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1.
The British elms have historically proven to be recalcitrant taxonomically, with at least six different levels of treatment being applied. The taxonomic history of"the group and the nomenclature is outlined from the ancient authors up until the present day. This paper is the foundation for future articles in which a novel taxonomic treatment is introduced.  相似文献   

2.
Thirty sheets of Gramineae, recently found in the Real Colegio Alfonso XII of San Lorenzo de El Escorial, belong to Lagasca & Clemente's Ceres Hispanica herbarium. The main corpus of the Ceres Hispanica collection is kept in the Real Jardín Botánico de Madrid, and the missing sheets were reported as having disappeared in 1823. The importance of the rediscovered material is evaluated from the point of view of its historical relevance.  相似文献   

3.
Lectotypification of the following Linnaean names of the genus Cardamine L. (Cruciferae) is presented Cardamine asarifolia, C. graeca, C. petraea (|M= Cardaminopsis petraea), C. resedgolia (including designation of an epitype), C. trifolia and C. virginica. The lectotypes of the previously typified names of this genus and the protologues of these names are discussed. The probable typotype for the lectotype of C. azcana is identified and the need for the conservation of the type of C. chelidonia is noted.  相似文献   

4.
Lectotypification of the name Thymus serpyllum L. (Lamiaceae) is presented. The name is typified by a specimen from the Burser herbarium (UPS), the only one which corresponds well with the present concept of T serpyllum and undoubtedly represents original material.  相似文献   

5.
The productivity and biomass of pristine coral reef ecosystems is poorly understood, particularly in the Caribbean where communities have been impacted by overfishing and multiple other stressors over centuries. Using historical data on the spatial distribution and abundance of the extinct Caribbean monk seal (Monachus tropicalis), this study reconstructs the population size, structure and ecological role of this once common predator within coral reef communities, and provides evidence that historical reefs supported biomasses of fishes and invertebrates up to six times greater than those found on typical modern Caribbean reefs. An estimated 233,000-338,000 monk seals were distributed among 13 colonies across the Caribbean. The biomass of reef fishes and invertebrates required to support historical seal populations was 732-1018 gm(-2) of reefs, which exceeds that found on any Caribbean reef today and is comparable with those measured in remote Pacific reefs. Quantitative estimates of historically dense monk seal colonies and their consumption rates on pristine reefs provide concrete data on the magnitude of decline in animal biomass on Caribbean coral reefs. Realistic reconstruction of these past ecosystems is critical to understanding the profound and long-lasting effect of human hunting on the functioning of coral reef ecosystems.  相似文献   

6.
Abstract. The historical biogeography of sturgeons is explored using information from palaeogeography, palaeontology and phylogenetic interrelationships. The integration of information from these diverse sources indicates that sturgeons reached a wide Laurasian distribution in the Cretaceous and Tertiary by freshwater and coastal dispersal routes across land connections and along newly forming continental margins. The fossil record also suggests a considerable degree of morphological stasis and also supports an estuarine habit, and perhaps diadromy, as an old and conserved life history trait. While a ‘centre of origin’ for sturgeons remains elusive, phylogenetic relationships indicate that diversification appears to have been associated with fragmentation of biota, and of landmasses and basins, by late Tertiary geological and climatic phenomena, such as orogeny and unequal glaciation over North America, the desiccation of central Asia and alteration of its drainages, and the formation of discrete Ponto-Caspian basins by the fragmentation of the Paratethys. Amphi-oceanic distributions of certain species (Acipenser medirostris Ayres) and sister taxa (e.g. A. oxyrhynchus Mitchill and A. sturio L.) are explained by coastal dispersal and subsequent vicariance by geological (sea-floor spreading and development of new continental margins) and climatic (Pliocene cooling) changes during the Tertiary. An hypothesis is developed for the relationships of the North American sturgeons and their potential relationships with the Siberian sturgeon A. baeri. Late Tertiary climatic and geological phenomena are hypothesized as mediators of vicariance and subsequent diversification of these acipenserids. It appears that although acipenserids are a geologically old group, the historical biogeography of surviving lineages is best explained by more recent geological and climatic changes.  相似文献   

