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1.
《Comptes Rendus Palevol》2002,1(6):313-323
Numerous fields of Life and Earth Sciences as well as Human Sciences are indebted to Alcide d’Orbigny for his huge and innovating work. From his long journey in South America, he brought back a rich wealth of scientific collections and information related to Botany, Zoology, physical and human Geography, Geology, and Ethnography. Founder of Micropalaeontology, by his foraminiferal studies, and of Biostratigraphy, he is still present in Sciences today thanks to the numerous implications of his works in numerous domains of both academic research and economic sector.  相似文献   

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3.
This article traces the life and work of Marquis Robert de Wavrin de Villers au Tertre (1888–1971), a Belgian explorer and ethnographer. While fragments of his oeuvre are familiar to scholars of South America, he is almost completely unknown in historical studies, and largely forgotten within anthropology too. Here we will explore his filmic work as well as its contribution to the history of visual anthropology. While de Wavrin’s work cannot be divorced from the discipline’s colonial and Eurocentric heritage, we show that his visual record provides notable historic insights and merits further scholarly attention.  相似文献   

4.
Pachysandra is an eastern Asian-North American disjtunct genus with three species, two in eastern Asia (Pachysandra axillaris and Pachysandra terminalis) and one in eastern North America (Pachysandra procurnbens). Although morphological and cytological studies suggest a close affinity of Pprocumbens with P axillaris, molecular data from nuclear and chloroplast DNA regions have provided conflicting signals. In this study, we tested previous phylogenetic hypotheses using sequences of nuclear ribosomal DNA internal transcribed spacers and chloroplast ndhF gene from multiple individuals of each of the three species. We also estimated the time of divergence between eastem Asia and eastern North America. Our results support the morphological and cytological conclusion that P procumbens is more closely related to P axillaris than to P terminalis. The estimated time of divergence of P axillaris and P procumbens was 14.6±5.5 mya, consistent with estimates from many other eastern Asian-North American disjunct genera. The migration of Pachysandra populations from eastern Asia to North America might have occurred by way of the North Atlantic land bridge.  相似文献   

5.
Littorella (Plantaginaceae) is a disjunct, amphibious genus represented by three closely related species. Littorella uniflora occurs in Europe including Iceland and the Azores, L. americana is found in temperate North America, and L. australis grows in temperate South America. Littorella has been recognized in numerous floristic treatments, but its status as a genus has recently been questioned. Rahn (Botanical Journal of the Linnean Society 120: 145-198, 1996) proposed a new phylogeny for Plantaginaceae based on morphological, embryological, and chemical data in which he reduced Littorella to a subgenus of Plantago. This article compares the phylogeny proposed by Rahn to one based on DNA sequence data from the internal transcribed spacer (ITS) region. In our analysis, Littorella forms a strongly supported monophyletic clade sister to Plantago and its recognition at the generic rank appears warranted. Littorella australis is sister to L. americana, and this clade is sister to the European L. uniflora. This more distant relationship between L. uniflora and L. americana provides support for maintaining both taxa at the specific rank and suggests a European origin for Littorella. Our studies also indicate that the monotypic genus Bougueria is deeply nested within Plantago and that its inclusion within Plantago as proposed by Rahn appears justified.  相似文献   

6.
苏皖地区早志留世坟头组腹足类   总被引:4,自引:0,他引:4  
席与华 《古生物学报》1997,36(2):238-244
记述苏皖地区坟头组腹足类11属12种,其中Umbonellina cf.globulosa Yu,Raphistomina rhombistoma Yu,Trochonema cf.fragile Ulrich et Scofield常见于西南地区早志留世秀山组、上翁项群及石牛栏组。坟头组上段所产的三叶虫Coroncephalus,Kailia;头足类Sichuanoceras;腕足类Salopi  相似文献   

7.
In 1938 an expedition went from Great Britain to collect tuber-forming species of Solanum from mountainous areas of south and central America, a region generally regarded as the cradle of potato species. The plants brought back by the expedition form the core of the Commonwealth Potato Collection, which has since been added to from various sources. In 1941 Dr Ellenby began screening the various species and varieties in the Collection for resistance to eelworm. Quite soon he was able to demonstrate resistance in S. ballsii (now known as vernei. ) Later, after much labour and many disappointments, he also found evidence of resistance in a few lines of S. andigenum.  相似文献   

