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1.
化石(孢粉)识别专家系统*   总被引:3,自引:1,他引:2  
一、前言1986年夏,陈丕基等在辽宁西部进行白垩系调查时,于孙家湾组采获一批双壳类化石;同年9月和11月,常征路、蒋福兴和张平安等两次去该化石点补充采集,得到更丰富的标本。这些材料交与笔者研究,鉴定为Nippononaia yanjiensis Gu和Unio yanbianensis Gu,这两个种都曾在吉林东部延吉盆地的铜佛寺组发现过(《中国的瓣鳃类化石》,1976)。在我国的早白垩世地层中,珠蚌类与类三角蚌类(包括日本蚌类)大量共生的现象十分罕见。通常认为,  相似文献   

2.
陕南西乡张家沟剖面寒武系下部统宽川铺组发现了大量特异埋藏化石,这些珍贵化石为三维磷酸盐化精美保存,在探索早期生命起源与演化方面意义重大,也是早寒武世前三叶虫时代生物地层对比的重要依据。本文主要对其中一类保存有软躯体的特异埋藏Olivooides multisulcatus Qian,1977进行描记,该类化石1977年曾在陕西宁强宽川铺生物群首次报道,与本文描记的化石类型相同,产地不同,因而具有地层对比意义。根据在西乡生物群发现的新材料,与Olivooides multisulcatus进行特征对比,对属征及种内变异特征进行了补充。  相似文献   

3.
本文作者对周口店第一、第三及第十三地点的一种化石犬类——变异狼(Canis lupus uariadilis)进行了观察和测量。根据其头骨大小、形态特征以及与中国早期人类共生的情况来看,认为它有可能是从驯化的野生狼导致家畜狗出现的一种祖先类型。  相似文献   

4.
枕骨圆枕的变异   总被引:1,自引:1,他引:0  
张银运波.   《人类学学报》1994,13(4):285-293
对印第安人,阿留申人,华北人和云南人总共507具头骨的枕骨圆枕发育程度进行观察,结果表明枕骨圆枕任一发育级别的出现率在相同人种且性别相同的人群之间并无显著差别,枕骨圆枕的发育程度可以被认为是“遗传标记”。作者认为在化石人类中枕骨圆枕的发育程度会有较大的变异;枕骨圆枕的发育程度不是一个有效的鉴别性状。  相似文献   

5.
刘武  邢松  张银运 《人类学学报》2015,34(4):425-441
以往研究发现,中国直立人化石呈现较大的形态变异。对于这种变异程度及造成变异的原因,在古人类学界有不同的认识。有学者提出在直立人阶段,中国古人类已经呈现明显的区域性差异,但也有人认为这些差异似乎没有规律性。近年,本文作者采用不同方法对若干地点的中国直立人牙齿特征及其变异进行了系列研究,取得了一些新的发现和认识。本文在回顾总结这些研究的基础上,结合对其它一些地点中国直立人牙齿特征的观测对比,对中国直立人牙齿特征表现特点及变异作了进一步的分析。本研究发现,中国直立人牙齿特征具有较大的变异范围。这些变异似可分为两种主要类型,元谋、建始、郧县梅铺、和县牙齿呈现出较多的原始特点,代表一种原始类型;周口店、沂源等地点的标本特征相对进步,表现出更多的典型直立人特征。其它一些地点的直立人化石呈现出混合或中间状态。值得注意的是部分呈现出原始牙齿特征类型的中国直立人的生存年代相对较晚,其牙齿特征的原始性与生存时代不具有对应关系。作者认为中国直立人牙齿特征类型反映了更新世早期和中期不同直立人群的演化状态。原始类型牙齿特征的形成不仅与演化时序性和地理分布有关,还在一定程度上反映了一些中国直立人群的演化隔离。  相似文献   

6.
近来笔者喜欢收藏古生物化石,每逢节假日便外出采集化石。由于有了这个爱好的原故,便对邮票上的古生物化石产生了收藏兴趣。化石邮票作为专题性的收集,对收藏化石标本必定带来许多意想不到的收获,化石邮票的图案具有知识性、史料性和观赏娱乐性。我国邮电部于1958年4月15日发行了一套志号为特双的“中国古生物”的邮票,全套三枚。邮票上的图案分别是“蒿里山三叶虫化石”,“禄丰恐龙化石”,“肿骨鹿化石”(见上图)。笔者最近收集了外国化石邮票,图案分别为“恐龙化石”、“鱼化石”、“鸵鸟化石”、“始祖鸟化石”、“蜘蛛…  相似文献   

