Department of Zoology and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, Canada.
J Evol Biol. 2012 Sep;25(9):1902-10. doi: 10.1111/j.1420-9101.2012.02566.x. Epub 2012 Jul 11.
Conceptual models of adaptive radiation predict that competitive interactions among species will result in an early burst of speciation and trait evolution followed by a slowdown in diversification rates. Empirical studies often show early accumulation of lineages in phylogenetic trees, but usually fail to detect early bursts of phenotypic evolution. We use an evolutionary simulation model to assemble food webs through adaptive radiation, and examine patterns in the resulting phylogenetic trees and species' traits (body size and trophic position). We find that when foraging trade-offs result in food webs where all species occupy integer trophic levels, lineage diversity and trait disparity are concentrated early in the tree, consistent with the early burst model. In contrast, in food webs in which many omnivorous species feed at multiple trophic levels, high levels of turnover of species' identities and traits tend to eliminate the early burst signal. These results suggest testable predictions about how the niche structure of ecological communities may be reflected by macroevolutionary patterns.
适应辐射的概念模型预测，物种间的竞争相互作用将导致物种形成和特征进化的早期爆发，然后是多样化率的减缓。实证研究经常显示出系统发育树上早期的谱系积累，但通常未能检测到表型进化的早期爆发。我们使用进化模拟模型通过适应辐射组装食物网，并检查由此产生的系统发育树和物种特征（体型和营养位置）的模式。我们发现，当觅食权衡导致所有物种都占据整数营养水平的食物网时，谱系多样性和特征差异集中在树的早期，与早期爆发模型一致。相比之下，在许多杂食性物种在多个营养水平上觅食的食物网中，物种身份和特征的高周转率往往会消除早期爆发的信号。这些结果表明，可以对生态群落的生态位结构如何反映宏观进化模式提出可检验的预测。
