西北大学两项国家自然科学基金重点项目中期检查、结题验收均获优秀

2013年3月10-11日,国家自然科学基金委员会地球科学部在北京召开了重点项目中期检查和结题验收会议,分别对2008年开题的62个重点项目和2010年开题的66个重点项目进行了结题验收和中期检     

从未谋面的近邻——记鱇（魚良）自鱼与大头鲤

抚仙湖又名澄江海，坐落在云南省中部澄江、江川、华宁三县间，明水面积212平方公里，湖面海拔1875米，深达155米。     

华南地区湖南省芙蓉统(上寒武统)的古蠕虫骨片:个体生长对表皮骨片形态的影响(英文)

报道最近发现的华南地区湖南省芙蓉统(上寒武统)三维保存的古蠕虫骨片碎片。描述两个新的形态属和两个新的形态种:Hunanoscolex campus新属新种和Ornatoscolex hunanensis新属新种。大部分标本属于幼体阶段。Hunanoscolex campus体节宽度的巨大差异显示其处于生长发育阶段,因此可以对个体生长对表皮骨片形态的影响进行研究。虫体生长主要依靠增加单个体节中骨片的数量。位于同一排中的大骨板排列变得疏松。新增加的小骨板和微骨板大小和纹饰基本不变,但大骨板的纹饰可能存在变化。这些观察结果有助于更好地理解古蠕虫骨片的种内差异,从而可能提高形态种属分类的准确性。     

Exceptionally preserved brachiopods from the Chengjiang Lagerst（a｜¨）tte（Yunnan,China）：Perspectives on the Cambrian explosion of metazoans

The Cambrian explosion was coined to describe the geologically sudden appearance of numerous bilaterian body plans（Phyla）around the Ediacaran-Cambrian transition,around 565-520million years ago.Many explanations and conjectures have been postulated in order to explain the pattern and duration of this explosive radiation of many different phyla of early metazoans.Here,we focus on the evolution of a phylum of marine suspension-feeding animals—the brachiopods,as exemplified by the exceptionally preserved taxa from the celebrated Chengjiang Konservat Lagerst（a｜¨）tte（Yunnan,China）.The abundant soft-bodied preservation at these fossil quarries gives us the only firm insights into what brachiopods looked like and how they functioned and lived when they first appeared on the Earth.Studies of Chengjiang brachiopods demonstrate that the early animals developed a remarkably varied organization of tissues and organs shortly after the onset of Cambrian explosion.In the marine suspension-feeding brachiopods,most importantly the tentaculate feeding structure of early brachiopods is already differentiated into two shapes of lophophore,anteriorly coiled（spiralled）and posteriorly arching tentacle crowns and the unique latter type was previously not documented from fossil and living brachiopods.Also unlike any known Recent brachiopod,all the known Cambrian brachiopods from Chengjiang have an open digestive tract that was disposed either as a Ushaped gut in linguliform and stem group brachiopods,or straight gut with a posterior anus in some calcareous-shelled stocks.Moreover,in contrast toliving lingulids,all the Cambrian brachiopods have an epibenthic lifestyle either cemented by a ventral valve or attached by variable pedicles to establish complex ecological community encompassing primary tierers and variable secondary tierers.It is therefore assumed that brachiopods were the first benthic metazoan that achieved their success in ecological stratification and tiering complexity by late Atdabanian.The setae are also important for the brachiopod suspension-feeding life style,and in the Chengjiang braehiopods they include two types cilia-like and spine-like setae.The mantle canals of different braehiopod species are also distinctly variable in arrangement,mainly disposed in pinnate,baeulate and peripheral conditions.Of these,the peripheral disposition of mantle canals is for the first time proposed here so as to differentiate from the bifurcate condition in recent lingulids in that the former is devoid of posteriorly extending main trunks of sinus,but possesses a diverging dorsal vascula media in dichotomy.     

具有竞争机理局部稳定的两种群模型及其保解析性

通过对一类具有竞争机理局部稳定的两种相经作用生态种群模型保解析性的讨论，进一步将生态环境系统的调控严谨化，给一类生态系统的动态分析与调控优化模拟了一种有价值的方法与手段，这不仅对于两种互相竞争和互惠互存的生态系统的建模与分析具有重要意义，而且对于更为复杂的生态环境系统的动态分析与宏观调控也具有较大的指导作用与应用价值。     

竹节虫的“前世今生”

人类出现至今已经有几百万年的历史,然而竹节虫的进化之旅比我们还要早2亿多年!直至今日,它们仍然以形色兼备的拟态本领活跃在这颗蓝色星球上,实在让人叹服。它们的祖先又有着怎样的拟态本领?竹节虫全身似枝干儿,又细又长,中间有节,两根触角笔直地向前伸展,三对细长的足好似枝干的分叉,这身型简直是对自己名字的完美诠释。如果说"竹节虫"这名字形象具体、生动传神,那它的希腊名"phasma"(意为"幻影")则更让人浮想联翩,从竹节虫形态的惟     

米仓山澄江期基性侵入杂岩特征及其成因探讨

通过米仓山地区岩浆杂岩的综合调查研究，采用同源岩浆演化序列理论，首次确认了区内澄江期侵入杂岩的存在。云雾山超单元即为该期早期基性岩浆作用的产物，同位素年龄介于７７６．５～７６６．７Ｍａ之间，由四个单元组成，具富Ｔｉ，Ａｌ，Ｆｅ的特征，其ＳＩ＝４０～１５，ＤＩ＝１１～５６，σ＝１．８～３．７；稀土及微量元素特征均显示具良好的同源岩浆演化特点。原始岩浆温度８５０～１１２５℃，成岩压力约０．７１０～０．７５６ＧＰａ，ｆＯ２≥１０－１１，具幔源为主及壳幔混合源的特征，为早震旦世龙门山—米仓山大陆裂谷作用中期阶段地幔底劈上隆的产物。     

揭秘侏罗纪恐怖虫化石

正昆虫化石中最令人困惑的恐怖虫的神秘面纱,随着道虎沟恐怖虫化石的发现而被慢慢揭开,原先认为恐怖虫是带毛恐龙身上寄生虫的观点受到质疑。昆虫是动物界多样性最丰富的类群,而昆虫纲几乎所有现生昆虫的目都可在遥远的中生代(距今2.5亿到6500万年前)找到它们祖先的化石。在我国内蒙古自治区距今约1.65亿年前的中侏罗世道虎沟动物群里,大约已发现25个现生昆虫目之祖先化石。该动物群是世界中生代昆虫多样性最丰富的动物群。除现生昆虫目以外,还存在一些今已灭绝的昆虫,多出现于昆虫演化初期的石炭纪(距今3.6亿到3亿年前)和     

一个中元古代具壳后生动物群—“洛南生物群”的初步报道

初步报道产自洛南中元古界洛南群巡检司组底部的以具壳化石为代表的多门类生物组合，经多种方法估算的地质年龄为12亿年，是本世纪中期发现的伊迪卡拉软躯生物群的2倍。由于标本及其图象显示明确的化石属性，年代古老，对于地球后生物早期演化的研究具有划时代的意义。