Why are arthropods segmented?
Why are arthropods segmented?
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DOI：
10.1046/j.1525-142x.2001.01041.x
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发表时间：
2001-09-01
影响因子：
2.9
通讯作者：
Budd, GE
中科院分区：
文献类型：
--
作者：
Budd, GE
在最近的文献中，作为生物体的一种属性的节段性越来越多地被讨论，因为(1)新的系统发育表明，传统上被认为是节段性的生物体可能位于不同的支系中；(2)节段性发育的分子基础已经被大量研究；(3)各种关于双边起源的理论将节段性作为原始特征加以重视；(4)最近强调了模块化作为进化主题的重要性。然而，分割的定义和范围是高度模糊的，而且通常是类型学的。在这里，分割被视为器官的属性，而不是生物体的属性。仅根据化石记录和现存的真节肢动物、迟滞动物和甲壳动物，对节肢动物表皮的进化进行了研究。可以看到，它已经被分割成一个复杂的路径，需要转移功能、冗余和相关器官的变化。这种复杂性必然反映所涉及变化的遗传基础，并在一定程度上高于遗传基础。在发育进化的背景下，进化功能形态相对较少被考虑，但在确定这种进化发生的框架方面可能发挥重要作用。
Segmentation as an attribute of organisms is being increasingly discussed in the recent literature because (1) new phylogenies suggest that organisms classically considered to be segmented may lie in separate clades; (2) the molecular basis of segmental development has been much studied; (3) various theories of bilaterian origins place weight on segmentation as a primitive character; (4) there has been recent stress on the importance of modularity as an evolutionary topic. However, the definition and extent of segmentation are highly ambiguous and usually typological. Here, segmentation is regarded as an attribute of organs, not organisms. The evolution of just one system, the arthropod epidermis, is examined on the basis of the fossil record and the extant euarthropods, tardigrades, and onychophorans. It may be seen to have become segmented in a complex pathway that necessitated shifts in function, redundancy, and changes in associated organs. This complexity must inevitably reflect on, and to an extent have primacy over, the genetic basis for the changes involved. Evolutionary functional morphology has been relatively little considered in the context of the evolution of development, but may play an important role in defining the framework within which this evolution occurs.