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初中体育田径教学策略研究
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作者 傅硕 《新教育时代电子杂志(学生版)》 2019年第9期98-98,共1页
初中体育教学中,田径是主要项目,其教学目标是提高学生体质。文章旨在研究如何提升初中田径运动的教学水平,首先阐述其重要意义,然后分析当前田径教学中存在的问题,最后对此探讨教学策略。
关键词 初中体育 田径教学策略 生分意义 问题
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Phylogeny of the Labeoninae (Teleostei, Cypriniformes) based on nuclear DNA sequences and implications on character evolution and biogeography 被引量:2
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作者 Lanping ZHENG Junxing YANG Xiaoyong CHEN 《Current Zoology》 SCIE CAS CSCD 2012年第6期837-850,共14页
Abstract The Labeoninae is a subfamily of the family Cyprinidae, Order Cypriniformes. Oromandibular morphology within the Labeoninae is the greatest among cyprinid fishes. Although several phylogenetic studies about l... Abstract The Labeoninae is a subfamily of the family Cyprinidae, Order Cypriniformes. Oromandibular morphology within the Labeoninae is the greatest among cyprinid fishes. Although several phylogenetic studies about labeonines have been undertaken the results have been inconsistent and a comprehensive phylogeny is needed. Further, an incongruence between morphological and molecular phylogeny requires a systematic exploration of the significance of morphological characters on the basis of the molecular phylogeny. In this study, a total of 292 nucleotide sequences from 73 individuals (representing 24 genera and 73 species) of Labeoninae were analyzed. The results of the phylogenetic analysis indicate that there are four major clades within Labeoninae and three monophyletic lineages within the fourth clade. Results of the character evolution show that all oromandibular morphological characters are homoplastically distributed on the molecular phylogenetic tree and suggests that these characters evolved several times during the history of labeonines. In particular, the labeonine, a specific disc on the lower lip, has been acquired three times and reversed twice. These morphological characters do not have systematic significance but can be useful for taxonomy. The results of biogeography suggest that the Labeoninae originated from Southeast Asia and separately dispersed to Africa, East Asia and South Asia. 展开更多
关键词 PHYLOGENY Character evolution BIOGEOGRAPHY LABEONINAE
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