7.
8.
Changes in forest cover and draining of wetlands for agriculture appear to have caused changes in the aquatic ecosystem of the River Kyrönjoki by the 16th century. In the 19th century, a decline of salmonid fish populations was widely observed as a further sign of degradation. During the latter half of the present century intensified use of naturally acidic soils has resulted in increased acidic run-off. Deterioration of water quality has extended to the estuary, where it has caused large fish-kills and affected the reproductive success of coastal species. Degradation of the coastal ecosystem, first observed in the decline of salmonids and later as a more general decline of other coastal fish populations, can be linked to spatially restricted events. The loss of key river and estuarine habitats exerted an effect over the reproduction and abundance of species migrating throughout the system. This effect contributed to observed temporal and spatial discontinuities in the degradation history. Monitoring changes in critical habitats may prove to be an early indicator of changes in the health of estuarine and coastal aquatic ecosystems.  相似文献   

9.
Sarah White 《Dreaming》1999,9(1):11-21
This essay proposes that etymology, the study of word roots, presents analogies with dreamwork, although parallels between them must be carefully framed. Quoting Freud and the seventh century encyclopedist Isidore of Seville, weaknesses in their use of etymological arguments are identified. Theories forged from word origins should not blur distinctions between word and thing or force linguistic process into support of a preconceived theoretical project. To explore Freud's notion of contraries in words and dreams, examples are offered of single Indo-European word roots capable of engendering divergent or contradictory modern meanings, as well as examples of divergent or contradictory modern meanings for words that have two or more derivations, e.g., the English word dream and French rêve. Tracing a place-name (Campidoglio) in an actual dream demonstrates that etymology and dreamwork are both reconstructive processes that should avoid determinism, accept uncertainty, and respect complexity.  相似文献   

10.
The biogeographic regions reconsidered   总被引:10,自引:0,他引:10  
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11.
观察金粟兰属7种、4变种植物不定根的组织发育,发现本属大多数植物不定根具有典型的单子叶植物不定根的组织特征,特别是在同一条根中初生木质部的脊数可以随根的发育而增加。双子叶植物和单子叶植物根的组织学系统发育不仅在本属大多数种内不定根的个体发育中得以重演,而且在属内种间得以重演。  相似文献   

12.
Gymnocarpos has only about ten species distributed in the arid regions of Asia and Africa, but it exhibits a geographical disjunction between eastern Central Asia and western North Africa and Minor Asia. We sampled eight species of the genus and sequenced two chloroplast regions (rps16 and psbB–psbH), and the nuclear rDNA (ITS) to study the phylogeny and biogeography. The results of the phylogenetic analyses corroborated that Gymnocarpos is monophyletic, in the phylogenetic tree two well supported clades are recognized: clade 1 includes Gymnocarpos sclerocephalus and G. decandrus, mainly the North African group, whereas clade 2 comprises the remaining species, mainly in the Southern Arabian Peninsula. Molecular dating analysis revealed that the divergence age of Gymnocarpos was c. 31.33 Mya near the Eocene and Oligocene transition boundary, the initial diversification within Gymnocarpos dated to c. 6.69 Mya in the late Miocene, and the intraspecific diversification mostly occurred during the Quaternary climate oscillations. Ancestral area reconstruction suggested that the Southern Arabian Peninsula was the ancestral area for Gymnocarpos. Our conclusions revealed that the aridification since mid‐late Miocene significantly affected the diversification of the genus in these areas.  相似文献   

