Compiling a morphological character matrix as the basis for a better understanding of the evolution of the metazoan nervous system

点击翻译按钮获取中文摘要

The evolution of the nervous system is one of the most fascinating stories in metazoan phylogeny because the nervous systems itself represents one of the driving forces in the evolution of bauplan complexity and disparity in Metazoa. To better understand the evolution of the nervous system, it is essential to identify detailed neuroanatomical characters and trace their distribution across the metazoan taxa. Only then will it be possible to elucidate the complex evolutionary transformation series of certain characters. The main goal of our proposal is to develop a character matrix encompassing 120 to 150 characters and 120 terminal taxa. The major steps in preparing a matrix of this kind are the conceptualization of characters and the identification of potential homologies. An important starting point will be a glossary of neuroanatomical terms compiled by the PI together with all the co-PIs of the present project. The characters compiled in the matrix will be analyzed separately as well as mapped onto existing phylogenies (on the basis of EST and other molecular data). The phylogeny resulting from the separate analysis will be compared with other metazoan phylogenies in terms of conflict and congruence. The evolution of the nervous system will be discussed on the basis of various phylogenies. The matrix module of the data base Morph D Base permits the collaborative, synchronous and decentralized editing of the character matrix. Nevertheless, to facilitate detailed discussion of the characters, their conceptualization and their homology and to provide a forum for the evaluation of the resulting phylogenies and the final discussion of the evolution of the metazoan nervous system, four workshops including the PI, all co-PIs and selected graduate students or postdocs are planned during the two years of the project. These workshops form the core of the proposed project.