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11.
The biology, ecology, biogeography, phylogeny, and evolution of sand-dwelling scorpions are reviewed. We present general features of sand that form the ecological theatre on which psammophiles have evolved. Sand scorpions, compared to those that live off sand, are not very diverse in any one local habitat, although they are often relatively abundant. Worldwide, they are represented by 29 genera, 11 of which exist exclusively in sand. Endemic genera belong to non-related families, suggesting that psammophilic adaptations evolvedin situin different sand deserts of the world.  相似文献   
12.
The Elk Butte Member of the Pierre Shale of southeast South Dakota and northeast Nebraska yields a late Maastrichtian cephalopod fauna of nautiloids, belemnites and ammonites of theFeletzkytes nebrascensisZone, best known from the near-shore facies of the Fox Hills Formation. ThenebrascensisZone is the highest distinct marine assemblage that can be recognised in the Western Interior, although ammonites occur as rarities high in the Lance Formation in Wyoming. Elements of the fauna occur in the Gulf Coast and Atlantic Seaboard, and extend into the highest Maastrichtian nannofossil Subzone CC26b, ofMicula prinsii, in Texas. These occurrences point to the existence of a southerly marine route for migration into and out of the northern Interior during the late late Maastrichtian. An analysis of Maastrichtian ammonite occurrences in West Greenland reveals no evidence for a marine link to the western Interior at this time, but rather indicates an open marine link to the North Atlantic region.The presence of upper upper Maastrichtian Pierre Shale in southeast South Dakota and northeast Nebraska, deposited in water depths that are conservatively estimated at 100-200 m, suggests that marine conditions (evidence for which has been removed by post-Cretceous erosion) may have extended well to the north of the shoreline position indicated in recent palaeogeographic reconstructions.  相似文献   
13.
From a trawling at 448–512 m in Palliser Bay, Cook Strait, New Zealand, molluscs associated with. Tertiary siltstone concretions and with a large colony of Goniocorella dumosa (Alcock) are listed. A juvenile Acesta, extremely tall and extremely broad forms of Emarginula striatula Quoy & Gaimard, and the animals of Stilifer neozelanica Dell and of Waipaoa marwicki Dell are described. Sculptifer, a new genus provisionally included in the Fossaridae, is proposed for Stilifer neozelanica. New species of Danilia and Pholadidea are described and their relationships discussed. Emarginula lophelia Beu, 1967 is synonymized with E. striatula Quoy & Gaimard, 1834, and the recent New Zealand forms of Emarginula are reviewed.  相似文献   
14.
中国植物地理学从20世纪20年代初创到当前繁荣经历了100年的发展,近30年来测序技术和生物信息技术的进步,促进了分类、进化和生态等学科交叉融合,中国植物地理学在诸多方面取得了突破性进展,主要包括:① 植物类群和区系在中国整体上按纬度、经度和海拔呈现出规律性;物种丰富度、系统发生多样性和特有性热点集中分布在南部山地,少数分布在北方山地和干旱地区。② 关于大尺度植物多样性格局及形成机制,多数热带起源科的物种多样性格局受冬季低温的限制,而多数温带起源科的物种多样性格局由末次冰期以来的气候变化主导;中国山地植物和群落具有显著的垂直地带性和空间分布异质性,热量因子是中国高山植物区系地理分异的首要气候因子。③ 中国大多数现生被子植物属(约66%)是在中新世及其以后分化;500 mm年等降水线是中国植物区系年龄和植被分区最重要的分界线;中国植物区系、区系中的特征或关键类群的起源和多样化与青藏高原抬升和亚洲季风加强密切相关。未来,时间和空间的结合仍是植物地理学研究的主旋律,类群、群落和区系分化时间的估算及物种分布数据的分辨率是研究者关注的焦点,植物大数据的持续积累和完善将为学科发展提供强大动力和广阔前景。  相似文献   
15.
Abstract

The agricultural system in West Pakistan is largely subsistence-oriented, and extensive areas are devoted to produce the low-value crops. Only a small portion of the total cropped area is used to raise cash crops. However, there are regional differences in cropland use in the province. The study focuses on regional variations in the cropping patterns in West Pakistan by establishing the crop combination areas. The crop combination areas also point out a land-use distinction between the areas. Also, the changes in some of the important crops in terms of their land occupancy in the area during the fifteen-year period have been analyzed.  相似文献   
16.
17.
