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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Estrutura populacional intraespecífica e diversidade genética de Osteocephalus taurinus (Anura: Hylidae) no interflúvio Purus-Madeira, Amazônia Central

Yépez, Diego Armando Ortiz 23 May 2016 (has links)
Submitted by Inácio de Oliveira Lima Neto (inacio.neto@inpa.gov.br) on 2016-08-29T15:32:02Z No. of bitstreams: 2 Diego Armando Ortiz Yépez.pdf: 19833664 bytes, checksum: 980ab522bd39c3c2a7172f0bdf3013b1 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Inácio de Oliveira Lima Neto (inacio.neto@inpa.gov.br) on 2016-08-31T12:53:11Z (GMT) No. of bitstreams: 2 Diego Armando Ortiz Yépez.pdf: 19833664 bytes, checksum: 980ab522bd39c3c2a7172f0bdf3013b1 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Inácio de Oliveira Lima Neto (inacio.neto@inpa.gov.br) on 2016-08-31T12:56:53Z (GMT) No. of bitstreams: 2 Diego Armando Ortiz Yépez.pdf: 19833664 bytes, checksum: 980ab522bd39c3c2a7172f0bdf3013b1 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2016-08-31T12:58:23Z (GMT). No. of bitstreams: 2 Diego Armando Ortiz Yépez.pdf: 19833664 bytes, checksum: 980ab522bd39c3c2a7172f0bdf3013b1 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-05-23 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Fundação de Amparo à Pesquisa do Estado do Amazonas - FAPEAM / The Amazon rainforest is the most biodiverse biome in the world, where amphibians are one of the biological groups with the highest levels of cryptic diversity reported across taxa. Despite noticeable efforts, processes driving differentiation among populations and speciation remains largely unknown in this biome, especially based on dense sampling over refined scales. We studied the population structure and genetic diversity of the Manaus slender ledged tree frog, Osteocephalus taurinus, along a geographic gradient of approximately 900 km. Using molecular markers including mitochondrial and nuclear genes, and microsatellites, we estimate the phylogenetic relationships, population structure, and patterns of intraspecific genetic variation and geographic differentiation through the study area. Our data recovered six genetic groups: two corresponding to O. taurinus and O. oophagus from its type locality, Reserva Ducke, at northern of Amazonas River. The third group corresponds to an O. taurinus population isolated at right bank of upper Madeira River. However, evidence for restricted gene flow was detected along the upper Madeira River. Within Purus-Madeira interfluve, the remaining three O. taurinus populations replace each other latitudinally along geographical and environmental gradients, with two contact zones identified. One contact zone is concordant between mitochondrial and nuclear DNA and corresponds to an ecotone region between closed- open rainforests. Following the riverine barrier hypothesis, natural selection by means of genetic drift is expected to cause differentiation among populations by large Amazonian rivers as vicariant barriers. Within continuous forested regions, abrupt transitions on gene frequencies are suggestive of narrow contact or tension zones. In those areas, selection is expected to be favored by local adaptation to different environmental conditions, given selection against dispersing migrants from immediate but environmentally distinct regions and against hybrids. / A Amazônia é o bioma mais biodiverso da terra, e os anfíbios são um dos grupos com as maiores taxas de diversidade críptica registradas nessa região. No entanto, os mecanismos causantes de diferenciação entre populações e especiação mantem-se pouco conhecidos nesse bioma, especialmente com base em amostragens densas em escalas refinadas. Estudei a estrutura populacional e diversidade genética da rã hylídea Osteocephalus taurinus, ao longo de um gradiente geográfico de aproximadamente 900 km na Amazônia central, Brasil. Usando marcadores moleculares que incluíram DNA mitocondrial, nuclear e microssatélites, estudei as relações filogenéticas, estrutura populacional, e padrões de variação genética intraespecífica e diferenciação geográfica na área de estudo. Seis grupos genéticos foram recuperados pelas análises: dois correspondem ao O. taurinus e O. oophagus de sua localidade tipo, Reserva Ducke, ao norte do Rio Amazonas. O terceiro grupo corresponde a uma população de O. taurinus isolada na margem direita do Rio Madeira superior. No entanto, evidência de fluxo gênico restrito foi detectada no Rio Madeira superior. Dentro do interflúvio Purus-Madeira, as três populações de O. taurinus substituíram-se ao longo de gradientes geográficos e ambientais, com duas zonas de contato identificadas. Uma zona de contato é concordante entre o DNA mitocondrial e nuclear, e corresponde a uma região no ecótono entre as florestas fechadas e abertas. Segundo a hipótese de barreiras riverinas, espera-se que seleção natural causada por deriva gênica cause diferenciação entre populações separadas por grandes rios Amazônicos como barreiras vicariantes. Dentro de regiões contínuas de floresta, transições abruptas nas frequências gênicas sugerem zonas estreitas de contato ou tensão ecológica. Nessas áreas, espera-se que seleção seja favorecida por adaptação local às diferentes condições ambientais, por meio de seleção contra migrantes de outras regiões imediatas, mas ambientalmente distintas, e contra híbridos.
2

