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Search Results: 1 - 10 of 11988 matches for " natural selection "
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M. Saadat,P.Amirshahi,D.D. Farhud
Iranian Journal of Public Health , 1996,
Abstract: A total of 3204 ABO and Rh blood groups were investigated in Larestan and Lamerd populations, in Fars province, in Iran. The frequency of the A gene ranged from 16.54% to 21.96, the B gene from 15.85 to 27.77% and that of the d gene from 21.49 to 33.01% ; compared with the gene frequencies of 20.97% for the B and 28.50% for the d in the general population. It seemed that the two populations studied in the present investigation were characterized by a higher B and a lower A gene frequencies. Larestan and Lamerd areas had been malarias for several centuries and because the B phenotype has slight advantage at malarious condition, in appeared that, at least in part, the natural selection counts for the high level of the B gene in Larestanis and Lamerdis compared with that in other populations of Fars province.
Pequi (Caryocar Brasiliense Camb.): informa??es preliminares sobre um pequi sem espinhos no caro?o
Kerr, Warwick Estevam;Silva, Francisco Raimundo da;Tchucarramae, Bdijai;
Revista Brasileira de Fruticultura , 2007, DOI: 10.1590/S0100-29452007000100035
Abstract: one pequi plant, (caryocar brasiliense camb. caryocaraceae) whose fruits had no spines in the kernel, was found in the noth of mato grosso (figures 1 and 2). this is the third most consumed fruit by the populations of the brazilian cerrado and its only deffect is to have the kernel full of spines. the history of its discovery is related.
Natural Selection and Thermodynamics of Biological Evolution  [PDF]
Georgi P. Gladyshev
Natural Science (NS) , 2015, DOI: 10.4236/ns.2015.73013
Abstract: The author of this article proposes that the representation of Charles Darwin and Alfred Wallace’s theory on “variation and selection” in the living world is a reflection of the action of hierarchical thermodynamics. Hierarchical thermodynamics is based on the law of temporal hierarchies and on the principle of substance stability. This principle enables the transmission of thermodynamic information between lower and higher structural hierarchies, in both forward and reverse direction: from nucleic acids to higher structural hierarchies and back. The principle of substance stability, in fact, is the main dynamical and thermodynamic mechanism of natural selection. It is alleged that the natural selection of atoms, molecules, organisms, populations, and other hierarchical structures takes place under the action of a variety of internal factors within organisms and the external environmental factors that can be considered as tropisms. Forms (design) of living organisms are formed as a result of spontaneous and non-spontaneous processes that lead to the adaptation of living systems to the environment. The selection is carried out as a result of the impacts of different energy types and the principle of substance stability at all levels of hierarchical structures. Actions of tropisms are presented by various members of the generalized Gibbs equation.
Sexual selection studies: A NESCent catalyst meeting
Joan Roughgarden,Elizabeth Adkins-Regan,Erol Akay,Jeremy Chase Crawford,Raghavendra Gadagkar,Simon C. Griffith,Camilla A Hinde,Thierry Hoquet,Cailin O’Connor,Zofia M. Prokop,Richard O. Prum,Sharoni Shafir,Samuel S. Snow,Daniel Taylor,Jeremy Van Cleve,Michael Weisberg
PeerJ , 2015, DOI: 10.7287/peerj.preprints.680v2
Abstract: A catalyst meeting on sexual selection studies was held in July 2013 at the facilities of the National Evolutionary Synthesis Center (NESCent) in Durham, NC. This article by a subcommittee of the participants foregrounds some of the topics discussed at the meeting. Topics mentioned here include the relevance of heritability estimates to assessing the presence of sexual selection, whether sexual selection is distinct from natural selection, and the utility of distinguishing sexual selection from fecundity selection. A possible definition of sexual selection is offered based on a distinction between sexual selection as a frequency-dependent process and fecundity selection as a density-dependent process. Another topic highlighted is a deep disagreement among participants in the reality of good-genes, sexy-sons, and run-away processes. Finally, the status of conflict in political-economic theory is contrasted with the status accorded to conflict in evolutionary behavioral theory, and the professional responsibility of sexual-selection workers to consider the ethical dimension of their research is underscored.
Establecimiento y Propagación del Darwinismo en Chile: Recepción y Elaboración de las Ideas
Medel,Rodrigo; Veloso,Alberto;
Gayana (Concepción) , 2009, DOI: 10.4067/S0717-65382009000300002
Abstract: we analyze the social and cultural scenario prevalent at the moment of darwin?s visit to chile. on this basis, we describe the short-and mid-term impact of the beagle voyage upon the cultural environment at that time, and suggest some elements that may have infuenced the settlement and spread of darwin?s ideas at the end of the 19th and frst half of the 20th centuries in chile. we identifed three stages in the process. first, a naturalist stage, related with the direct impact of darwin?s work on the knowledge of biological diversity described in chile at that moment. second, an ideological stage, characterized by extra scientifc debates on darwin?s major ideas. most of this debate was carried out by chilean intellectuals, which focused upon the religious, ethical, social, and educational consequences of darwin?s ideas rather than in their scientifc soundness. third, a scientifc stage, related with the implementation of formal research in evolutionary biology impulsed by the development of the modern synthesis in the frst half of the 20th century. since then, research on evolutionary biology has increased in scope and depth and continues spreading through diverse and new research programs in the country.
