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91.
出露于新疆南天山东部的阿尔皮什麦布拉克组属于近岸、富氧、温暖的浅海沉积。该组自上一个世纪三十年代创建以来,有关它的地质时代归属一直存在着争论,作者根据珊瑚(包括四射珊瑚、床板珊瑚和日射珊瑚)、介形类和牙形类等门类化石的综合研究,主张将阿尔皮什麦布拉克组置于下泥盆统下部的洛赫柯夫阶。  相似文献   
92.
Symbiosomes are specific intracellular membrane‐bound vacuoles containing microalgae in a mutualistic Cnidaria (host)–dinoflagellate (symbiont) association. The symbiosome membrane is originally derived from host plasma membranes during phagocytosis of the symbiont; however, its molecular components and functions are not clear. In order to investigate the protein components of the symbiosome membranes, homogenous symbiosomes were isolated from the sea anemone Aiptasia pulchella and their purities and membrane intactness examined by Western blot analysis for host contaminants and microscopic analysis using various fluorescent probes, respectively. Pure and intact symbiosomes were then subjected to biotinylation by a cell impermeant agent (Biotin‐XX sulfosuccinimidyl ester) to label membrane surface proteins. The biotinylated proteins, both Triton X‐100 soluble and insoluble fractions, were subjected to 2‐D SDS‐PAGE and identified by MS using an LC‐nano‐ESI‐MS/MS. A total of 17 proteins were identified. Based on their different subcellular origins and functional categories, it indicates that symbiosome membranes serve as the interface for interaction between host and symbiont by fulfilling several crucial cellular functions such as those of membrane receptors/cell recognition, cytoskeletal remodeling, ATP synthesis/proton homeostasis, transporters, stress responses/chaperones, and anti‐apoptosis. The results of proteomic analysis not only indicate the molecular identity of the symbiosome membrane, but also provide insight into the possible role of symbiosome membranes during the endosymbiotic association.  相似文献   
93.
自林启彬先生1978年命名了我国第一个古生代昆虫至今, 中国学者共发表20余篇分类学论著, 描述鉴定我国古生代昆虫共61种, 归属于9目(总目)。这些标本分布于西北、 西南、 华东等9省区, 其中石炭纪47种, 二叠纪14种。本文统计了我国已发现的古生代化石昆虫属种名录以及它们的分布和地质年代, 总结了国内古生代化石昆虫当前的研究状况和发展趋势, 并分析了研究中存在的问题。其中关于化石昆虫普遍存在的脉序差异问题需给予足够的重视, 高级阶元的建立应更加慎重。研究表明我国古生代昆虫已经高度分异, 古翅类、 新翅类均已出现, 且代表着有翅昆虫辐射演化的重要阶段。  相似文献   
94.
Fossil plants from the lower part of Xianshuihe Formation in the Lanzhou Basin, Gansu Province were studied. The flora contains 29 species, representing 20 genera and 12 families, which include Lauraceae ( Daphnogene ), Lardizabalaceae ( Akebia ), Berberidaceae ( Berberis ), Ulmaceae ( Planera, Ulmus, Zelkova ), Betulaceae ( Alnus, Carpinus ), Myricaceae( Myrica ), Salicaceae ( Populus, Salix), Myrsinaceae(Ardisia), Rosaceae ( Prunus, Sorbus, Sorbaria, Spiraea ), Leguminosae ( Gleditsia, Sophora), Anacardiaceae (Rhus), Caprifoliaceae(Viburnum). An analysis of the floristic elements and their foliar physiognomy shows that most members of the flora are deciduous broad-leaved trees or shrubs with a few evergreen shrubs. The most noteworthy species is Rhus turcomanica which was present in the Middle Eocene to Late Eocene of Central Asia (Kazakhstan, Turkmenistan). Generally, Rhus turcomanica occurred at the same beds as Palibinia, an extinct fossil plant whose presence indicates a subtropical dry climate. Another species, Sorbaria callicomifolia Kornilova was present from the Early Oligocene to Early Miocene of Central Asia (Kazakhstan and Turkmenistan). According to an analysis of spores and pollen, this flora contains over 20 species. It is predominated by the angiosperm pollen. There appeared Ephedripites and Nitrariadites which were important elements in the dry area. Ephedripites was found from the Upper Cretaceous to Early Tertiary. Nitrariadites occurred in the Late Miocene, whereas Rhus turcomanica and Sorbaria callicomifolia were both reported in the subtropical dry area from the Middle Eocene to Early Oligocene. The latest record of Rhus turcomanica is from the Middle Eocene to Early Oligocene of Central Asia. The presence of this element in the lower part of Xianshuihe Formation may indicate that itsage is the latest stage of the Early Oligocene.  相似文献   
95.
