En este artículo argumento que para la Síntesis extendida resulta imperioso reemplazarlos modelos causales tradicionales en biología, el de causas próximas— últimas y el de lacausalidad lineal ascendente, debido a su incapacidad para capturar la causalidad biológicacompleja que describen la mayoría de áreas de investigación en la actualidad. Estas nuevastendencias muestran la necesidad de reconceptualizar la causalidad y así permitir la construcciónde modelos multinivel que conecten bidireccionalmente diversos niveles de organizacióny diferentes escalas de tiempo. La causalidad multinivel es fundamental en (...) losprocesos de organización natural, por lo que, argumento, la extensión de la síntesis debeubicarla en su base. (shrink)

In this article we argue that the classical—linear and bottom-up directed—models of causation in biology, and the ‘‘proximate/ultimate’’ dichotomy, are inappropriate to capture the complexity inherent to biological processes. We introduce a new notion of ‘‘multilevel causation’’ where old dichotomies such as proximate/ultimate and bottom-up/ top-down are reinterpreted within a multilevel, web-like, approach. In briefly reviewing some recent work on complexity, EvoDevo, carcinogenesis, autocatalysis, comparative genomics, animal regeneration, phenotypic plasticity, and niche construction, we will argue that such reinterpretation is a (...) necessary step for the advancement of the ‘‘Extended Synthesis.’’. (shrink)

In this paper, using a multilevel approach, we defend the positive role of natural selection in the generation of organismal form. Despite the currently widespread opinion that natural selection only plays a negative role in the evolution of form, we argue, in contrast, that the Darwinian factor is a crucial (but not exclusive) factor in morphological organization. Analyzing some classic arguments, we propose incorporating the notion of ‘downward causation’ into the concept of ‘natural selection.’ In our opinion, this kind of (...) causation is fundamental to the operation of selection as a creative evolutionary process. (shrink)