rare events relative to extended periods of protracted climate change and biome turnover. It remains unclear whether during gradually changing periods, shifting habitats may instead promote non-adaptive speciation by facilitating allopatry and phenotypic conservatism. Using fossil-calibrated, species-level phylogenies for five Australian radiations comprising more than 800 species, we investigated temporal trends in biogeography and body size evolution. Here, we demonstrate that gradual Miocene cooling and aridification correlates with the restricted phenotypic diversification of multiple ecologically diverse vertebrate groups. This probably occurred as species ranges became fractured and isolated during continental biome restructuring, encouraging a shift towards conservatism in body size evolution. Our results provide further evidence that abiotic changes, not only biotic interactions, may act as selective forces influencing phenotypic macroevolution.
在长时间尺度上，气候变化趋势可能会对宏观进化产生可预测的影响。从大规模灭绝的证据中，我们知道快速的气候振荡可以间接地开辟生态位空间并引发适应性辐射，从而改变生态多样化的进程。然而，与长时间的持续气候变化和生物区系更替相比，这些全球气候的剧烈变化是罕见事件。目前尚不清楚在逐渐变化的时期，不断变化的栖息地是否会通过促进异地和表型保守性而促进非适应性物种形成。我们使用经过化石校准的、包含 800 多种物种的五个澳大利亚辐射物种水平系统发育，研究了生物地理学和体型进化的时间趋势。在这里，我们证明渐新世的冷却和干旱化与多个生态多样化的脊椎动物群的受限表型多样化相关。这可能是由于物种范围在大陆生物区系重构过程中破裂和隔离，导致体型进化向保守性转变。我们的结果进一步表明，影响表型宏观进化的选择力量可能不仅是生物相互作用，还有生物变化。