Predation, Palatability and the Distribution of Tadpoles in the Amazon Rainforest

Hero, Jean-Marc, n/a January 1991 (has links)
A variety of aquatic habitats with different levels of potential predators are available to larval amphibians in Central Amazon rainforest. The anuran community at Reserva Florestal Adolfo Ducke, 25 km east of Manaus, Amazonas, Brasil, was studied to determine which species have eggs and/or larvae in water and how those larvae are distributed in time and space. The temporal and spatial distribution of potential predators as well as abiotic characteristics of these waterbodies were determined simultaneously to test for correlations with the distribution of tadpoles. The distribution of tadpoles was strongly related to fish predation pressure. Several tadpole species were found only in waterbodies with high fish abundance and thus have the ability to survive with fish. Most of these tadpoles were found to be unpalatable in controlled experiments. Unpalatability is the major adaptation allowing the coexistence of tadpoles and fish and is thus a major factor affecting tadpole community composition in this system. Controlled experiments showed that fish do not eat anuran eggs while the tadpoles of Leptodacrylus knudseni and Osteocephalus taurinus ate all types of eggs offered. The percentage of anurans with aquatic oviposition was positively related to fish abundance and negatively related to the occurrence of species of tadpole that ate eggs in experiments. These findings suggest that the present patterns of anuran distribution represent an evolutionary response to predation on the eggs and larvae. Contrary to the models of Heyer et al. (1975) and Wilbur (1984), desiccation and predation-pressure were not the major factors affecting species richness within waterbodies of the RFAD rainforest. In support of the model of Heyer et al. (1975), anuran species richness was correlated with the size of the waterbody. This could be because the size of the waterbody is related to increased complexity and availability of microhabitats. The range of volumes of waterbodies was also found to directly affect species richness of the RFAD community. While predation appeared to have a limited effect on species richness of individual ponds, predation-pressure was found to have a major influence on species composition. Anuran eggs and larvae survived with specific predators by possessing particular survival-traits (e.g. unpalatability and oviposition strategies). However, survival-traits were not effective against all predators in all habitats. The distribution of different predators among ponds provides a patchy environment on a local scale (i.e. within ponds). When combined with the variety of survival-traits exhibited by the anuran species, this spatial patchiness in predation contributes towards species richness within the anuran community of the RFAD rainforest.
3

Variação geográfica de Osteocephalus taurinus Steindachner, 1862 (Amphibia : Anura : Hylidae)

