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1.
亚·彼·卡尔宾斯基迈着矫健的步伐走近了宿营地。他理了理乌黑浓密的头发,瞧着面前摆着的乌拉尔亚丁斯基组地层里发现的海洋软体动物的贝壳。一丝惬意的微笑掠过他的面庞。他对于搜集了那样多各种各样的菊石贝壳感到高兴。通过对菊石的研究,揭露距今几亿年以前海洋中生命的秘密。这个任务是不轻松的。卡尔宾斯基握着一只外表有几分象现代蜗牛的菊石贝壳,一面用放大镜察看着,一面象外科医生一样,在动着最精细的“手术”。他小心地弄断贝壳螺旋圈外部的几个小块,暴露出内壁。他看到了贝壳中一个接一个的小室。小室与小室之间有隔膜隔开。被他敲破的第一个外方的小室是最大的。其中曾经居住过菊石——已绝灭了的头足类的软体。头足类  相似文献   

2.
本文主要描述了南海南沙群岛永暑礁南永3井微型腹足类盘足目,新腹足目,异旋目,豆楯目和囊舌目共70个种。这些种类个体非常微小,大多数小于2mm。绝大多数种类为典型的热带海区分子,它们具有广泛的地理分布。本文按Okutani(2000)分类系统进行了分类。绝大多数种类系南沙群岛海区首次记录。  相似文献   

3.
本文简要介绍衣原体目分类的最近进展,包括分类原则、新分离出衣原体株的鉴定和分类以及新发现的新科和新种。  相似文献   

4.
介绍单孔目和有袋目哺乳动物的形态特征、分类地位、全球分布、栖息环境、生活习性、食性和生殖方式等.并涉及趋同进化、趋异进化和保护生物学等基本知识.  相似文献   

5.
香港菊石     
韦和 《化石》2001,(2):30-30
第一件以世界名港———香港地名命名的化石属首推香港菊石(Hongkongites)。1920年英人韩雷(Heanly)博士在香港新界东北赤门海峡北岸凤凰笏小海湾西南不远海边的赤褐色砂质页岩中挖获。1922年韩雷将菊石标本交当时的中国地质调查所古生物学家、北大理学院葛利普(Grabau)教授研究 ,次年葛氏认为化石应归属盔菊石类(Hoplitid) ,可能为韦氏盔菊石一个变种。因韦氏盔菊石产自喜马拉雅地区海相早白垩世地层 ,于是在广布中生代火山岩、花岗岩地区的香港九龙第一次报导了有地中海型海相中生代地层…  相似文献   

6.
鲸目分类的重大修改比利时布鲁塞尔自由大学的米契尔·密林柯维奇及其在美国纽约州大学的共同工作者,在分析鲸类和海豚类(鲸目)的脱氧核糖核酸(DNA)后宣称,它们的分类应加以彻底修改。理想的动物分类应该反映动物是如何进化的。化石能为此提供一个指证,但分类通...  相似文献   

7.
布尼亚病毒目新分类概述   总被引:1,自引:0,他引:1  
布尼亚病毒目中许多病毒是新发现的, 而且对人类健康构成威胁或潜在威胁。本文结合国际病毒分类委员会(ICTV) 2017年第十次报告, 针对新列的布尼亚病毒目的最新分类系统, 总结了该类病毒 ICTV 分类的历史变化情况, 对其下属各病毒科的分类、中英文定名、代表种、病毒形态、病毒基因组结构、编码蛋白、病毒主要传播媒介、病毒感染宿主、地理分布、理化特性等进行了介绍, 并且基于病毒基因组的编码RdRp的基因序列对9个科13个属的布尼亚病毒做了系统发育分析。  相似文献   

8.
基于web的等翅目昆虫分类系统的设计和开发   总被引:4,自引:2,他引:4  
以《中国动物志·昆虫纲·第十七卷·等翅目》一书资料为基础,结合白蚁分类的最新成果,开发了基于web的等翅目昆虫分类系统。本系统由白蚁分类资料显示子系统、白蚁分类资料检索子系统、后台数据库在线管理子系统和白蚁种类鉴定子系统等4个功能模块组成。用户通过Internet网络,可实现白蚁分类资料的查询与未知种类的鉴定。本系统的开发,为我国白蚁种类的识别和相关信息的共享提供了快捷、高效的网络工具。这是计算机信息处理技术与白蚁形态分类学的有机结合,是利用计算机技术提高生物形态学研究、教学效率的一种新途径。  相似文献   

9.
全齿目(Pantodonta)和裂齿“目”(Tillodontia)是早第三纪时分布于北半球的古老有蹄类。关于它们的分类位置曾有过不少争论,但最近一些年来似乎已有了定论,一般都把它们作为哺乳动物纲的两个独立的目,对每个目的内容也很少有重大争议。最近几年,我国发现了大量的古新统全齿类和一些裂齿类的化石。这些化石的时代较早,并具有许多重要特征,对于这两个类群的起源、分布与系统关系及分类提出了一些新的问题。在本文中,我们根据近年来亚洲、主要是我国南方红层中新发现的古新世及始新世化石,对全齿目和裂齿目系统发育方面存在问题的现状与历史过程,作简略的评述,并对这两大类动物的各高级分类阶元(目、亚目、科)的起源与系统发育关系进行探讨,提出一个新的分类系统。  相似文献   