7.
王立忠  王正 《化石》2002,(2):25-25
赵汉雄先生在《化石》2001年1期上发表的《染色体变异对物种形成的贡献———非达尔文进化观》一文中 ,为了否证达尔文进化论 ,举了一个例子说 :“鸟类无齿可不是适应性状 ,只须看看水禽吞食大鱼的艰难 ,雀儿对坚果的无奈 ,就可知道自然选择在此没有‘尽职’。古代鸟是有牙齿的 ,可惜这套‘牙齿基因’在一次缺失成种时丢失了 ,缺失不能复得 ,贻害了所有后裔”。笔者认为这一判断不符合实际。形形色色的鸟儿自由自在的生活在特定的环境中 ,没有哪一个因没有牙齿而与环境不相适应。吞食乃特定物种的天性 ,只有获食———特别是获大食的喜…  相似文献   

8.
化石文化     
刘晓峰 《化石》1996,(4):2-3
化石文化刘晓峰化石,大自然赐予人类的珍贵资源之一,历来为人类所关注。化石给人类带来了丰富多彩的生活,并从中创造和累积了独特的文化──化石文化。-、化石文化的含义化石,是经自然作用保存在各地质历史时期岩层中的生物遗体或遗迹。化石文化是人类在发现、认识、...  相似文献   

9.
通过光学显微镜(LM)和扫描电子显微镜(SEM)观察表明,红树(Rhizophora apiculata)花粉粒赤道面的形状为球形-近球形,极面观为圆三角形,偶见圆四方形,3-4孔沟,具有连续的环赤道内孔,花粉外壁的典型纹饰为细网状-皱纹状(microreticulate-rugulate)。作者首次报道红树花粉的多态现象,其花粉外壁纹饰和萌发孔数量存在显著的变异,SEM观察到花粉外壁纹饰的变异主要是孔状(perforate)、皱纹状(rugulate)和穴状(foveolate)等类型,LM观察发现4个萌发孔的花粉变异类型。花粉形态的观察与描述为化石花粉的鉴别提供了不可或缺的对比依据。研究红树的花粉形态和发现多态现象有助于了解红树科红树属的花粉外壁演化。花粉的多态现象表明单个花粉形态特征并不能完全代表种的特征。花粉的分类也应该充分考虑花粉性状的间断和连续性,以期正确认识花粉性状在种群内的变异和变异式样,达到客观认识和正确划分植物种下等级的目的。花粉的多态现象为化石花粉的种类鉴定增加了新的参考信息,作者也讨论了花粉多态现象在植物系统演化和古生态学等研究中的可能价值与意义。  相似文献   

10.
通过光学显微镜(LM)和扫描电子显微镜(SEM)观察表明,红树(Rhizophora a piculata)花粉粒赤道面的形状为球形-近球形,极面观为圆三角形,偶见圆四方形,3-4孔沟,具有连续的环赤道内孔,花粉外壁的典型纹饰为细网状一皱纹状(microreticulate-rugulate)。作者首次报道红树花粉的多态现象,其花粉外壁纹饰和萌发孔数量存在显著的变异,SEM观察到花粉外壁纹饰的变异主要是孔状(perforate)、皱纹状(rugulate)和穴状(foveolate)等类型,LM观察发现4个萌发孔的花粉变异类型。花粉形态的观察与描述为化石花粉的鉴别提供了不可或缺的对比依据。研究红树的花粉形态和发现多态现象有助于了解红树科红树属的花粉外壁演化。花粉的多态现象表明单个花粉形态特征并不能完全代表种的特征。花粉的分类也应该充分考虑花粉性状的间断和连续性,以期正确认识花粉性状在种群内的变异和变异式样,达到客观认识和正确划分植物种下等级的目的。花粉的多态现象为化石花粉的种类鉴定增加了新的参考信息,作者也讨论了花粉多态现象在植物系统演化和古生态学等研究中的可能价值与意义。  相似文献   

11.
本文描述蜻蜒化石3新属,3新种:Rudiaeschna limnobia gen. et sp. nov. (Aeshnidae)、Liogomphus yixianensis gen. et sp. nov. (Gomphidae)、Mesocordulia boreala gen. et sp. nov. (Corduliidae)。所有模式标本均采自辽宁北票晚侏罗世地层中,现保存在中国地质博物馆。  相似文献   