ESTUPIÑÁN-TRISTANCHO, Ruth Amanda 06 1900 (has links)
Submitted by Edisangela Bastos (edisangela@ufpa.br) on 2013-08-02T20:56:19Z No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_VariacaoGeograficaOsteocephalus.pdf: 5143881 bytes, checksum: a70a57c92d7d8f6435a6707e91562106 (MD5) / Approved for entry into archive by Ana Rosa Silva(arosa@ufpa.br) on 2013-08-21T16:54:03Z (GMT) No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_VariacaoGeograficaOsteocephalus.pdf: 5143881 bytes, checksum: a70a57c92d7d8f6435a6707e91562106 (MD5) / Made available in DSpace on 2013-08-21T16:54:03Z (GMT). No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_VariacaoGeograficaOsteocephalus.pdf: 5143881 bytes, checksum: a70a57c92d7d8f6435a6707e91562106 (MD5) Previous issue date: 2001 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / MPEG - Museu Paraense Emílio Goeldi / Osteocephalus taurinus é uma espécie nominal de ampla distribuição na Amazônia e nos llanos do Orinoco. Sua grande variação morfológica indica que se trata de um complexo de espécies. O presente estudo examina a variação geográfica de vários caracteres morfológicos e morfométricos da espécie nominal, avalia a hipótese de tratar-se de fato um complexo de espécies; e testa a teoria da atual distribuição das formas, através de padrões biogeográficos, ecológicos e de regímen de precipitação já definidos. A partir de 431 espécimes estudados foram selecionadas 16 populações, nas quais foram analisados 20 caracteres anatômicos internos, 14 caracteres morfométricos e seis caracteres morfológicos externos. Através de análises estatística e mapas de isolinhas evidenciou-se que O. taurinus não se trata de um complexo de espécies e sim possui uma grande variação intra e interpopulacional das caraterísticas morfométricas e morfológicas. Simultaneamente, foram observados caracteres anatômicos internos polimórficos. O primeiro componente obtido através de uma análise de componentes principais mostra uma variação clinal do tamanho corporal ao longo da distribuição geográfica total, mais evidente nos machos. Em outros caracteres analisados, a variação fico independente do cline. O padrão espacial do tamanho indicou que as formas maiores ocorrem nas terras baixas da Amazônia, onde a vegetação de floresta ombrofila divide as áreas de cerrado ao norte e ao sul do continente sul americano. Nestas últimas áreas, ocorrem com maior intensidade as formas menores. Esta distribuição espacial não se explicou através das divisões propostas por outros autores para Amazônia, o que pode ser devido a um mascaramento gerado pela grande variação intrapopulacional. O modelo espacial do tamanho corporal de O. taurinus não corresponde a um padrão de isolamento por distância, o que pode sugerir que a colonização da espécie em algumas áreas seja recente. Este estudo confirma a hipótese da origem do gênero no início do Plioceno, o que indica que O. taurinus teria tido tempo suficiente para se dispersar antes do surgimento dos Andes como barreira geográfica. / Osteocephalus taurinus is an Amazonian and Orinochian nominal species with a wide geographic distribution. Its great morphologic variation has suggested that O. taurinus is in fact a species complex. This study examines the geographic variation of morphometric and morphologic characters. The species complex hypothesis is tested. Simultaneously, in order to explain the present body form distribution by biogeographic, rainfall and ecological patterns previously established for Amazonia, these patterns were assessed. From total 431 specimens studied, 16 populations were selected for analysis 20 of inner anatomic structures, 14 morphometric and 6 morphologic external characteres. Statistical analyses and isoline maps indicated that O. taurinus not is a especies complex and exist a interpopulation and intrapopulation variation on the morphometry and morphology of O. taurinus. Polymorphic anatomical characters ocurrs in this species. The first axis of a principal component analysis showed a clinal variation of body size along the entire geographic distribution was most plainly evident in males. Clinal variaton in other characters studied was independent of cline. Spatial size distribution indicated the largest specimens occur in the Amazon lands low, where rainforest vegetation divides savanna areas to the north and south of South America. These two last areas more often presented the smaller forms. In this study, the distribution observed for O. taurinus was not explained by traditional divisions of Amazonia, and suggest some noise generated by high intrapopulational variation. This spatial model of O. taurhius body size did not show a pattern of isolation by distance, which may suggest a recent arca colonization by this species. Simultaneusly, the study confirms the early Pliocenic origin hypothesis for Osteocephalus, which allowed O. taurinus had time to disperse before the Andes emerged as a geographical barrier.

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