8.
I G Levy  N A Iscoe  L H Klotz 《CMAJ》1998,159(5):509-513
A 70-year-old woman who experienced a long period of depression after her first husband''s death from prostate cancer at the age of 63 has become increasingly anxious about her own health and that of her close family. A few years ago she married a man her own age; he is in good physical condition. Last year the family spent much of the winter in Florida, where the woman noticed several studies in the media suggesting that an epidemic of prostate cancer is occurring in North America and that because early detection can save lives men of retirement age should be checked by their physicians as soon as possible. In addition, 2 close friends recently diagnosed with prostate cancer. On his latest fishing trip her husband learned from a friend that 1 in 8 men get prostate cancer. He has not seen his family physician for several years, but his wife has booked an appointment for them to discuss their concerns.  相似文献   

9.
The colonization of America by Drosophila subobscura has been a unique exper iment in nature that has allowed us to explore the effects of evolution on a continental scale. To analyze this evolutionary event, nucleotide sequences of the Odh (Octanol dehydrogenase) gene were obtained for 43 lethal chromosomal lines from colonizing populations of North America and 5 from South America, in addition to 5 chromosomal lines from Europe with different viabilities and 2 from laboratory marker stocks. Since 10 different Odh haplotypes were found in America, the minimum number of colonizers would be 5 (or 3 mated females). Only one Odh haplotype was found in American O(5) inversions confirming that only one copy of this inversion was included among the sample of colonizers. The same Odh haplotypes were detected in association with the same chromosomal arrangements and with identical lethal genes in both North and South America indicating that exactly the same chromosome types reached both hemispheres. These observations indicate that the two continental colonizations are not independent. They are derived from the same colonization event. The population from which the colonization started should contain the O(5) inversion, a non-negligible frequency of the O(3+4+7) arrangement and all other arrangements found in America. So far the only populations that fulfill all these requirements are those from Greece, indicating that these populations can be considered good candidates as a starting point for an in depth analysis of the origin of the American colonization by D. subobscura.  相似文献   

10.
Exotic forest insects and their symbionts pose an increasing threat to forest health. This is apparently true for the red turpentine beetle (Dendroctonus valens), which was unintentionally introduced to China, where the beetle has killed millions of healthy native pine trees. Previous population genetics studies that used cytochrome oxidase I as a marker concluded that the source of D. valens in China was western North America. In contrast, surveys of fungi associated with D. valens demonstrated that more fungal species are shared between China and eastern North America than between China and western North America, suggesting that the source population of D. valens could be eastern North America. In this study, we used microsatellite markers to determine population structure of D. valens in North America as well as the source population of the beetle in China. The analyses revealed that four genetically distinct populations (herein named the West, Central, Northeast and Mexico) represent the native range of D. valens. Clustering analyses and a simulation‐based approximate Bayesian computation (ABC) approach supported the hypothesis that western North America is the source of the invasive D. valens population. This study provides a demonstration of non‐congruence between patterns inferred by studies on population genetics and symbiont assemblages in an invasive bark beetle.  相似文献   

11.
Synopsis Bill Ricker’s career went through many twists in his academic years. He had taken botany in his senior matriculation year at high school and he had collected over 100 species of flora before commencement of university life. At the conclusion of his first university year, he set out over the summer to collect a much larger sample of species, primarily from the Great Lakes-St. Lawrence ecoregion, to fulfil a requirement for a second year botany course (spermatophytes). He identified about 390 species, and some 254 were collected and pooled with those from previous years to make a final submission of 354 spermatophyte species. Field plant identification continued in each academic year thereafter, in concert with collections and identifications of aquatic invertebrates in his summer projects while under the employment of the Ontario Fisheries Research Laboratory. At the conclusion of his undergraduate years, Bill had taken more courses in botany than in zoology, and it was the summer employment that had really prepared him for postgraduate work in fisheries biology, which was ecologically oriented. When Bill left Ontario in the autumn of 1931 he had identified over 600 species of plants, excluding lower cryptogams, but including many aquatic species of higher plants. In western North America Bill’s botanical career began at Cultus Lake in 1931. He again studied all aspects of the basin while employed with the federal government, and from the work he assembled a Ph.D. thesis. At the time of thesis completion he had identified over 300 species of flora, including alpine plants at timberline, 1500 – 1800 m above lake level, and planktonic algae in its water column. In 1939, after more field fisheries work in the Fraser River basin of British Columbia, Bill accepted a position with the biological staff at Indiana University. In this period which concluded in 1950 he identified another 50 – 110 species of flora, all in the Carolinian ecoregion, and hitherto not seen by him. Considering all floral classes, Bill’s eastern North American repertoire had by then added up to 791 species, representative of more than 112 families of plants. Returning west for the remainder of his life, new identifications elsewhere added to his Cultus Lake list which slowly added up to about 1000 species for the west coastal region of North America. Flora was also identified elsewhere in the mid-continental region of North America, in Eurasia where the Abisko region of Lappland was a highlight, and in South America and New Zealand. Records of his botanical prowess, were kept primarily in his diaries, which began in 1923 and were maintained consistently to the end of 1934, and thereafter intermittently to 1949. The diaries reveal that his career as a budding botanist was subtly hijacked by a wily Professor W.H.K. Harkness in the rival Biology Department who out-manoeuvred Drs. R.B. Thompson and R.A. Sifton in the Botany Department. The former always managed to employ Bill in summer and keep him occupied in the department’s labs during the autumn and winter and spring, tying up any free time when the botanist had approached him on lab work. Certainly, the botany courses taken and which he excelled at were more appropriate for his aquatic ecological pursuits. Salesmanship won the day for the zoologists, but Bill was a life-long botanist regardless of whatever else he studied or managed throughout his professional career. The last days of his life had a botanical conclusion.  相似文献   

