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The importance of evolutionary parallelisms and their differences from evolutionary convergences have been historically underappreciated, as recently noticed in Gould's last book `The structure of evolutionary history'. In that book, Gould make an effort to distinguish and to reinterpret these concepts in the light of the new discoveries of the last decades on developmental biology and genetics, presenting the elegant metaphor of `Pharaonic bricks versus Corinthian columns'. In this paper I will briefly discuss these concepts, and will argue that, despite the advances that have been made to define them in theory, it is rather hard to differentiate them in a practical phylogenetic context. In order to do so, I will provide some few examples from my own empirical studies on the last years of one of the most morphologically and taxonomically diverse groups of Vertebrates, the catfishes.  相似文献   
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本文对烟台海域海月水母水母体阶段伞径、腕长及体重的生长规律进行了研究,并首次对其生长过程中水管系统的发育进行了观察。结果表明,在人工培养条件下,海月水母体重(W)与伞径(D:15~150㎜)呈幂函数增长;腕长(L)与伞径(D)呈线性关系;伞径生长曲线方程为:Dt = 4×10-6t4-0.0014t3 0.1087t2 0.5079t 9.428 (R2=0.9993)。。海月水母初生碟状体出现主辐管与间辐管,3日龄时碟状体出现从辐管,11日龄时出现环管、分离点。随着水母的生长,伞径增大,水管系统的分离点数与聚合点数逐渐增多,成熟时1/4伞部分离点数最多为66个,聚合点数最多为32个。  相似文献   
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