Artículos con la etiqueta ‘evolución artificial’

Categorization of exchange fluxes explains the four relational models

Por • 25 dic, 2013 • Category: sociologia

The theory of Relational Models (RMs) posits four elementary models of relationships governing all human interactions, singly or in combination: Communal Sharing, Authority Ranking, Equality Matching, and Market Pricing. By considering two agents that can act in one out of three ways towards one another: give resource A, give resource B, or give nothing, we find four discrete categories of exchange fluxes that map unequivocally to the four RMs. This categorization shows that the RMs form an exhaustive set of all possible elementary exchanges. Hence, the fluxes categorization answers why there are just four RMs and explains their discreteness. By considering the costs associated with extracting resources, storing them and implementing each flux category, we are able to propose conditions under which each RM should evolve. We also logically deduce the singular nature of the Authority Ranking model. Our propositions are compatible with anthropological, ethnological and historical observations and can be tested analytically and/or numerically via agent-based computer simulations.

Evolution in a Changing Environment

Por • 24 abr, 2013 • Category: Ambiente

We propose a simple model for genetic adaptation to a changing environment, describing a fitness landscape characterized by two maxima. One is associated with «specialist» individuals that are adapted to the environment; this maximum moves over time as the environment changes. The other maximum is static, and represents «generalist» individuals not affected by environmental changes. The rest of the landscape is occupied by «maladapted» individuals. Our analysis considers the evolution of these three subpopulations. Our main result is that, in presence of a sufficiently stable environmental feature, as in the case of an unchanging aspect of a physical habitat, specialists can dominate the population. By contrast, rapidly changing environmental features, such as language or cultural habits, are a moving target for the genes; here, generalists dominate, because the best evolutionary strategy is to adopt neutral alleles not specialized for any specific environment. The model we propose is based on simple assumptions about evolutionary dynamics and describes all possible scenarios in a non-trivial phase diagram. The approach provides a general framework to address such fundamental issues as the Baldwin effect, the biological basis for language, or the ecological consequences of a rapid climate change.

L’hypothétique mutation à la source du succès évolutif des hominidés

Por • 28 ago, 2011 • Category: Opinion

Pat Shipman a récemment proposé de compléter cette première explication par une autre, exposée dans son livre «The Animal Connection. A new perspective on what makes us human» (W.W. Norton and Co, juin 2011). Elle ne remet pas en cause l’explication de l’hominisation par l’usage de l’outil, mais elle propose d’ajouter un facteur explicatif tout aussi puissant selon elle : la coopération qui s’est établie des les origines entre les hominiens et différentes espèces animales les ayant aidé à s’imposer dans un monde peuplé initialement de prédateurs redoutables.

Du génome du singe au génome humain

Por • 8 abr, 2011 • Category: Ciencia y tecnología

A partir de ces premières recherches, ils ont identifié un nombre apparemment considérables d’exemples (508), montrant que le génome humain se différenciait de celui des autres espèces non par l’ajout de nouvelles séquences de régulation mais par la disparition ou l’inhibition de séquences actives dans les autres espèces. Autrement dit, ce ne fut pas par l’addition de nouveaux gènes ou nouvelles séquences d’ADN que les hominidés se sont spécifiés, mais par la soustraction de gènes et séquences présents depuis des millions d’années chez les autres espèces.

On Phenomenology of Complex Scientific Systems

Por • 26 feb, 2011 • Category: Filosofía

Performance evolution of a number of complex scientific and technical systems demonstrate exponential progress with time exp(+t/C) . An explanation of the characteristic exponential progress is offered.