许多先前的研究将恐龙在进化上的成功归因于它们比其它种系所有的“优越性”,但是研究人员现在说,它们也许仅仅是因为幸运而取得了进化上的成功。相关论文发表在9月12日的《科学》(Science)杂志上。
Stephen Brusatte及其同事对化石记录进行了研究,以决定恐龙与主要竞争者镶嵌踝类初龙在三叠纪的晚期一同进化时它们之间的相互关系。他们的发现披露,与普遍认为的相反,恐龙并非通过生境和资源竞争而取代了初龙成为这个星球上占统治地位的物种。相反,研究人员显示,恐龙与初龙是同时进化的,在恐龙存在的头3 千万年间,它们所占有的生境是相同的。这些结论意味着初龙更可能是因为意外而灭绝,而不是因为竞争性替代的结果。恐龙并非如许多人所认为的注定会取得进化上的成功,它们可能是2 次大规模物种消亡事件中的幸运受益者。(生物谷Bioon.com)
生物谷推荐原始出处:
Science,Vol. 321. no. 5895, pp. 1485 - 1488,Stephen L. Brusatte,Graeme T. Lloyd
Superiority, Competition, and Opportunism in the Evolutionary Radiation of Dinosaurs
Stephen L. Brusatte,* Michael J. Benton, Marcello Ruta, Graeme T. Lloyd
The rise and diversification of the dinosaurs in the Late Triassic, from 230 to 200 million years ago, is a classic example of an evolutionary radiation with supposed competitive replacement. A comparison of evolutionary rates andmorphological disparity of basal dinosaurs and their chief "competitors," the crurotarsan archosaurs, shows thatdinosaurs exhibited lower disparity and an indistinguishable rate of character evolution. The radiation of Triassic archosaurs as a whole is characterized by declining evolutionary rates and increasing disparity, suggesting a decoupling of character evolution from body plan variety. The results strongly suggest that historical contingency, rather than prolonged competition or general "superiority," was the primary factor in the rise of dinosaurs.