Thiago Zahn - Academia.edu (original) (raw)

Papers by Thiago Zahn

Joint Conference on Language Evolution, 2022

One exciting but often puzzling aspect of the field of Language Evolution is the variety of theor... more One exciting but often puzzling aspect of the field of Language Evolution is the variety of theories and approaches it includes, sometimes with contradictory assumptions or pursuing different questions. It has been argued before that this variety arises in part from different theories of language. I argue that another important factor underlying disparate, sometimes incommensurate approaches are different understandings and definitions of 'evolution', including 'what counts as evolution' and 'what evolution can explain', and suggest that greater attention to discussions about evolution in the philosophy of biology may help untangle differences and similarities between approaches and foster constructive discussions between them.

A integração morfológica determina a quantidade de variação disponível em diferentes direções do ... more A integração morfológica determina a quantidade de variação disponível em diferentes direções do espaço multivariado entre um conjunto de caracteres, e pode assim ter importantes consequências evolutivas, enviesando a direção e a taxa de evolução morfológica em determinadas direções. Assim, estudar a evolução da integração morfológica é importante para entender a evolução fenotípica de uma linhagem. Neste trabalho, utilizo abordagens de genética quantitativa comparativa para estudar a evolução da integração morfológica no crânio em carnívoros da subordem Feliformia, grupo com extensa diversidade filogenética, morfológica e ecológica para o qual análises anteriores de integração analisaram número reduzido de espécies. Para este fim, comparo matrizes de covariância fenotípicas intra-populacionais quantificando a associação entre 35 distâncias lineares no crânio de um conjunto de táxons incluindo todas as sete famílias e mais de um terço da diversidade filogenética atual da subordem. I...

Full Random Skewers table of pairwise comparisons.Values below the diagonal are observed values a... more Full Random Skewers table of pairwise comparisons.Values below the diagonal are observed values and the ones above the diagonal are corrected values. The diagonal contain the matrix repeatabilities

Linear Discriminant Scores for the averages phenotypes for each taxa. LDA scores were used to cal... more Linear Discriminant Scores for the averages phenotypes for each taxa. LDA scores were used to calculate mahalanobis distances and were used as input in comparative analyses

Carnivora Cladogram used in analyses. Three in Newick format with no branch-lengths

Align cytochrome b sequences used to estimate branch-lengths

Individual species phenotypic covariance matrices. Zip file containing 145 CSV format-tables

Morphological integration refers to the fact that different phenotypic traits of organisms are no... more Morphological integration refers to the fact that different phenotypic traits of organisms are not fully independent from each other, and tend to covary to different degrees. The covariation among traits is thought to reflect properties of the species' genetic architecture and thus can have an impact on evolutionary responses. Furthermore, if morphological integration changes along the history of a group, inferences of past selection regimes might be problematic. Here we evaluated the stability and evolution of the morphological integration of skull traits in Carnivora by using evolutionary simulations and phylogenetic comparative methods. Our results show that carnivoran species are able to respond to natural selection in a very similar way. Our comparative analyses show that the phylogenetic signal for pattern of integration is lower than that observed for morphology (trait averages), and that integration was stable throughout the evolution of the group. That notwithstanding, Canidae differed from other families by having higher integration, evolvability, flexibility and allometric coefficients on the facial region. These changes might have allowed canids to rapidly adapt to different food sources, helping to explain not only the phenotypic diversification of the family, but also why humans were able to generate such a great diversity of dog breeds through artificial selection

Brazilian journal of biology = Revista brasleira de biologia, Jan 10, 2015

Brazilian Journal of Veterinary Research and Animal Science, 2018

Brazilian Journal of Veterinary Research and Animal Science

This study reports the factors which led a gated community located in Bragança Paulista (SP, Braz... more This study reports the factors which led a gated community located in Bragança Paulista (SP, Brazil), a non-endemic area for Brazilian Spotted Fever (BSF), to be classified as a Risk Area for transmission of this disease, showing that an increasing resident population of capybaras (Hydrochoerus hydrochaeris) in the area was likely responsible for a proliferation of Amblyomma sculptum ticks and acted as an amplifying host for Rickettsia rickettsii, the main etiologic agent of BSF. We report management actions proposed to control the local tick burden and reduce BSF risk, including measures to control parasitic and free-living tick populations and exclusion of the resident capybara population. Analyses of tick population data and R. rickettsii serology tests indicate that these measures were effective, greatly reducing the environmental burden of Amblyomma sculptum ticks and reducing the BSF transmission risk at the area.

