SPECIES CONCEPT AND TAXONOMIC PRINCIPLES

来源 :Science in China,Ser.B | 被引量 : 0次 | 上传用户:hujie789
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
Based on the species concept of changing versus unchanging, the present work deals with the following two problems: First, why would the taxonomic system reflect evolutionary history? Second, how is this effeeted?Species are changing in the sense that each species has its own characteristics and there is no complete identity between any two species. On the other hand, species are unchanging and each one conserves a set of ancestral characters which allocates its taxonomic position, and this is the reason why the taxonomic system reflects evolutionary history.The taxonomic system is constructed to reflect evolutionary history mainly through the process of character analysis. Combining the viewpoints of cladistics and evolutionary systematics, the writer proposes six rules for character analysis which will provide the basis for analyzing evolutionary history. Based on the species concept of changing versus unchanging, the present work deals with the following two problems: First, why would the taxonomic system reflect evolutionary history? Second, how is this effeeted? Species are changing in the sense that each species has its own characteristics and there is no complete identity between any two species. On the other hand, species are unchanging and each one conserves a set of ancestral characters which and allocate its taxonomic position, and this is the reason why the taxonomic system reflects evolutionary history. system is constructed to reflect evolutionary history mainly through the process of character analysis.
其他文献
LabanacecontrelescontracturesmusculairesTresenergetique(92kilocaloriespour100grammes),laba-nanetient,entoutcaspourlesdietetic... LabanacecontrecontractsmusculairesTresenergetique (92kilocaloriespour100grammes), laba-nanetient, entoutcaspourlesdietetic ..
期刊
目前,轴键加工通常采用先锻毛坯后作刨削加工的方法,这种加工工艺不仅工序繁锁,而且生产效率较低,尤其在加工小轴键时,刨、夹和测量均感困难。针对这类问题,我矿老工人曹文
关于卤族元素的分子与其离子的相互作用而生成某种状态的化合物的研究,是海水化学和海水化工中较有实际意义的课题。其中碘分子与卤离子生成络合物的探讨已有不少报导,但有
草原总是孕育传奇,蒙古草原养育出手持套马杆的牧人,北美草原锻炼出戴宽边帽的牛仔,东非草原是动物主宰的世界……不同类型的草原衍生出不同的旅游产品。中国草原面积大、分
《信天游》 Basic Interests 导演:冯小宁 主演:郭达 刘薇 李鸣 《信天游》讲述的是在中国黄河岸边的老百姓身上发生的故事。片中,纪检委书记梁雨露冒着丢 官甚至失去生命的
听力技巧训练中应注意的几个问题张东昌,邵萍(外语教研室261042)在外语学习中,听力是一项要求高,难度大,技巧性强的能力。人们要想提高听力技能必须具备一定的词汇量,懂得语音、词汇、句法
本文研究了Zr对低Co瓷封合金晶粒长大特性的影响机理、规律及对氩弧焊的作用,经用金相、电镜、扫描电镜、能谱及定量分析、示差热分析、萃取第二相质点X射线结构分析、氩弧焊
KT一930中温抗气体渗碳涂料是无机硅酸盐型的,它无毒,涂敷工艺简便,能在名850-900℃碳氮共渗条件下和930士10’C的渗碳条件下起到抗渗作用。 KT a 930 temperature resistan
本文是一篇关于能在半径方向调整切刃的镗孔工具的专利。在本体的前端部设有滑动导向用的细齿,刀块1、2可沿半径方向导向调节。刀块通过孔并借助紧固螺钉固定在本体上。紧固
我厂从济南第八机床厂新进一台CA41 750空气锤,使用不到半年,空气锤杆发生断裂(见图1)。为防止裂纹扩展,在两端钻φ6孔后,仍未阻止住。经研究决定采用补焊方法。我们经三次