Six major groups of trilobites from the Silurian and Devonian of Japan are evaluated for their paleobiogeographical signature. Silurian illaenids and scutelluids show four generic‐level and at least two species‐level links with the Australian segment of the Gondwana paleocontinent; encrinurids also indicate two generic‐level links with Australia and also the South China paleocontinent; whilst Devonian phacopids, and possibly proetids, suggest at least two generic‐level links with the North China paleocontinent. These different patterns may reflect the fragmentary biostratigraphical record of Japanese trilobites, but they also appear to reflect paleoenvironmental parameters associated with lithofacies, and paleoecology. Thus, Japanese assemblages of proetids and phacopids occurring in deep‐water clastic lithofacies have counterparts in similar settings in North China, and Japanese scutelluids and illaenids are strongly associated with shallow marine carbonate lithofacies that are similar to those of their occurrences in Australia. Japanese encrinurids occur in carbonate rocks indicative of shallow marine settings in the Kurosegawa Terrane, and they demonstrate a consistent paleobiogeographical affinity with Australia and South China. Larval ecology cannot be directly assessed for Japanese trilobite groups. However, proetids have consistently been shown to have planktonic protaspides, whereas illaenids, scutelluids, and encrinurids have benthic protaspides. Planktonic protaspides would have a greater propensity for distribution in ocean currents than benthic ones, and therefore may be of more limited paleobiogeographical utility. The combined data from the six different groups indicates that the complex paleobiogeographical patterns of the Japanese trilobite assemblages need to be interpreted with caution, and similarity of taxa does not necessarily denote paleogeographical proximity to other regions.  相似文献   
18.
The hypothesis that continental shelf ecosystems export a major fraction of the carbon produced by the phytoplankton during the spring bloom was tested during the Shelf Edge Exchange Processes (SEEP) experiment off the north-east coast of the United States in 1984. The total benthic standing stocks in terms of organic carbon (macrofauna, meiofauna and bacteria) have been estimated in the SEEP area. Their preponderance on the continental shelf was partial evidence that little organic matter escapes to the upper continental slope. Measurements of the metabolism of the biota allowed calculation of turnover times of organic detritus and the total biota. The turnover time of detritus increased as grain size decreased, suggesting that fine-grained deposits contain mostly refractory, non-reactive compounds, especially on the deep slope. Turnover times of the total biota were about the same in the coarse- as in the fine-grained shelf deposits, but a far larger fraction of the turnover was attributed to the bacteria in the fine sediments. On average, about 25 per cent of the primary production appeared to be utilized by the aerobic benthos on the continental shelf in the SEEP area. The role of anaerobes at depth in the sediments remains uncertain. This study, along with a review of other recent work, leads to the conclusion that only a small fraction of continental shelf phytodetritus is exported across a distinct shelf-slope hydrographic frontal system. What is not consumed in the spring is utilized on the shelf during the ensuing stratified season. More open ended ecosystems may export production more readily.  相似文献   
19.
《自然地理学》2013,34(3):261-275
Biogeographers choose to align their scholarship within different domains, from ecological or historical biogeography, to landscape ecology, macroecology, or the analytical perspective initiated with the theory of island biogeography. Biogeography is also practiced under the umbrella of geography, as geographical biogeography. Using the ISI Web of Science journal article database, I performed content visualizations of research authored by those biogeographers with an identity or interest aligned with geography. Content affinities with ecological biogeography were strong. However, physical geography materialized as the core of biogeographical inquiry for geographers based upon the central location of physical geography within these visualizations, and upon the ranking of journals where these geographers publish. I argue that the systems legacy of physical geography provides geographical biogeographers with an identity and an invitation to connect with the field of scholars advancing the study of complex systems.  相似文献   
20.
全球前寒武纪基底构造格局与古大陆再造问题   总被引:17,自引:1,他引:16  
王鸿祯  张世红 《地球科学》2002,27(5):467-481
全球前寒武纪基底构造格架与构造单元的划分是古大陆再造和泛大陆拼合的重要基础.本文整理了基底构造单元的级别体系, 以晋宁期和印支期为准, 提出了一级构造域、二级陆台及地区和三级陆核、地块等3级划分.分出了5个一级、14个二级和若干个三级单元, 并予以系统编号, 以便查询和增修.认为超大陆是泛大陆的组成部分, 现在重点研究的罗迪尼亚超大陆已经涉及全球, 进入了泛大陆-850的研究范围.论证了中国3个陆台和华夏地区在新元古代晋宁期的位置关系, 认为它们相距不远, 并部分相互碰撞, 构成亚洲中轴(大华夏)构造域.讨论了罗迪尼亚的流行模式及SWEAT连接问题.指出新元古代Chuaria Tawuia宏观藻组合在东亚和北美西部的分布, 认为大华夏构造域应作为一个松散的整体与劳伦古大陆相邻, 并概略讨论了泛大陆-850的再造格局特征.提出了经过改进的泛大陆-250在中二叠世(280257 Ma)的再造模式, 讨论了古植物和海生动物生物地理分区在古大陆再造中的意义.   相似文献   
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