Há um enorme número de pessoas a quem devo agradecer pela ajuda e companhia antes e durante este ... more Há um enorme número de pessoas a quem devo agradecer pela ajuda e companhia antes e durante este trabalho. Como é possível e provável que eu acabe esquecendo parte delas, começo com um agradecimento e um pedido de desculpas a essas. Continuo então com os lembrados diretamente. Ao Prof. Dr. Gabriel Marroig, meu agradecimento pela possibilidade de fazer este mestrado depois de me ausentar da academia por alguns anos, recebendo-me como orientador junto a uma equipe fantástica e me dando a oportunidade de seguir trabalhando com carnívoros, grupo de meu interesse já há tempos. À Dra. Erika Hingst-Zaher, por me introduzir ao estudo dos carnívoros e à morfometria na iniciação científica e pelo apoio e amizade em vários momentos posteriores. À Prof. Dra. Denise Scheepmaker e ao Prof. Dr. Rui Murrieta, por expandirem minha compreensão sobre evolução e sobre ciência como um todo. Ao Fábio Machado (Lugar) e ao Guilherme Garcia (Pato), amigos de longa data e colegas de laboratório desde os tempos da IC, pelas inúmeras discussões, conversas, críticas e ideias (por vezes a um mar de distância), pelo grande apoio e pela companhia em vários momentos. Eu talvez não chegasse ao final sem vocês. À Anna Penna (Papete), companheira de mestrado, pelas conversas e companhia em vários momentos ao longo dos tempos de vida cigana. E aos demais colegas do LEM durante este mestrado-Ogro, Alex, Monique, Tafinha, Dani, Paulinha e Aninha, pelas risadas durante estes anos e pelas diversas conversas, dicas e contribuições sobre diversos aspectos do trabalho-dos teóricos aos burocráticos.

Evolution; international journal of organic evolution, Jan 26, 2018

Morphological integration refers to the fact that different phenotypic traits of organisms are no... more Morphological integration refers to the fact that different phenotypic traits of organisms are not fully independent from each other, and tend to covary to different degrees. The covariation among traits is thought to reflect properties of the species' genetic architecture and thus can have an impact on evolutionary responses. Furthermore, if morphological integration changes along the history of a group, inferences of past selection regimes might be problematic. Here, we evaluated the stability and evolution of the morphological integration of skull traits in Carnivora by using evolutionary simulations and phylogenetic comparative methods. Our results show that carnivoran species are able to respond to natural selection in a very similar way. Our comparative analyses show that the phylogenetic signal for pattern of integration is lower than that observed for morphology (trait averages), and that integration was stable throughout the evolution of the group. That notwithstanding,...

Brazilian Journal of Veterinary Research and Animal Science

This study reports the factors which led a gated community located in Bragança Paulista (SP, Braz... more This study reports the factors which led a gated community located in Bragança Paulista (SP, Brazil), a non-endemic area for Brazilian Spotted Fever (BSF), to be classified as a Risk Area for transmission of this disease, showing that an increasing resident population of capybaras (Hydrochoerus hydrochaeris) in the area was likely responsible for a proliferation of Amblyomma sculptum ticks and acted as an amplifying host for Rickettsia rickettsii, the main etiologic agent of BSF. We report management actions proposed to control the local tick burden and reduce BSF risk, including measures to control parasitic and free-living tick populations and exclusion of the resident capybara population. Analyses of tick population data and R. rickettsii serology tests indicate that these measures were effective, greatly reducing the environmental burden of Amblyomma sculptum ticks and reducing the BSF transmission risk at the area.

