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| Registros recuperados: 176 | |
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| CHAVES,ÓSCAR M. |
| The scientific revolution probably began at 16th century with the heliocentric theory of the eminent astronomer Nicolaus Copernicus, but it was culminated with the masterful discoveries of Galileo Galilei and Isaac Newton at 17th century who revealed that planet movements around the sun and other similar phenomena can be explained by simple mechanical laws of physics and astronomy. However, the origin, complexity and configuration of living beings remained in the mystery until 19th century, with the publication of "On the origin of species". In this essay I discuss the importance of the Darwinian scientific revolution, its beginnings, and the main objections of creationists to his evolutionary ideas. Darwin demonstrated that the origin and complexity of... |
| Tipo: Journal article |
Palavras-chave: Creationism; Darwin; Evolution; Religion; Scientific revolution. |
| Ano: 2010 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2010000200004 |
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| VARGAS,ALEXANDER O. |
| It has been argued that the study of natural selection and quantitative genetics should have a central role in evolutionary thinking and undergraduate teaching in Chile. Extensive operational use of the concept of natural selection may seem consistent with this argument. However, advances of evolutionary knowledge in independent fields such as phylogenetic analysis, developmental evolution, and paleontology cannot be ignored. I argue here that the role of natural selection in contemporary evolutionary biology can be compared to that of Newtonian mechanics in contemporary physics: it can describe a given domain of observations, but it is insufficient to handle the different sources of evolutionary knowledge. Overemphasis on natural selection as the... |
| Tipo: Journal article |
Palavras-chave: Evolution; History; Development; Epigenesis; Drift. |
| Ano: 2005 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2005000400012 |
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| CARSON,HAMPTON L.. |
| This is a personal essay commemorating Brncic as a keen naturalist/evolutionist in the best Darwinian sense. His innate curiosity, so important in a scientist, led him to the discovery of cenain unique drosophilid flies in Chile. The life cycle of one species of flower-fly (Drosophila flavopilosa) is of special interest. Females oviposit in fresh flowers of a solanaceous plant that is widespread in Chilean valleys. Twenty years of combined ecological and genetic work, carried out on this species, pioneers the use of a highly specialized Drosophila species in the study of population genetics and evolution. Many eco-genetic features are revealed that are important supplements to observations made on the widely-studied generalist species of the genus |
| Tipo: Journal article |
Palavras-chave: Flower-breeding Drosophila; Genetic specialization; Ecology; Population genetics; Evolution. |
| Ano: 2001 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2001000000008 |
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| TORO,G. CECILIA. |
| In higher eukaryotes, the nuclear DNA is organized for transcription, replication and mitosis in competent chromatin and chromosomes. The basic unit of chromatin is the nucleosome. This entity is formed by 168 base pairs of DNA wound around an octamer of histones, this octamer of histones consist of two copies of H2A, H2B, H3 and H4. The DNA is sealed in its input and output point by a histone linker: histone H1. Histones were supposed to be very conserved proteins. However, during the past few years it was found that these proteins present a high degree of divergency in several lower eukaryotes. In Trypanosoma, it was found that histones H3 and H4, which are at the center of the nucleosomal organization, showed more than 30 % of divergency, while histone... |
| Tipo: Journal article |
Palavras-chave: Histones; Evolution. |
| Ano: 2001 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2001000000020 |
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| THIEL,MARTIN. |
| Many crustacean species show extended parental care (XPC) for fully developed juvenile offspring. Herein, the present state of knowledge of the major patterns and consequences of XPC is reviewed, and furthermore important future research topics are identified. Crustaceans with XPC are found in marine, freshwater and terrestrial environments, but care for late juvenile stages appears to be more common in terrestrial environments. In all species, females participate or even take the main share of XPC activities. Crustaceans that carry their offspring during XPC commonly release early juvenile stages, while species inhabiting particular microhabitats may host offspring until these have reached subadult or adult stages. Apart from providing a suitable and safe... |
