Department of Geosciences and Geography, University of Helsinki, , Helsinki, Finland, Department of Ecology and Evolutionary Biology, University of Tennessee, , Knoxville, TN, USA, Department of Biology, University of New Mexico, , Albuquerque, NM, USA, Department of Anthropology, University of New Mexico, , Albuquerque, NM, USA, Department of Ecology and Evolutionary Biology, University of California, , Santa Cruz, CA, USA, Department of Biology and the Ecology Center, Utah State University, , Logan, UT, USA, School of Biological Sciences, Monash University, , Victoria, Australia, Odum School of Ecology, University of Georgia, , Athens, GA, USA, Santa Fe Institute, , Santa Fe, NM, USA, Department of Paleobiology, Smithsonian Institution, , Washington, DC, USA, School of Earth and Space Exploration, Arizona State University, , Tempe, Arizona, USA, School of Biological Sciences, University of Reading, , Reading, UK, Department of Biological Sciences, University of Calgary, , Calgary, Alberta, Canada, Department of Atmospheric, Oceanic and Earth Sciences, George Mason University, , Fairfax, VA, USA.
Proc Biol Sci. 2014 Apr 16;281(1784):20132049. doi: 10.1098/rspb.2013.2049. Print 2014 Jun 7.
There is accumulating evidence that macroevolutionary patterns of mammal evolution during the Cenozoic follow similar trajectories on different continents. This would suggest that such patterns are strongly determined by global abiotic factors, such as climate, or by basic eco-evolutionary processes such as filling of niches by specialization. The similarity of pattern would be expected to extend to the history of individual clades. Here, we investigate the temporal distribution of maximum size observed within individual orders globally and on separate continents. While the maximum size of individual orders of large land mammals show differences and comprise several families, the times at which orders reach their maximum size over time show strong congruence, peaking in the Middle Eocene, the Oligocene and the Plio-Pleistocene. The Eocene peak occurs when global temperature and land mammal diversity are high and is best explained as a result of niche expansion rather than abiotic forcing. Since the Eocene, there is a significant correlation between maximum size frequency and global temperature proxy. The Oligocene peak is not statistically significant and may in part be due to sampling issues. The peak in the Plio-Pleistocene occurs when global temperature and land mammal diversity are low, it is statistically the most robust one and it is best explained by global cooling. We conclude that the macroevolutionary patterns observed are a result of the interplay between eco-evolutionary processes and abiotic forcing.
越来越多的证据表明，新生代哺乳动物进化的宏观进化模式在不同的大陆上遵循相似的轨迹。这表明，这些模式主要由全球非生物因素（如气候）或基本的生态进化过程（如通过专业化填补生态位）决定。模式的相似性预计将扩展到个别进化枝的历史。在这里，我们研究了全球和各个大陆上个体目内观察到的最大尺寸的时间分布。虽然大型陆地哺乳动物的个体目最大尺寸存在差异，包括几个科，但随着时间的推移，目达到最大尺寸的时间具有很强的一致性，在中始新世、渐新世和上新世-更新世达到峰值。始新世的峰值出现在全球温度和陆地哺乳动物多样性较高的时候，这最好解释为生态位扩张的结果，而不是非生物强迫的结果。自始新世以来，最大尺寸频率与全球温度代用指标之间存在显著相关性。渐新世的峰值不具有统计学意义，部分原因可能是采样问题。上新世-更新世的峰值出现在全球温度和陆地哺乳动物多样性较低的时候，它在统计学上是最稳健的，最好用全球冷却来解释。我们得出的结论是，所观察到的宏观进化模式是生态进化过程和非生物强迫相互作用的结果。