Brazilian journal of biology = Revista brasleira de biologia, Jan 10, 2015

Joint Conference on Language Evolution, 2022

One exciting but often puzzling aspect of the field of Language Evolution is the variety of theor... more One exciting but often puzzling aspect of the field of Language Evolution is the variety of theories and approaches it includes, sometimes with contradictory assumptions or pursuing different questions. It has been argued before that this variety arises in part from different theories of language. I argue that another important factor underlying disparate, sometimes incommensurate approaches are different understandings and definitions of 'evolution', including 'what counts as evolution' and 'what evolution can explain', and suggest that greater attention to discussions about evolution in the philosophy of biology may help untangle differences and similarities between approaches and foster constructive discussions between them.

A integração morfológica determina a quantidade de variação disponível em diferentes direções do ... more A integração morfológica determina a quantidade de variação disponível em diferentes direções do espaço multivariado entre um conjunto de caracteres, e pode assim ter importantes consequências evolutivas, enviesando a direção e a taxa de evolução morfológica em determinadas direções. Assim, estudar a evolução da integração morfológica é importante para entender a evolução fenotípica de uma linhagem. Neste trabalho, utilizo abordagens de genética quantitativa comparativa para estudar a evolução da integração morfológica no crânio em carnívoros da subordem Feliformia, grupo com extensa diversidade filogenética, morfológica e ecológica para o qual análises anteriores de integração analisaram número reduzido de espécies. Para este fim, comparo matrizes de covariância fenotípicas intra-populacionais quantificando a associação entre 35 distâncias lineares no crânio de um conjunto de táxons incluindo todas as sete famílias e mais de um terço da diversidade filogenética atual da subordem. I...

Full Random Skewers table of pairwise comparisons.Values below the diagonal are observed values a... more Full Random Skewers table of pairwise comparisons.Values below the diagonal are observed values and the ones above the diagonal are corrected values. The diagonal contain the matrix repeatabilities

Linear Discriminant Scores for the averages phenotypes for each taxa. LDA scores were used to cal... more Linear Discriminant Scores for the averages phenotypes for each taxa. LDA scores were used to calculate mahalanobis distances and were used as input in comparative analyses

Carnivora Cladogram used in analyses. Three in Newick format with no branch-lengths

Align cytochrome b sequences used to estimate branch-lengths

Individual species phenotypic covariance matrices. Zip file containing 145 CSV format-tables

Morphological integration refers to the fact that different phenotypic traits of organisms are no... more Morphological integration refers to the fact that different phenotypic traits of organisms are not fully independent from each other, and tend to covary to different degrees. The covariation among traits is thought to reflect properties of the species' genetic architecture and thus can have an impact on evolutionary responses. Furthermore, if morphological integration changes along the history of a group, inferences of past selection regimes might be problematic. Here we evaluated the stability and evolution of the morphological integration of skull traits in Carnivora by using evolutionary simulations and phylogenetic comparative methods. Our results show that carnivoran species are able to respond to natural selection in a very similar way. Our comparative analyses show that the phylogenetic signal for pattern of integration is lower than that observed for morphology (trait averages), and that integration was stable throughout the evolution of the group. That notwithstanding, Canidae differed from other families by having higher integration, evolvability, flexibility and allometric coefficients on the facial region. These changes might have allowed canids to rapidly adapt to different food sources, helping to explain not only the phenotypic diversification of the family, but also why humans were able to generate such a great diversity of dog breeds through artificial selection

Brazilian journal of biology = Revista brasleira de biologia, Jan 10, 2015

Brazilian Journal of Veterinary Research and Animal Science, 2018

Brazilian Journal of Veterinary Research and Animal Science

This study reports the factors which led a gated community located in Bragança Paulista (SP, Braz... more This study reports the factors which led a gated community located in Bragança Paulista (SP, Brazil), a non-endemic area for Brazilian Spotted Fever (BSF), to be classified as a Risk Area for transmission of this disease, showing that an increasing resident population of capybaras (Hydrochoerus hydrochaeris) in the area was likely responsible for a proliferation of Amblyomma sculptum ticks and acted as an amplifying host for Rickettsia rickettsii, the main etiologic agent of BSF. We report management actions proposed to control the local tick burden and reduce BSF risk, including measures to control parasitic and free-living tick populations and exclusion of the resident capybara population. Analyses of tick population data and R. rickettsii serology tests indicate that these measures were effective, greatly reducing the environmental burden of Amblyomma sculptum ticks and reducing the BSF transmission risk at the area.