| Tipo: Journal article |
Palavras-chave: Crustacea Peracarida reproduction parental care habitat; Evolution. |
| Ano: 2003 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2003000200007 |
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| GALLARDO,MILTON. |
| Genome data analysis indicates that the major evolutionary transitions have been driven by substantial increases in genomic complexity. These increases, accounting for novelty in evolution, have proceeded mainly by gene duplication. This idea, advanced by <A HREF="#OHNO">Ohno (1968)</A>, remains current in the study of several organisms whose genomes have been sequenced. Maize, yeast, and humans contain more paralogons than would be expected to occur by chance, and this supports the contention that gene families were not formed de novo, but by large-scale DNA duplications. Lineage hybridization emerges as an efficient and widespread mechanism to create evolutionary novelty by recruiting redundant genes to new roles. Lateral gene transfer... |
| Tipo: Journal article |
Palavras-chave: Gene duplication; Genome; Genetics; Evolution; Macroevolution; Evolutionary theory. |
| Ano: 2003 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2003000400013 |
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| VALENZUELA,CARLOS Y. |
| The synthetic theory of evolution proposes that biotic variations generated by mutation are mostly fixed, lost or maintained polymorphic by natural selection, with a marginal effect due to genetic drift. Based on the theory of autopoiesis some authors have proposed that selection is unable to explain most evolutionary changes, and natural or phenotype drift and epigenesis are the mechanisms that explain most of evolution. This view misunderstands basic evolutionary notions. Selection is a natural process that occurs with or without evolution; it does not explain evolution, it is a factor of the evolutionary process. The concept of autopoiesis implies an invariant condition of living beings, thus, it cannot explain and even less produce evolution conceived... |
| Tipo: Journal article |
Palavras-chave: Autopoiesis; Evolution; Natural drift; Neutral evolution; Selection; Synthetic theory. |
| Ano: 2007 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2007000100009 |
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| Alfonso Molina,C; Vilchez,Susana. |
| Kin selection could provide an explanation for social behavior in bacteria. The production of public goods such as extracellular molecules is metabolically costly for bacteria but could help them to exploit nutrients or invade a host. Some bacterial cells called social cheaters do not produce public goods; however, they take advantage of these extracellular molecules. In this review, the relationships between social behavior, cooperation, and evolution of bacterial pathogenicity are analyzed. This paper also examines the role of horizontal transfer of genes encoding for virulence factors and how the movement of mobile genetic elements would influence the pathogenicity and social relationships. Moreover, the link between ecological relationships and... |
| Tipo: Journal article |
Palavras-chave: Cooperation; Evolution; Pathogenicity; Public goods. |
| Ano: 2014 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2014000100013 |
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| Demarco,Diego. |
| ABSTRACT Species of Apocynaceae stand out among angiosperms in having very complex flowers, especially those of asclepiads, which belong to the most derived subfamily (Asclepiadoideae). These flowers are known to represent the highest degree of floral synorganization of the eudicots, and are comparable only to orchids. This morphological complexity may also be understood by observing their glands. Asclepiads have several protective and nuptial secretory structures. Their highly specific and specialized pollination systems are associated with the great diversity of glands found in their flowers. This review gathers data regarding all types of floral glands described for asclepiads and adds three new types (glandular trichome, secretory idioblast and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Anatomy; Apocynaceae; Asclepiadoideae; Diversity; Evolution; Flower; Secretory structures. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062017000300477 |
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| Zappelini,Julia; Souza,Luiz Gustavo; Guerra,Miguel Pedro; Pescador,Rosete. |
