52 research outputs found

    Die Stoffwechselwirkungen der SchilddrĂŒsenhormone

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    Bird-termite interactions in Brazil: A review with perspectives for future studies

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    CiĂȘncia nĂŽmade: o IHGB e as viagens cientĂ­ficas no Brasil imperial

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    The Lauraceous Collections of Carl Friedrich Philipp Von Martius in the Flora brasiliensis

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    Genetic structuring in a Neotropical palm analyzed through an Andean orogenesis‐scenario

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    International audienceAndean orogenesis has driven the development of very high plant diversity in the Neotropics through its impact on landscape evolution and climate. The analysis of the intraspecific patterns of genetic structure in plants would permit inferring the effects of Andean uplift on the evolution and diversification of Neotropical flora. In this study, using microsatellite markers and Bayesian clustering analyses, we report the presence of four genetic clusters for the palm Oenocarpus bataua var. bataua which are located within four biogeographic regions in northwestern South America : (a) ChocĂł rain forest, (b) Amotape-Huancabamba Zone, (c) northwestern Amazonian rain forest, and (d) southwestern Amazonian rain forest. We hypothesize that these clusters developed following three genetic diversification events mainly promoted byAndean orogenic events. Additionally, the distinct current climate dynamics among northwestern and southwestern Amazonia may maintain the genetic diversification detected in the western Amazon basin. Genetic exchange was identified betweenthe clusters, including across the Andes region, discarding the possibility of any cluster to diversify as a distinct intraspecific variety. We identified a hot spot of geneticdiversity in the northern Peruvian Amazon around the locality of Iquitos. We alsodetected a decrease in diversity with distance from this area in westward and southward directionwithin theAmazon basin and the easternAndean foothills.Additionally,we confirmed the existence and divergence of O. bataua var. bataua from var. oligocarpus in northern South America, possibly expanding the distributional range of thelatter variety beyond eastern Venezuela, to the central and eastern Andean cordilleras of Colombia. Based on our results, we suggest that Andean orogenesis is themain driver of genetic structuring and diversification in O. bataua within northwestern South America

    Naturalistas viajantes Travel naturalists

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    O naturalista viajante Ă© aquele que nos sĂ©culos XVIII e XIX dedicava-se ao estudo da histĂłria natural, ou seja, da natureza, compreendendo os astros, o ar, os animais, os vegetais e minerais da superfĂ­cie e da profundidade da terra. Enquanto os naturalistas-viajantes do perĂ­odo colonial eram exclusivamente sĂșditos da Coroa portuguesa, encarregados de revelar as riquezas e utilidade dos recursos naturais, os que percorreram o Brasil no sĂ©culo XIX, apĂłs 1808, vinham de diversas regiĂ”es da Europa e estavam empenhados na observação e classificação dos homens e de suas lĂ­nguas considerados entre as espĂ©cies da natureza. Ligados Ă  nobreza ou a sociedades cientĂ­ficas, percorriam o solo brasileiro num esforço conjunto e planejado de revelar, colecionar e classificar os reinos naturais da AmĂ©rica.<br>During the XVIIIth and XIXth centuries, travelers that studied natural history were referred to as travel naturalists. Nature included the stars and planets, the atmosphere, flora and fauna, and surface and underground minerals. While in colonial times they were limited to citizens of Portugal who were instructed to discover natural resources and their uses, those who traveled through Brazil after 1808 came from different regions of Europe and were concerned with observing and classifying people and natural specimens found along the way. Sponsored by either noblemen or scientific societies, they traveled around Brazil in a combined endeavor of discovering, collecting, and classifying natural specimens on the American continent
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