12.
This paper documents the history of the introduction of the soybean (Glycine max), a domesticate of China, to North America. Henry Yonge, the Surveyor-General of Georgia, planted soybeans on his farm at the request of Samuel Bowen in 1765. Mr. Bowen, a former seaman employed by the East India Company, brought soybeans to Savannah, Georgia, from China via London. From 1766, Mr. Bowen planted soybeans on his plantation “Greenwich” located at Thunderbolt, Georgia. The soybeans were used to manufacture soy sauce and vermicelli (soybean noodles). In addition, he manufactured a sago powder substitute made from sweet potatoes. The 3 products were then exported to England. Samuel Bowen received a patent for his manufacturing inventions for producing these products. Another early introduction of soybeans to North America was by Benjamin Franklin. In 1770 he sent seeds from London to John Bartram in Philadelphia.  相似文献   

13.
Joseph Hooker was one of the most widely travelled botanists of the Victorian period, having explored regions as far afield as Antarctica, Morocco and North America, though it is for his pioneering exploration of the Sikkim Himalaya that he is perhaps best remembered. Seamus O'Brien led four expeditions to this remote corner of the eastern Himalaya, and the results of these trips will appear in a new biography due to be published by Kew in 2018. He summarises that story here.  相似文献   

14.

The use of nuclear analytical techniques for environmental studies in South America is selectively reviewed since the time of earlier works of Lattes with cosmic rays until the recent applications of the PIXE (particle-induced X-ray emission) technique to study air pollution problems in large cities, such as São Paulo and Rio de Janeiro. The studies on natural radioactivity and fallout from nuclear weapons in South America are briefly examined.

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15.
The boreotropics hypothesis postulates a preferential tropical biotic interchange between North America and Eurasia during the early Tertiary that was directed by Eocene thermal maxima and the close proximity of these two continental plates. This preferential interchange occurred at a time when South America was geologically and biotically isolated. A prediction of this hypothesis posits that a taxon with a present-day center of diversity in tropical North America, and with an early Tertiary fossil record from any region there, has a high probability of having sister-group relatives in the Paleotropics and derived relatives in South America. We propose a test of this prediction with phylogenetic studies of two pantropical taxa of Leguminosae that have early Tertiary North American fossil records. Our findings are consistent with the boreotropics hypothesis, and additional evidence suggests that many tropical elements in North America could be descendants of northern tropical progenitors. Ramifications of this hypothesis include the importance of integrating the fossil record with cladistic biogeographic studies, theoretical bases for recognizing tropical taxa with such disjunct distributions as Mexico and Madagascar, identification of taxa that may be most useful for testing vicariance models of Caribbean biogeography, and integrating the study of disjunct distributions in temperate regions of the northern hemisphere with those in the neo- and paleotropics.  相似文献   