10.
世界鸡形目鸟类   总被引:2,自引:0,他引:2  
介绍了世界上鸡形目鸟类的分布、分类、形态特点、栖地类型及生活习性。世界鸡形目鸟类分为7个科,共计281种。中国鸡形目鸟类包括松鸡科8种和雉科52种。介绍了中国鸡形目鸟类种的分类等方面的一些最新进展。  相似文献   

11.
12.
We compared the cardiovascular effects evoked in conscious dogs by 1) submaximal exercise; 2) infusion of dobutamine (40 micrograms X kg-1 X min-1); and 3) infusion of a combination of atropine (0.15 mg/kg), norepinephrine (0.19 micrograms X kg-1 X min-1), and epinephrine (0.05 micrograms X kg-1 X min-1). Myocardial O2 demand, as estimated by the double product (heart rate X systolic blood pressure), was similar during all three interventions. Cardiac output and heart rate increased significantly (P less than 0.05) during each of the three interventions. Arteriovenous O2 difference and total body O2 consumption, however, increased only during submaximal exercise. Although myocardial blood flow increased similarly during each of the three interventions, blood flow to skeletal muscle and the tongue increased only during exercise. Exercise and the combined infusion of atropine, norepinephrine, and epinephrine produced similar increases in blood flow to the diaphragm and similar decreases in blood flow to the stomach. These changes in blood flow were associated with appropriate changes in vascular resistance. Additionally, blood flow to the brain, kidney, adrenal glands, liver, and intestine did not change during any of the three interventions. Thus, in dogs, submaximal exercise, infusion of dobutamine, and infusion of a combination of atropine, norepinephrine, and epinephrine to evoke a given level of estimated myocardial O2 consumption produce similar increases in cardiac output, heart rate, and myocardial blood flow. In contrast, the changes in total body O2 consumption, arteriovenous O2 difference, regional blood flow, and regional vascular resistance that occur during each of these three interventions are different.  相似文献   

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14.
A review is presented of issues relevant to the definition, measurement, and classification of stimuli, situations, and environments. Problems such as the lack of adequate definitions of concepts, error and bias in measurement procedures, confusion between measurement of a concept and measurement of its behavioral effects, and the lack of agreement among alternative measures are emphasized. It is suggested that concepts be defined in terms of objective characteristics while allowing for the study of the transactional relationship between organism and environment. The work of the ethologists in defining stimuli while studying their relationship to different organismic states and situational contexts is emphasized in this regard. Following Brunswik, it is also suggested that wherever possible there be a representative sampling of variables in natural settings. Note from the editors: From time to time, Human Ecology will publish a review article. Our first in this series is a review by a psychologist of basic definitional and conceptual problems in environmental studies.This paper was prepared while the author was a Visiting Research Fellow at the Educational Testing Service. The support of ETS and my colleagues in the Division of Psychological Studies is gratefully acknowledged. The review was also supported in part by a grant from the Rutgers University Research Council.  相似文献   

15.
Indians, Markets, and Rainforests: Theory, Methods, and Analysis. Ricardo A. Godoy. New York: Columbia University Press, 2001. 274 pp.  相似文献   

16.
2-Dimethylaminomethylene-1-benzosuberone 1 was coupled with diazotized aniline derivatives to afford a series of the hitherto unreported 2-arylazo-1-benzosuberones 3ai. The tautomeric structure and the effect of substituents on the tautomeric form (s) of the products 3ai were discussed. Similar coupling of the enaminone 1 with diazonium salts of heterocyclic amines gave the respective fused azolotriazino-benzosuberones. Some of the newly synthesized compounds showed potent antimicrobial, anti-HCV, antioxidant, antitumor (as topoisomerase I inhibitors), and antimicrobial activities.  相似文献   

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19.
Mones Berman's untimely death on 12 August 1982 put an end to his work in the development of theoretical biology. Arguments are examined, and it is concluded that a formal theory of lipoprotein metabolism flourished and expanded under the guidance of Dr. Berman. Not many scientists in the field of biology spend a major portion of their energies on theoretical work xxx was outstanding because of his early decision to follow the theoretical path.  相似文献   

20.
Pericytes, the mural cells of blood microvessels, have recently come into focus as regulators of vascular morphogenesis and function during development, cardiovascular homeostasis, and disease. Pericytes are implicated in the development of diabetic retinopathy and tissue fibrosis, and they are potential stromal targets for cancer therapy. Some pericytes are probably mesenchymal stem or progenitor cells, which give rise to adipocytes, cartilage, bone, and muscle. However, there is still confusion about the identity, ontogeny, and progeny of pericytes. Here, we review the history of these investigations, indicate emerging concepts, and point out problems and promise in the field of pericyte biology.  相似文献   

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