Há um enorme número de pessoas a quem devo agradecer pela ajuda e companhia antes e durante este ... more Há um enorme número de pessoas a quem devo agradecer pela ajuda e companhia antes e durante este trabalho. Como é possível e provável que eu acabe esquecendo parte delas, começo com um agradecimento e um pedido de desculpas a essas. Continuo então com os lembrados diretamente. Ao Prof. Dr. Gabriel Marroig, meu agradecimento pela possibilidade de fazer este mestrado depois de me ausentar da academia por alguns anos, recebendo-me como orientador junto a uma equipe fantástica e me dando a oportunidade de seguir trabalhando com carnívoros, grupo de meu interesse já há tempos. À Dra. Erika Hingst-Zaher, por me introduzir ao estudo dos carnívoros e à morfometria na iniciação científica e pelo apoio e amizade em vários momentos posteriores. À Prof. Dra. Denise Scheepmaker e ao Prof. Dr. Rui Murrieta, por expandirem minha compreensão sobre evolução e sobre ciência como um todo. Ao Fábio Machado (Lugar) e ao Guilherme Garcia (Pato), amigos de longa data e colegas de laboratório desde os tempos da IC, pelas inúmeras discussões, conversas, críticas e ideias (por vezes a um mar de distância), pelo grande apoio e pela companhia em vários momentos. Eu talvez não chegasse ao final sem vocês. À Anna Penna (Papete), companheira de mestrado, pelas conversas e companhia em vários momentos ao longo dos tempos de vida cigana. E aos demais colegas do LEM durante este mestrado-Ogro, Alex, Monique, Tafinha, Dani, Paulinha e Aninha, pelas risadas durante estes anos e pelas diversas conversas, dicas e contribuições sobre diversos aspectos do trabalho-dos teóricos aos burocráticos.

Evolution; international journal of organic evolution, Jan 26, 2018

Morphological integration refers to the fact that different phenotypic traits of organisms are no... more Morphological integration refers to the fact that different phenotypic traits of organisms are not fully independent from each other, and tend to covary to different degrees. The covariation among traits is thought to reflect properties of the species' genetic architecture and thus can have an impact on evolutionary responses. Furthermore, if morphological integration changes along the history of a group, inferences of past selection regimes might be problematic. Here, we evaluated the stability and evolution of the morphological integration of skull traits in Carnivora by using evolutionary simulations and phylogenetic comparative methods. Our results show that carnivoran species are able to respond to natural selection in a very similar way. Our comparative analyses show that the phylogenetic signal for pattern of integration is lower than that observed for morphology (trait averages), and that integration was stable throughout the evolution of the group. That notwithstanding,...

Brazilian Journal of Veterinary Research and Animal Science

This study reports the factors which led a gated community located in Bragança Paulista (SP, Braz... more This study reports the factors which led a gated community located in Bragança Paulista (SP, Brazil), a non-endemic area for Brazilian Spotted Fever (BSF), to be classified as a Risk Area for transmission of this disease, showing that an increasing resident population of capybaras (Hydrochoerus hydrochaeris) in the area was likely responsible for a proliferation of Amblyomma sculptum ticks and acted as an amplifying host for Rickettsia rickettsii, the main etiologic agent of BSF. We report management actions proposed to control the local tick burden and reduce BSF risk, including measures to control parasitic and free-living tick populations and exclusion of the resident capybara population. Analyses of tick population data and R. rickettsii serology tests indicate that these measures were effective, greatly reducing the environmental burden of Amblyomma sculptum ticks and reducing the BSF transmission risk at the area.

Brazilian journal of biology = Revista brasleira de biologia, Jan 10, 2015