12.
The transgenic (mRen2)27 (Ren2) rat overexpresses mouse renin in extrarenal tissues, causing increased local synthesis of ANG II, oxidative stress, and hypertension. However, little is known about the role of oxidative stress induced by the tissue renin-angiotensin system (RAS) as a contributing factor in pulmonary hypertension (PH). Using male Ren2 rats, we test the hypothesis that lung tissue RAS overexpression and resultant oxidative stress contribute to PH and pulmonary vascular remodeling. Mean arterial pressure (MAP), right ventricular systolic pressure (RVSP), and wall thickness of small pulmonary arteries (PA), as well as intrapulmonary NADPH oxidase activity and subunit protein expression and reactive oxygen species (ROS), were compared in age-matched Ren2 and Sprague-Dawley (SD) rats pretreated with the SOD/catalase mimetic tempol for 21 days. In placebo-treated Ren2 rats, MAP and RVSP, as well as intrapulmonary NADPH oxidase activity and subunits (Nox2, p22phox, and Rac-1) and ROS, were elevated compared with placebo-treated SD rats (P < 0.05). Tempol decreased RVSP (P < 0.05), but not MAP, in Ren2 rats. Tempol also reduced intrapulmonary NADPH oxidase activity, Nox2, p22phox, and Rac-1 protein expression, and ROS in Ren2 rats (P < 0.05). Compared with SD rats, the cross-sectional surface area of small PA was 38% greater (P < 0.001) and luminal surface area was 54% less (P < 0.001) in Ren2 rats. Wall surface area was reduced and luminal area was increased in tempol-treated SD and Ren2 rats compared with untreated controls (P < 0.05). Collectively, the results of this investigation support a seminal role for enhanced tissue RAS/oxidative stress as factors in development of PH and pulmonary vascular remodeling.  相似文献   

13.
The aim of this investigation was to evaluate sex differences in baroreflex and heart rate variability (HRV) dysfunction and indexes of end-organ damage in the TG(mRen2)27 (Ren2) rat, a model of renin overexpression and tissue renin-angiotensin-aldosterone system overactivation. Blood pressure (via telemetric monitoring), blood pressure variability [BPV; SD of systolic blood pressure (SBP)], spontaneous baroreflex sensitivity, HRV [HRV Triangular Index (HRV-TI), standard deviation of the average NN interval (SDNN), low and high frequency power (LF and HF, respectively), and Poincaré plot analysis (SD1, SD2)], and cardiovascular function (pressure-volume loop analysis and proteinuria) were evaluated in male and female 10-wk-old Ren2 and Sprague Dawley rats. The severity of hypertension was greater in Ren2 males (R2-M) than in Ren2 females (R2-F). Increased BPV, suppression of baroreflex gain, decreased HRV, and associated end-organ damage manifested as cardiac dysfunction, myocardial remodeling, elevated proteinuria, and tissue oxidative stress were more pronounced in R2-M compared with R2-F. During the dark cycle, HRV-TI and SDNN were negatively correlated with SBP within R2-M and positively correlated within R2-F; within R2-M, these indexes were also negatively correlated with end-organ damage [left ventricular hypertrophy (LVH)]. Furthermore, within R2-M only, LVH was strongly correlated with indexes of HRV representing predominantly vagal (HF, SD1), but not sympathetic (LF, SD2), variability. These data demonstrated relative protection in females from autonomic dysfunction and end-organ damage associated with elevated blood pressure in the Ren2 model of hypertension.  相似文献   

14.
首次报道印氏卵翅蝗Caryanda yini Mao et Ren,2006的一例偏雄性间性体.该个体总体特征为雄性,特别是雄性外生殖器发育完全,雄性下生殖板锥形,但出现了一些典型的雌性特征:前翅棕色、腹部两侧棕色、第十腹节背板后缘无尾片、肛上板三角形、尾须顶端直;腹内有一条线形动物寄生,未见性腺.推测该间性体的形成可能与线形动物的寄生有关.  相似文献   

15.
Abstract Rudiaeschna limnobia gen. et sp. nov. (Aeshnidae), Liogomphus yixianensis gen. et sp. nov. (Gomphidae) and Mesocordulia boreala gen. et. sp. nov. (Corduliidae) are described and figured. All the specimens are recovered from the Upper Jurassic deposits of Beipiao City, Liaoning Province, China, and now housed in the Geological Museum of China, Beijing.  相似文献   