13.
目的探讨1950~2007年中国深部真菌病的历史地理学规律,为防治该类疾病提供相关理论依据。方法检索1950~2007年中国深部真菌病文献,设置发病年龄、病种、相关发病因素等特征变量,以中间年限1980年和中国八大地区为界,采用SPSS13.0对报道的15778例深部真菌病在不同时段及不同地区间的特征进行分析。结果中国深部真菌病呈逐年增长趋势,在地域上逐渐由集中向分散变化,报道病例数前三位的地区依次为长江中下游地区、中原地区和岭南地区。中国深部真菌病的高发年龄段、病种和相关发病因素具有不同的历史地理学特征,1950~2007年,该病的高发年龄均为中青年,但1980年后,中青年比例下降,儿童和老年病例增多;且报道病种在1980年后明显增多,其中以念珠菌病最多见和最广泛,而鼻孢子菌、球孢子菌、帚霉菌感染区域仍较局限;同时,1980年前外伤是发病主要相关因素,而在1980年后被不洁性接触、抗生素滥用、慢性病等取代。结论中国深部真菌病的发病率将逐年上升,气候湿润、经济发达、人口稠密的长江中下游和中原地区等将成为该类病的主要发病区。将深部真菌病的防治工作与其历史地理学特征结合起来,对从整体上把握该类疾病的发病特征和趋势具有重要意义。  相似文献   

14.
This paper provides a review of the current status and historical distribution of Lobotes surinamensis in the Mediterranean Sea. Thirty two records were compiled for the period between 1968 and 2016, which shows that the species is in the Mediterranean much more abundant than previously understood.  相似文献   

15.
Many attempts to understand the cultural impact of the forces of modernism, capitalism, and globalization have come to highlight contemporary cultural diversity at the expense of reifying a homogenized past of traditional, static societies. The "savage slot" still provides a convenient myth for characterizing small-scale communities before the advent of modernism—communities that experienced dramatic change only as they were pulled into the world system. Archaeological evidence from the southeastern United States challenges this stereotype, as Native American groups routinely migrated and continually redefined notions of "place" and "locality"—processes often treated as distinctly (post)modern. Such case studies emphasize the importance of working toward a deep historical anthropology that will continue to undermine stereotypes about the Other in the past as well as the present.  相似文献   

16.
稻属多倍体的研究历史及存在问题   总被引:1,自引:0,他引:1  
稻属Oryza隶属于禾本科Poaceae稻亚科Oryzoideae稻族Oryzeae, 包括20多个种, 其中近1/2的种类为异源多倍体植物。这些多倍体不但数量多而且涉及BC、CD、HJ和HK等多种染色体组构成, 广泛分布于热带亚洲、非洲、大洋洲和拉丁美洲。由于具有重要的经济和理论研究价值, 稻属植物一直在植物学研究中备受瞩目。相应地, 稻属多倍体植物的研究也积累了丰富的资料。本文通过回顾以往对稻属植物的研究历史, 特别关注有关多倍体的研究, 结合我们最近的研究总结了稻属多倍体分类和系统发育关系研究的最新进展, 同时对稻属多倍体研究中存在的问题及未来研究方向进行了讨论。  相似文献   

17.
以秀头叶蝉亚科昆虫在世界范围的地理分布为依据,结合其代表类群的系统关系及特有分布区的聚类分析结果,探讨了该亚科在不同分布区的分布格局、多样性水平、起源、演化和扩散轨迹。研究结果表明秀头叶蝉亚科主要局限分布于东洋区及古北区的地中海亚区,但向东南方向扩散至华莱士线及韦伯线以东的澳洲区北部。该亚科代表类群的系统发育关系及11个特有分布区的聚类关系表明,其各特有分布区可被分为4支,且该亚科的起源、演化、扩散与相关地区的大陆漂移、地质及气候演化历史密切相关;其中,中南半岛的分化程度(属级、种级水平)最高,应是该亚科的起源和分化中心。该亚科的分化、扩散轨迹主要呈现为2条:(1)新几内亚(或许(+澳大利亚))-加里曼丹-苏门答腊-马来半岛-中南半岛-中国中部、南部(+海南、台湾)-(中国西南部+尼泊尔+印度东北部)-(印度西北部+阿富汗东部);(2)中南半岛-中国中部、南部(+海南、台湾)-(西亚地区+地中海沿岸地区)。  相似文献   