| ABSTRACT Although karyotype features are useful data for evolutionary studies, cytogenetic data in Bambusoideae are mainly based only on chromosome counts. The first comparative cytogenetic analysis of three Neotropical woody bamboo species - Guadua chacoensis, G. angustifolia and Chusquea tenella - was undertaken based on new and reviewed chromosome counts, CMA/DAPI double staining, fluorescent in situ hybridization (FISH) with 35S and 5S rDNA probes, and genome size estimation. The two species of Guadua were found to have 2n = 46 chromosomes, while the first record for C. tenella was 2n = 44. Only one pair of CMA+/DAPI- was detected on the terminal region of metacentric chromosomes in all three species. Likewise, one pair of 5S and 35S rDNA sites was... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Chusquea; Cytogenetics; Diploidization; Evolution; Guadua; Polyploidy. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062020000400673 |
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| Woltz,Ph; Gajardo,R; Ferreira,A.G. |
| The anatomy of 112 species out of the 184 at present recognized is compared. The evolutionary sequence proposed shows in several different "series" the passage by successive transformations from an ancestral type with short one-nerved leaves, well-developed sub-epidermis and many resin canals to those with long wide leaves, first one-nerved then several-nerved, with reduced sub-epidermis and few resin canals. An over-evolved condition sometimes produces at the end of a "série" an apparent reversion to the ancestral type: leaves short or reduced to fleshy scales with late proliferation of canals separated in the mesophyll. A striking correlation between foliar anatomy and geographic latitude suggests, as with vascular evolution in seedlings at the cotyledon... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Podocarpineae; Evolution; Anatomy comparative. |
| Ano: 1987 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33061987000200002 |
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| SCHNEIDER,HORACIO. |
| Four DNA datasets were combined in tandem (6700 bp) and Maximum parsimony and Neighbor-Joining analyses were performed. The results suggest three groups emerging almost at the same time: Atelidae, Pitheciidae and Cebidae. The total analysis strongly supports the monophyly of the Cebidae family, grouping Aotus, Cebus and Saimiri with the small callitrichines. In the callitrichines, the data link Cebuela to Callithrix, place Callimico as a sister group of Callithrix/Cebuella, and show Saguinus to be the earliest offshoot of the callitrichines. In the family Pithecidae, Callicebus is the basal genus. Finally, combined molecular data showed congruent branching in the atelid clade, setting up Alouatta as the basal lineage and Brachyteles-Lagothrix as a sister... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: New World monkeys; Platyrrhine; Taxonomy; Molecular; Evolution. |
| Ano: 2000 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652000000200005 |
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| MOTHÉ,DIMILA; AVILLA,LEONARDO S.; ZHAO,DESI; XIE,GUANGPU; SUN,BOYANG. |
| ABSTRACT The "Yanghecun specimen", a proboscidean specimen represented by a mandible from Miocene of China and previously described as Gomphotheriidae, is here reviewed and described as a new genus and species of Mammutidae: Sinomammut tobieni. This taxon is a longirostrine mastodon, lacking lower tusks, and bearing a wide last molar with oblique and non-inflated lophids, broad transverse interlophids, and yoke-like wear figures. Phylogenetic analysis of Mammutidae based on dental and mandibular features recovered S. tobieni as sister group of the mastodon Mammut. The longirostrine condition and the well-developed lower incisors seem to be primitive for Mammutidae, while the brevirostry is the derived condition, probably emerged during the middle Miocene... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Evolution; Longirostrine symphysis; Mammutidae; Miocene; Proboscidea. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652016000100065 |
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| SILVA,PRISCILLA A. DA; BORBA,VICTOR H.; DUTRA,JULIANA M.F.; LELES,DANIELA; DA-ROSA,ATILA A.S.; FERREIRA,LUIZ F.; ARAUJO,ADAUTO. |
| Cynodonts represent the transition from reptiles to mammals. They are classified as synapsids, or tetrapod animals with mammalian characteristics. We present here the finding of helminth eggs in a coprolite identified as of cynodont origin dated of nearly 240 million years. Microscopy revealed the presence of very well preserved intestinal parasite eggs. Up to now we identified an ascarid egg by morphological characteristics. Based on a previous description of the new genus Ascarites Poinar Jr and Boucot 2006 in coprolites of iguanodons from Belgium, we propose a new species,Ascarites rufferi n.sp. in cynodonts, a host that inhabited the Southern Region of Brazil in the Triassic period. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Ascarids; Coprolites; Cynodont; Evolution; Paleoparasitology. |
| Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652014000100265 |
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| Registros recuperados: 176 | |
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