http://precedings.nature.com/tags/adaptation Recently posted documents tagged with 'adaptation' Nature Publishing Group en Nature Precedings http://precedings.nature.com/images/header_logo.gif http://precedings.nature.com http://precedings.nature.com/documents/3360/version/1 In biology, spandrels are phenotypic traits that evolve through their underlying developmental, genetic, and/or structural links to another trait under selection1, 2, 3. Despite the importance of the concept of spandrels in biology, empirical examples of spandrels are exceedingly rare at the organismal level2, 3. Here we test whether body size evolution in insular populations of a snake (Elaphe quadrivirgata) is the result of an adaptive response to differences in available prey, or the result of a non-adaptive spandrel resulting from selection on gape size. In contrast to previous hypotheses, Mantel tests show that body size does not coevolve with diet. However, gape size tightly matches diet (birds vs. lizards) across populations, even after controlling for the effects of body size, genetic, and geographic distance. Moreover, gape and body size show a strong degree of phenotypic covariation. Thus, the dramatic insular body size variation among E. quadrivirgata populations is at least partially caused by its underlying phenotypic covariation with gape size rather than the result of direct selection on overall body size. http://precedings.nature.com/documents/3360/version/1 Wed, 01 Jul 2009 13:57:23 UTC Insular gigantism and dwarfism in a snake, adaptive response or spandrel to selection on gape size? hdl:10101/npre.2009.3360.1 2009-07-01 Shawn Vincent Nature Precedings 2009-07-01T13:57:23Z Manuscript Ecology Evolutionary Biology http://creativecommons.org/licenses/by/3.0/ http://precedings.nature.com/documents/2246/version/1 When an image is presented to one eye and a very different image is presented to the corresponding location of the other eye, they compete for conscious representation, such that only one image is visible at a time while the other is suppressed. Called binocular rivalry, this phenomenon and its deviants have been extensively exploited to study the mechanism and neural correlates of consciousness. In this paper, we propose a framework, the unconscious binding hypothesis, to distinguish unconscious processing from conscious processing. According to this framework, the unconscious mind not only encodes individual features but also temporally binds distributed features to give rise to cortical representation, but unlike conscious binding, such unconscious binding is fragile. Under this framework, we review evidence from psychophysical and neuroimaging studies, which suggests that: (1) for invisible low level features, prolonged exposure to visual pattern and simple translational motion can alter the appearance of subsequent visible features (i.e. adaptation); for invisible high level features, although complex spiral motion cannot produce adaptation, nor can objects/words enhance subsequent processing of related stimuli (i.e. priming), images of tools can nevertheless activate the dorsal pathway; and (2) although invisible central cues cannot orient attention, invisible erotic pictures in the periphery can nevertheless guide attention, likely through emotional arousal; reciprocally, the processing of invisible information can be modulated by attention at perceptual and neural levels. http://precedings.nature.com/documents/2246/version/1 Tue, 02 Sep 2008 18:55:51 UTC Seeing the invisible: The scope and limits of unconscious processing in binocular rivalry hdl:10101/npre.2008.2246.1 2008-09-02 Zhicheng Lin Nature Precedings 2008-09-02T18:55:51Z Manuscript Neuroscience http://creativecommons.org/licenses/by/3.0/ http://precedings.nature.com/documents/2123/version/1 Convergence can mislead phylogenetic inference by mimicking shared ancestry, but has been detected only rarely in molecular evolution. Here, we show that significant convergence occurred in snake and agamid lizard mitochondrial genomes. Most evidence, and most of the mitochondrial genome, supports one phylogenetic tree, but a subset of mostly amino acid-altering mitochondrial sites strongly support a radically different phylogeny. These sites are convergent, probably selected, and overwhelm the signal from other sites. This suggests that convergent molecular evolution can seriously mislead phylogenetics, even with large data sets. Radical phylogenies inconsistent with previous evidence should be treated cautiously. http://precedings.nature.com/documents/2123/version/1 Mon, 28 Jul 2008 10:16:54 UTC An ancient adaptive episode of convergent molecular evolution confounds phylogenetic inference hdl:10101/npre.2008.2123.1 2009-03-04 A.P. Jason de Koning* Nature Precedings 2008-07-28T10:16:54Z Manuscript Genetics & Genomics Bioinformatics Evolutionary Biology http://creativecommons.org/licenses/by/3.0/ http://precedings.nature.com/documents/1713/version/1 Landscapes in ecology have a profound influence on the adaption and evolution of competing populations for resources. We are interested in how altruistic populations survive in the presence of selfish individuals in a non-stirred, closed and complex nutrient landscape. Well-stirred (landscape-free) but closed environments have a depressing future when selfish individuals arise in a population, a fate known as the tragedy of the Commons. Over-exploitation of a well-stirred communal habitat by selfish individuals which do not follow rules of communal self-regulation ends up in the elimination (extinction) of both the original altruistic inhabitants and the selfish population. In the context of bacterial population, the Commons tragedy that occurs is the consumption of