对人类进化全过程的思索   总被引:7,自引:2,他引:5  
吴汝康 《人类学学报》1995,14(4):285-296
本文从人类的诞生,人类发展过程的连续与间断,人类进化过程中体质发展的不平衡性和现代人的进化等4方面来论述人类进化的全过程.  相似文献   
96.
The family Hamamelidaceae is one of the core (or key) groups for studying the phylogeny of Hamamelids. It is an important taxon for the palaeobotanists and the botanists in discussing the origin and early evolution of the angiosperms owing to its strong differentiation of gross and pollen morphological characters. In this paper, the systematic position, modern distribution pattern and fossil history of the genera are analyzed, and the place and time of origin of the family are discussed according to the principle of the unity between the phylogeny and distribution of plants. The paper consists four parts.  相似文献   
97.
现代人起源问题的新争论   总被引:2,自引:1,他引:1       下载免费PDF全文
吴汝康 《人类学学报》1989,8(2):182-185
现代人在分类学上称为晚期智人。他们是怎样起源的?长期来有两种理论,一种叫直接演化说(Direct evolution hypothesis)或系统说,也叫多地区起源说。这种理论认为现代人是由当地的早期智人以至猿人演化而来的,各人种在很久以前即已分歧,各自平行发展,演化成现代人,但长时期来互相有基因的交流。例如欧洲的白种人是由当地的尼安德特人逐渐演变来的;亚洲的黄种人是由当地的早期智人和猿人演变来的。另一种理论叫入侵论(Invasion hypothesis),也叫迁徙说或代替说,这种理论认为欧洲是典型尼人的家乡, 而解剖结构上的现代人是在欧洲以外地区演化出来, 然后侵人欧洲的尼人区域, 消灭了土著的尼人而形成的;侵人亚洲的也一样, 形成现代的黄种人。这种单一地区起源说过去一般认为亚洲西部是现代人最早形成的地区, 近年来有人提出非洲南部才是现代人最早形成的地区, 然后迁徙到世界各地。  相似文献   
98.
杨正纯 《人类学学报》1990,9(3):282-282
1989年3月,笔者在昆明市近郊官渡区大板桥鸡街子山南坡发现了一处旧石器文化遗址。遗址埋于一个被堆积填满,洞顶塌陷遭到剥蚀的洞穴内,海拔1963米,高出当地河水面约8米。经试掘,地层层序清楚,文化层厚达2米以上,其中含有人类化石。脊椎动物化石、石制品和用火遗迹:烧骨、灰烬、炭屑、烧过的树籽等。初步工作表明,它是一处有丰富的文化遗存的石器制造场。  相似文献   
99.
100.
Microfossils which matchLactoris (Lactoridaceae) pollen more closely than those of any other living angiosperm occur in Campanian to Paleogene sediments around the margins of Australia. These are referred to the fossil genus Lactoripollenites (Zavada & Benson 1987). A species belonging to the same genus occurs in older (Turonian-Santonian) deposits off southern Africa but Australian specimens represent not only the most southern, but also the youngest known (Oligocene) records to date. Our data support suggestions that theLactoridaceae were widespread across the Southern Hemisphere during the Late Cretaceous (Lammers & al. 1986,Zavada & Benson 1987). An homology between gymnosperm sacci and the saccus-like structures found in Lactoripollenites and some specimens ofLactoris pollen is contested, as is the use of (anasulcate) apertures to support the primitive position of the family.  相似文献   
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