16.
Traditional concepts of the Bering Land Bridge as a zone of predominantly eastward expansion from Eurasia and a staging area for subsequent colonization of lower latitudes in North America led to early inferences regarding biogeographic histories of North American faunas, many of which remain untested. Here we apply a host-parasite comparative phylogeographical (HPCP) approach to evaluate one such history, by testing competing biogeographic hypotheses for five lineages of host-specific parasites shared by the collared pika (Ochotona collaris) and American pika (Ochotona princeps) of North America. We determine whether the southern host species (O. princeps) was descended from a northern ancestor or vice versa. Three parasite phylogenies revealed patterns consistent with the hypothesis of a southern origin, which is corroborated by four additional parasite lineages restricted to O. princeps. This finding reverses the traditional narrative for the origins of North American pikas and highlights the role of dispersal from temperate North America into Beringia in structuring northern diversity considerably prior to the Holocene. By evaluating multiple parasite lineages simultaneously, the study demonstrates the power of HPCP for resolving complex biogeographic histories that are not revealed by characteristics of the host alone.  相似文献   

17.
The status of Littorina littorea as an exotic species in North America has been debated in the biological literature for over a century. In recent decades, molecular data have been used to supplement historical and archaeological evidence that has suggested that the snail may have persisted in North America well before European settlers arrived. However, these earlier molecular studies have since been questioned due to incomplete sampling of both the geographical range of L. littorea and the genome of the species itself. Here we consider an amplified fragment length polymorphism screen of the nuclear genome, which provides a large number of independent dominant markers that can be used in resolving this historical puzzle. Although these data appear to refute earlier allozyme studies of L. littorea as indicating long-term divergence between European and American populations, the data are also problematic in that they include clear artefacts. We discuss these artefacts and suggest future approaches to definitively resolving the debate over L. littorea's introduction to North America.  相似文献   

18.
Separated throughout most of the Cenozoic era, North and South America were joined during the mid‐Pliocene when the uplift of Panama formed a land bridge between these two continents. The fossil record indicates that this connection allowed an unprecedented degree of inter‐continental exchange to occur between unique, previously isolated biotic assemblages, a phenomenon now recognized as the “Great American Biotic Interchange”. However, a relatively poor avian fossil record has prevented our understanding the role of the land bridge in shaping New World avian communities. To address the question of avian participation in the GABI, we compiled 64 avian phylogenetic studies and applied a relaxed molecular clock to estimate the timing of trans‐isthmus diversification events. Here, we show that a significant pulse of avian interchange occurred in concert with the isthmus uplift. The avian exchange was temporally consistent with the well understood mammalian interchange, despite the presumed greater vagility of birds. Birds inhabiting a variety of habitats and elevational zones responded to the newly available corridor. Within the tropics, exchange was equal in both directions although between extratropical and tropical regions it was not. Avian lineages with Nearctic origins have repeatedly invaded the tropics and radiated throughout South America; whereas, lineages with South American tropical origins remain largely restricted to the confines of the Neotropical region. This previously unrecognized pattern of asymmetric niche conservatism may represent an important and underappreciated contributor to the latitude diversity gradient.  相似文献   

19.
We have developed and characterized 13 microsatellite loci from a group of Anodonta species in western North America, and demonstrated their utility in populations representing two major clades in this genus. Allelic diversity and polymorphic information content were high for all loci, although these characteristics varied across populations. Deviations from Hardy-Weinberg genotypic ratios were not detected, although the estimated frequency of null alleles was high in one population for one locus. This is the first set of microsatellite loci to be developed for freshwater mussels in western North America, and will be useful for describing gene flow patterns among populations.  相似文献   

20.
To better understand the evolutionary history of the genus Centaurium and its relationship to other genera of the subtribe Chironiinae (Gentianaceae: Chironieae), molecular analyses were performed using 80 nuclear ribosomal ITS and 76 chloroplast trnLF (both the trnL UAA intron and the trnL-F spacer) sequences. In addition, morphological, palynological, and phytochemical characters were included to a combined data matrix to detect possible non-molecular synapomorphies. Phylogenetic reconstructions support the monophyly of the Chironiinae and an age estimate of ca. 22 million years for the subtribe. Conversely, both molecular data sets reveal a polyphyletic Centaurium, with four well-supported main clades hereafter treated as separate genera. The primarily Mediterranean Centaurium s.s. is closely related to southern African endemics Chironia and Orphium, and to the Chilean species Centaurium cachanlahuen. The resurrected Mexican and Central American genus Gyrandra is closely related to Sabatia (from eastern North America). Lastly, the monospecific genus Exaculum (Mediterranean) forms a monophyletic group together with the two new genera: Schenkia (Mediterranean and Australian species) and Zeltnera (all other indigenous American centauries). Several biogeographical patterns can be inferred for this group, supporting a Mediterranean origin followed by dispersals to (1) North America, Central America, and South America, (2) southern Africa (including the Cape region), and (3) Australia and Pacific Islands.  相似文献   

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