18.
This article is not a survey of all the research made during the last half century at the ‘Laboratoire de Photosynthèse’ of the ‘Centre National de la Recherche Scientifique’ (CNRS) in Gif-sur-Yvette, but rather some personal recollections, as faithful as possible. Not all people could be mentioned and the scientists named here are mainly those who, at different stages of the laboratory's evolution, created their research teams, within or outside the laboratory. The laboratory, closed now as an administrative entity, was founded in 1953 by the CNRS in Gif-sur-Yvette, near Paris. Besides the emerging research groups in Paris and at Saclay, it was then the only one in France to be entirely dedicated to photosynthesis. Initially, the focus was on metabolic biochemistry of photosynthesis in whole plants and unicellular algae. In 1959, biophysics of primary and associated processes was added and in 1966, the laboratory was enlarged to include molecular genetics and, somewhat later, structural biology. Most of the early members of the laboratory have now gone offstage, but the research goes on, in Gif and elsewhere, thanks to the numerous high-level scientists that have been trained there. Most of the basic questions have now been answered, and interest has shifted in two directions, atomic and integrated, while many other facets of research are no longer specific to photosynthesis but part of more general biological problems, a normal situation for an area that has reached its maturity. This paper is dedicated to the scientists, technicians, students and visitors who could not all be cited here, but who contributed so much to the life of the laboratory. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

19.
Distribution of rotifers in African fresh and inland saline waters   总被引:2,自引:2,他引:0  
The distribution of rotifers in African fresh and inland saline waters is discussed in the light of historical expeditions and modern limnological research. Number of papers published and number of rotifer species described for each country are given. Some peculiarities of African rotifer fauna are described.  相似文献   

20.
We analysed patterns of animal dispersal, vicariance and diversification in the Holarctic based on complete phylogenies of 57 extant non‐marine taxa, together comprising 770 species, documenting biogeographic events from the Late Mesozoic to the present. Four major areas, each corresponding to a historically persistent landmass, were used in the analyses: eastern Nearctic (EN), western Nearctic (WN), eastern Palaeoarctic (EP) and western Palaeoarctic (WP). Parsimony‐based tree fitting showed that there is no significantly supported general area cladogram for the dataset. Yet, distributions are strongly phylogenetically conserved, as revealed by dispersal‐vicariance analysis (DIVA). DIVA‐based permutation tests were used to pinpoint phylogenetically determined biogeographic patterns. Consistent with expectations, continental dispersals (WP?EP and WN?EN) are significantly more common than palaeocontinental dispersals (WN?EP and EN?WP), which in turn are more common than disjunct dispersals (EN?EP and WN?WP). There is significant dispersal asymmetry both within the Nearctic (WN→EN more common than EN→WN) and the Palaeoarctic (EP→WP more common than WP→EP). Cross‐Beringian faunal connections have traditionally been emphasized but are not more important than cross‐Atlantic connections in our data set. To analyse changes over time, we sorted biogeographic events into four major time periods using fossil, biogeographic and molecular evidence combined with a ‘branching clock’. These analyses show that trans‐Atlantic distributions (EN‐WP) were common in the Early‐Mid Tertiary (70‐20 Myr), whereas trans‐Beringian distributions (WN‐EP) were rare in that period. Most EN‐EP disjunctions date back to the Early Tertiary (70‐45 Myr), suggesting that they resulted from division of cross‐Atlantic rather than cross‐Beringian distributions. Diversification in WN and WP increased in the Quaternary (< 3 Myr), whereas in EP and EN it decreased from a maximum in the Early‐Mid Tertiary.  相似文献   

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