limited resources by the individuals, resulting in metabolic stressing of the bacteria and growth advantages to be gained by defection from a ``social contract” of altruistic cooperation. There is no avoidance of this tragedy and the collapse of an original altruistic wild-type population by an emergent selfish population in a well-stirred but closed environment is inevitable. However, there is a fundamental difference between resource exploitation in a well-stirred homogenous commons and in a heterogenous landscape of nutrients which is not stirred. We show here using a non-stirred nanofabricated habitat landscape that altruists and selfish bacteria can in fact coexist, that they can maintain phenotype diversity and avoid the tragedy of the Commons. This emergent spatial segregation of competing populations under stress greatly changes, we believe, our perception of the true sophistication of bacterial response to stress and competition, and has broad implications for the adaptive strategies of higher organisms under stress in complex environments. http://precedings.nature.com/documents/1713/version/1 Mon, 24 Mar 2008 16:23:42 UTC Selfish and Altruistic Bacterial Populations Maximize Fitness Under Stress by Local Segregation hdl:10101/npre.2008.1713.1 2008-04-10 Robert Austin Nature Precedings 2008-03-24T16:23:42Z Manuscript Ecology Genetics & Genomics Microbiology http://creativecommons.org/licenses/by/3.0/ http://dx.doi.org/10.1038/npre.2008.1606.3 Eight species of Rhinocryptidae are recognized from Chile. Moreover, morphological, ecological and behavioral differences among two lineages of Scytalopus and two species of Pteroptochos are unclear. According to our results, there are no decisive criteria differentiating among subspecific sister taxa of Scelorchilus albicollis, S.rubecula and Pteroptochos megapodius. Here we discuss the speciation of the chilean Rhinocryptidae based in their behaviour and we carried out an integrated analysis with specie outgroup Cinclodes oustaleti (Furnariidae). We propose a new methodology based on ecological and behavioural patterns in order to understand the concept of speciation in this group of birds.Key words: Rhynocriptidae, Pteroptochos, Scytalopus, Scelorchilus, Eugralla, Furnariidae, behaviour, adaptation, evolutionary clues. http://dx.doi.org/10.1038/npre.2008.1606.3 Wed, 19 Mar 2008 19:34:10 UTC Differences of morphological and ecological characters among lineages of Chilean Rhinocryptidae in relation an sister lineage of Furnariidae. doi:10.1038/npre.2008.1606.3 2008-03-19 Alejandro Correa Rueda Nature Precedings 2008-03-19T19:34:10Z Manuscript Ecology http://creativecommons.org/licenses/by/3.0/ http://dx.doi.org/10.1038/npre.2008.1606.2 Eight species of Rhinocryptidae are recognized from Chile. Moreover, morphological, ecological and behavioral differences among two lineages of Scytalopus and two species of Pteroptochos are unclear. According to our results, there are no decisive criteria differentiating among subspecific sister taxa of Scelorchilus albicollis, S. rubecula and Pteroptochos megapodius. Here we discuss the speciation of the chilean Rhinocryptidae based in their behaviour. We propose a new methodology based on ecological and behavioural patterns in order to understand the concept of speciation in this group of birds. http://dx.doi.org/10.1038/npre.2008.1606.2 Thu, 06 Mar 2008 17:42:28 UTC Differences of morphological and ecological characters among lineages of Chilean Rhinocryptidae in relation an sister lineage of Furnariidae. doi:10.1038/npre.2008.1606.2 2008-03-06 Alejandro Correa Rueda Nature Precedings 2008-03-06T17:42:28Z Manuscript Ecology http://creativecommons.org/licenses/by/3.0/ http://dx.doi.org/10.1038/npre.2008.1606.1 Eight species of Rhinocryptidae are recognized from Chile. Moreover, morphological, ecological and behavioral differences among two lineages of Scytalopus and two species of Pteroptochos are unclear. According to our results, there are no decisive criteria differentiating among subspecific sister taxa of Scelorchilus albicollis, S. rubecula and Pteroptochos megapodius. Here we discuss the speciation of the chilean Rhinocryptidae based in their behaviour. We propose a new methodology based on ecological and behavioural patterns in order to understand the concept of speciation in this group of birds. http://dx.doi.org/10.1038/npre.2008.1606.1 Tue, 19 Feb 2008 16:47:25 UTC Differences of morphological and ecological characters among lineages of Chilean Rhinocryptidae in relation an sister lineage of Furnariidae. doi:10.1038/npre.2008.1606.1 2008-02-19 Alejandro Correa Rueda Nature Precedings 2008-02-19T16:47:25Z Manuscript Ecology http://creativecommons.org/licenses/by/3.0/ http://precedings.nature.com/documents/1353/version/1 Evidence exists for a non-verbal capacity to apprehend number, in humans1 (including infants2,3) and in other primates4-6. Here we show that perceived numerosity is susceptible to adaptation, along with primary visual properties of a scene like colour, contrast, size and speed. Apparent numerosity was decreased by adapting to large numbers of dots and increased by adapting to small numbers, the effect depended entirely on the numerosity of the adapter, not on contrast, size, orientation or pixel density, and occurred with very low adapter contrasts. We suggest that numerosity is also an independent primary visual property, not reducible to others like spatial frequency or density of texture7. http://precedings.nature.com/documents/1353/version/1 Tue, 20 Nov 2007 12:32:03 UTC A visual sense of number hdl:10101/npre.2007.1353.1 2008-04-22 David Burr Nature Precedings 2007-11-20T12:32:03Z Manuscript Neuroscience http://creativecommons.org/licenses/by/3.0/