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关键词： lens   evolution   Ciona   amphioxus   crystallin   placode  

摘要： Several animal lineages, including the vertebrates, have evolved sophisticated eyes with lenses that refract light to generate an image. The nearest invertebrate relatives of the vertebrates, such as the ascidians (sea squirts) and amphioxus, have only basic light detecting organs, leading to the widely-held view that the vertebrate lens is an innovation that evolved in early vertebrates. From an embryological perspective the lens is different from the rest of the eye, in that the eye is primarily of neural origin while the lens derives from a non-neural ectodermal placode which invaginates into the developing eye. How such an organ could have evolved has attracted much speculation. Recently, however, molecular developmental studies of sea squirts have started to suggest a possible evolutionary origin for the lens. First, studies of the Pax, Six, Eya and other gene families have indicated that sea squirts have areas of non-neural ectoderm homologous to placodes, suggesting an origin for the embryological characteristics of the lens. Second, the evolution and regulation of the beta gamma-crystallins has been studied. These form one of the key crystallin gene families responsible for the transparency of the lens, and regulatory conservation between the beta gamma-crystallin gene in the sea squirt Ciona intestinalis and the vertebrate visual system has been experimentally demonstrated. These data, together with knowledge of the morphological, physiological and gene expression similarities between the C. intestinalis ocellus and vertebrate retina, have led us to propose a hypothesis for the evolution of the vertebrate lens and integrated vertebrate eye via the co-option and combination of ancient gene regulatory networks;one controlling morphogenetic aspects of lens development and one controlling the expression of a gene family responsible for the biophysical properties of the lens, with the components of the retina having evolved from an ancestral photoreceptive organ

关键词： Animals   Fossils   History, Ancient   Mammals/anatomy & histology   Mammals/classification   Mammals/genetics   Mammals/physiology   Mongolia   Phylogeny   Phylogeny   Placenta   Time Factors  

摘要： The article cites a study that tackles the evolutionary history of mammals through molecular analyses and morphological studies of fossils. Researchers announce the discovery of a well-preserved mammal from Mongolia dated at between 71 and 75 million years old. Analyses place direct ancestry of mammals near the Cretaceous-Tertiary boundary. Three main groups of living mammal are also recognized.

关键词： 高师   《动物生物学》课程   口试   教学改革  

摘要： 从教学实践出发,对师范生物教育专业《动物生物学》课程考核进行改革,在传统考核方式的基础上增加口试的考核形式,提出口试考核能有效地弥补传统考核方式的不足,杜绝笔试中存在的一些弊端,实现对学生的全面评价。同时对学生综合素质的提升及形成良好的学习风气也有很好的促进作用。

关键词： 欧亚大陆   大哺乳动物化石   地点覆盖度   集合群落   地质时期动物群  

摘要： 在古生物群落中新近出现的地点覆盖度或发生率的概念,以及对生物集合种群的空间动态学的深入了解,使古生物学和现代生物学的联系更加紧密。集合群落的概念以及地质时期动物群的古生物学认识显示,将古生物学和生态学结合在一起是大有希望的。评述了目前对这些概念的理解,并以欧亚大陆大型食草动物群落的发育作为范例,介绍了运用这些理论来研究化石记录的方法。研究结果表明,化石记录中种群覆盖度的研究可以在以化石为基础的进化研究和以现生有机体为基础的进化研究之间架起一座桥梁。地点覆盖度最大的类群,像现代生态学中发生率最大的类群一样,往往是地理分布最广泛、在当地最丰富的类群。

关键词： 双峰驼   单峰驼   美洲驼   羊驼   原驼   骆马  

摘要： 对骆驼科的3属6种动物,双峰驼、美洲驼、羊驼、原驼和骆马的地理分布、形态特征、饮食习性、行为学、生殖特性及生存环境等进行了系统的阐述,以期为人们在研究骆驼科动物的生物学特性时提供参考。

关键词： supporting   mostly   summary  

摘要： The papers presented in this special issue of Integrative Zoology(and over the next two issues)were mostly presented at the Third International Conference on Rodent Biology and Management(ICRBM)that was held in 28 Aug−1 Sept 2006 in Hanoi,Vietnam(for a summary of the conference,see the summary report by *** in Integrative Zoology,1(4),194–195).The conference attracted an international audience of 130 participants from 35 countries,with a good mix of developed and developing countries,and students and researchers,with a particular emphasis on supporting scientists and students from developing *** conference provided an opportunity for all participants to refresh and update their knowledge of scientific,technical and extension developments in the field of rodent *** were approximately 110 spoken papers and 50 posters over the 4 days of the conference.

关键词： 动物微生物学   网络课程   应用体会  

摘要： 动物微生物学是一门综合性很强的专业基础课程,该课程教学水平的高低,对动物医学、动物科学及相近专业学生的业务素质的培养起着至关重要的作用。在教学改革中我们强调动物微生物学网络课程的建设和应用,通过网络课程的应用实践,极大地丰富了我们的教学内容,提高了教学队伍的教学方法,加强了学生自主学习的能力,增强了教学资源的共享性,同时带动了其它课程的教学改革建设。

关键词： 分子生物学   动物寄生虫学   相互关系  

摘要： 动物寄生虫的分子生物学研究始于20世纪90年代中期,虽然起步较晚,但进展极快。近10年来,研究广度已涉及所有重要的寄生原虫,并已扩展到了具有重要公共卫生意义的部分寄生蠕虫,研究深度已进入寄生虫的基因序列测定分析、分类比对鉴定、诊断方法的建立和免疫学研究领域,建立了近50种寄生虫的cDNA文库。我国鸡球虫、旋毛虫等虫种的分子生物学研究达到和接近世界先进水平。这些研究成果和技术水平,已为动物寄生虫病的研究和防控工作展示了新的前景。

关键词： 中国科学院   动物生态与保护生物学   重点实验室  

摘要： 野生动物作为自然生态系统的重要组成部分。对维持生态系统的平衡发挥着重要作用。然而，随着人口膨胀和经济高速发展所带来的环境压力，生态系统正受到严重的损害，导致许多物种已经灭绝，更多的物种也正处于濒危状态。我国是濒危动物分布大国，巨大的人口和环境压力、高速的经济发展对资源需求的日益增加和利用不当，引起的生态环境日益恶化，致使15％～20％的物种处于濒危状态。

关键词： 动物学：生物学-教育实习-高等学校-教学参考资料