16.
Wang XM  Ren SX  Chen XS 《ZooKeys》2011,(134):33-63
The genus Serangium Blackburn from China is reviewed. The genus Catanella Miyatake is removed from synonymy with Serangium. Serangium baculum Xiao is transferred to Catanella, as Catanella baculum (Xiao), comb. n. Twelve species of Serangium are described, keyed and illustrated, including eight new species, Serangium magnipunctatum Wang & Ren, sp. n., Serangium trimaculatum Wang & Ren, sp. n., Serangium centrale Wang & Ren, sp. n., Serangium leigongicus Wang & Ren, sp. n., Serangium latilobum Wang & Ren, sp. n., Serangium digitiforme Wang & Ren, sp. n., Serangium dulongjiang Wang, Ren & Chen, sp. n., and Serangium contortum Wang & Ren, sp. n.Serangium punctum Miyatake is newly recorded from China.  相似文献   

17.
This study describes a new approach to targeting clustered genes. Our study began with the establishment of two lines of mice carrying different mutations in either Ren1 or Ren2. These two genes, both encoding renin, span over 40 kb in tandem on chromosome 1. Each gene was mutated by gene targeting to contain loxP sites. These two mutants and Cre transgenic mice were mated to produce offspring carrying the mutant Ren1 and Ren2 genes, as well as the Cre transgene concurrently. Initially, two mutant Ren genes were located on separate chromosomes. Southern analysis of mice from the second generation revealed that the mutant Ren1 and Ren2 were interchromosomally recombined at the loxP sites to produce a new dually mutated allele on the chromosome at the rate of 9.6% (7/73). Thus, interchromosomal recombination can be efficiently programmed by mating as designed using the Cre-loxP system.  相似文献   

18.
Biogenic amine receptors mediate wide-ranging hormonal and modulatory functions in vertebrates, but are largely unknown in primitive invertebrates. In a representative of the most basal multicellular animals possessing a nervous system, the cnidarian Renilla koellikeri, aminergic-like receptors were previously characterized pharmacologically and found to engender control of the animal's bioluminescent and peristaltic reactions. Using degenerate oligonucleotides in a RT-PCR strategy, we obtained a full-length cDNA encoding a polypeptide with typical G protein-coupled receptor (GPCR) characteristics and which displayed a significant degree of sequence similarity (up to 45%) to biogenic amine receptors, particularly dopamine and adrenergic receptors. The new receptor, named Ren1, did not resemble any one specific type of amine GPCR and thus could not be identified on the basis of sequence. Ren1 was expressed transiently and stably in cultured mammalian cells, as demonstrated by immunocytochemistry and western blotting. Functional analysis of transfected HEK293, LTK- and COS-7 cells, based on both cAMP and Ca2+ signalling assays, revealed that Ren1 was not activated by any of the known biogenic amines tested and several related metabolites. The results indicated, however, that cells stably expressing Ren1 contained, on average, an 11-fold higher level of cAMP than the controls, in the absence of agonist stimulation. The high basal cAMP levels were shown to be specific for Ren1 and to vary proportionally with the level of Ren1 expressed in the transfected cells. Taken together, the data suggested that Ren1 was expressed as a constitutively active receptor. Its identification provides a basis for examination of the early evolutionary emergence of GPCRs and their functional properties.  相似文献   

19.
D Tronik  M Ekker  F Rougeon 《Gene》1988,69(1):71-80
The two renin genes of the mouse (Ren1 and Ren2) are expressed at different levels in the submaxillary gland (SMG). In contrast to mice, there is no detectable renin gene expression in the rat SMG. To determine the molecular basis for these different levels of renin expression, we have compared the 5'-flanking regions of the rat and mouse genes. The sequence of mouse, but not rat, genes reveals the presence in Ren1 and Ren2 of a large insertion, probably a new class of transposable elements. A second, apparently unrelated shorter insertion is present only in Ren2. Otherwise, the mouse and rat 5'-flanking sequences are well conserved and resemble the corresponding region of the human Ren gene, indicating that the insertions occurred after the separation of the rat and mouse species but before the duplication of the mouse Ren gene. We suggest that these structural differences may have a role in the differential expression of the Ren genes in mice and other animals.  相似文献   

20.
调查了云南省施甸县木老元乡哈寨村104名“本人”的4个细胞血型系统分布。结果表明,“本人”的ABO血型系统分布特点是,基因频率p(0.3069)〉基因频率q(0.1739);在MNSs血型系统中,基因频率m(0.6538)〉基因频率n(0.3462);在P血型系统中,基因频率P1(0.1798)较低。这些均与我国南方少数民族的分布特点基本相符。与我国大部分地区一样。Rh因型系统的单倍型频率中最高的  相似文献   

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