O problema da individua??o na biologia à luz da determina??o da unidade de sele??o natural
Chediak, Karla;
Scientiae Studia , 2005, DOI: 10.1590/S1678-31662005000100004
Abstract: the assertion that there are multiple levels of units of natural selection has been used as a way to explain the existence of different levels of biological organization. however these differentiated levels may still be thought from the perspective of the concept of individuation, which also presents gradations. in fact, we consider that the concepts of individual and unit of selection are interrelated, in such way that the stronger the action of selection at a certain level of biological organization the more individuated it will be.
The Capricious Character of Nature
Jaana Keto,Arto Annila
Life , 2012, DOI: 10.3390/life2010165
Abstract: The on-going whole genome sequencing and whole cell assays of metabolites and proteins imply that complex systems could ultimately be mastered by perfecting knowledge into great detail. However, courses of nature are inherently intractable because flows of energy and their driving forces depend on each other. Thus no data will suffice to predict precisely the outcomes of e.g., engineering experiments. All path-dependent processes, most notably evolution in its entirety, display this capricious character of nature.
Expression variation in connected recombinant populations of Arabidopsis thaliana highlights distinct transcriptome architectures
Francisco A Cubillos, Jennifer Yansouni, Hamid Khalili, Sandrine Balzergue, Samira Elftieh, Marie-Laure Martin-Magniette, Yann Serrand, Lo?c Lepiniec, Sébastien Baud, Bertrand Dubreucq, Jean-Pierre Renou, Christine Camilleri, Olivier Loudet
BMC Genomics , 2012, DOI: 10.1186/1471-2164-13-117
Abstract: The utilisation of the novel R/eqtl package (which goal is to automatize and extend functions from the R/qtl package) allowed us to map 4,290 and 6,534 eQTLs in the Cvi-0 × Col-0 and Bur-0 × Col-0 recombinant populations respectively. In agreement with previous studies, we observed a larger phenotypic variance explained by eQTLs in linkage with the controlled gene (potentially cis-acting), compared to distant loci (acting necessarily indirectly or in trans). Distant eQTLs hotspots were essentially not conserved between crosses, but instead, cross-specific. Accounting for confounding factors using a probabilistic approach (VBQTL) increased the mapping resolution and the number of significant associations. Moreover, using local eQTLs obtained from this approach, we detected evidence for a directional allelic effect in genes with related function, where significantly more eQTLs than expected by chance were up-regulated from one of the accessions. Primary experimental data, analysis parameters, eQTL results and visualisation of LOD score curves presented here are stored and accessible through the QTLstore service database http://qtlstore.versailles.inra.fr/ webcite.Our results demonstrate the extensive diversity and moderately conserved eQTL landscape between crosses and validate the utilisation of expression traits to explore for candidates behind phenotypic variation among accessions. Furthermore, this stresses the need for a wider spectrum of diversity to fully understand expression trait variation within a species.Most traits vary quantitatively between individuals and are significantly influenced by genetic variation and its interaction with the environment. In general, transcript abundance of a gene can be considered as a quantitative trait since it differs between individuals with respect to genetic factors [1,2]. The utilisation of technologies such as microarray and, lately, next generation sequencing, allowed the simultaneous quantification of thousands of tra
Influência de cultivares de amoreira Morus spp. sobre a produ??o e qualidade de casulos de bicho-da-seda, Bombyx mori L. (Lepidoptera: Bombycidae)
Meneguim, Ana M.;Lovato, Lidiana;Silva, Roberta Z. da;Yamaoka, Ruy S.;Nagashima, Getúlio T.;Pasini, Amarildo;
Neotropical Entomology , 2007, DOI: 10.1590/S1519-566X2007000500006
Abstract: the success of sericiculture greatly depends on the availability of mulberry cultivars with agronomic characteristics that maximize the production and quality of silkworm, bombyx mori l., cocoons. the effect of the cultivars miura (standard) and korin, and the hybrids sm 14, sm 63, sk 1, sk 4 and fm 86 was evaluated on silkworm development, and on cocoon production and quality, at the instituto agron?mico do paraná, iapar, in londrina, pr, brazil (23 ± 3°c; 61 ± 8% rh). the experiment was arranged in a randomized block design with four replicates. larvae feeding either on ?sk 4? or on ?korin? showed a higher weight compared to that of larvae feeding on ?miura". cocoon weight (both sexes) and pupae weight (male) obtained with larvae fed on sk 4 were higher compared with that of insects that fed on ?miura?; there was no difference among the remaining treatments. silk net weight was independent of the cultivar used. cocoon shell weight was similar amongst insects raised on ?miura? and on the other mulberry materials. the percentage of cocoon spinning was higher than 90% in all treatments, with the spinning concentrating in the first two days. the proportion of first grade cocoons varied from 80% (sk4) to 90%. the results obtained with the studied cultivars were either similar or superior to that of the standard cultivar miura with emphasis to ?sk 4?, thus showing the potential use of these cultivars in sericulture in the state of paraná.
Díaz Piedrahita,Santiago;
Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales , 2012,
Abstract: the article exposes the way in which the intellectual community of colombia received darwin's works, specifically the theory of evolution through natural selection. overall, his arguments were considered utilitarian and interpreted from a purely religious or political perspective, rather than being understood as a biological theory. in addition, the text presents testimonies that reflect the political times and the prevailing ideologies of the late 19th and early 20th centuries.
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