En este texto, presento a Lamarck, como un autor que debe ser considerado, no solo como uno de fundadores de la biología, sino uno de los precursores del positivismo. Se examinarán nociones de “fuerza vital”, organización, “plan de la naturaleza”, “sentimiento interior” y hábito, pilares de su teoría de la transformación. Esta teoría fusiona el determinismo inherente al “plan de la naturaleza” (PN) con el papel más flexible del “sentimiento interior” (SI) y el hábito en la modificación. Es así como, (...) Lamarck defendió un holismo materialista que justifica la imagen de una naturaleza que, al organizar la materia, da lugar a la generación espontánea de seres vivos simples que a lo largo del tiempo se transforman incrementando los grados de organización, culminando con la aparición del hombre. Idea que Comte extrapoló para justificar un progreso social atado a la aparición de las ciencias positivas. Este trabajo también evalúa la crítica de Comte a Lamarck acerca del papel del medioambiente, cuyo potencial de cambio estaría limitado por “la existencia de “obstáculos interiores” a la modificación, superados en los humanos mediante la emergencia de la sociedad. Ambos autores estuvieron influenciados por François Quesnay, quien propugnaba una sociedad regida por una ética basada en una ley natural biológica. Pero, mientras Lamarck anticipaba el riesgo de la autoextinción humana, Comte consideraba que el verdadero progreso se lograría al convertir esa ley natural en fundamento de una nueva religión secular. (shrink)

This paper defends an internalist perspective of selection based on the hypothesis that considers living evolutionary units as Maxwell's demons (MD) or Zurek's Information Gathering and Using Systems (IGUS). Individuals are considered as IGUS that extract work by means of measuring and recording processes. Interactions or measurements convert uncertainty about the environment (Shannon's information, H) into internalized information in the form of a compressed record (Chaitin's algorithmic complexity, K). The requirements of the model and the limitations inherent to its formalization (...) are discussed. This approach offers an alternative view to the causes of evolutionary variations which goes beyond the classical Lamarckian-Darwinian controversy. I argue that random variations only apply near-to-equilibrium at the time organisms have attained structural closure, and that a speed up of mutation rates that facilitates the production of directed variations occurs far-from-equilibrium due to organisms' openness to the surrounding conditions. However, real organisms are located somewhere between the above two cases and thus, operate at an intermediate stage where there is a maximum efficiency of H/K conversion. In consequence, IGUS keep their autonomy and evolving capacity by compromising between external circumstances and inner constraints. This compromise is made possible by closure regulation. Likewise, this model explains why nature has favored the selection of agents capable of selectively recording a partial description of their environment. (shrink)

In this paper we propose a theoretical model of protein folding and protein evolution in which a polypeptide (sequence/structure) is assumed to behave as a Maxwell Demon or Information Gathering and Using System (IGUS) that performs measurements aiming at the construction of the native structure. Our model proposes that a physical meaning to Shannon information (H) and Chaitin's algorithmic information (K) parameters can be both defined and referred from the IGUS standpoint. Our hypothesis accounts for the interdependence of protein folding (...) and protein evolution through mutual influencing relationships mediated by the IGUS. In brief, IGUS activity in protein folding determines long term tendencies that emerge at the evolutionary time-scale.Thus, protein evolution is a consequence of measurements executed by proteins at the cellular level, where the IGUS imposes a tendency to attain a highly unique stable native form that promotes the updating of the information content. The folding kinetics observed is, thus, the outcome of an evolutionary process where the polypeptide-IGUS drives the evolution of its linear sequence. Finally, we describe protein evolution as an entropic process that tends to increase the content of mutual algorithmic information between the sequence and the structure. This model enables one: 1. To comprehend that full determination of the three-dimensional structure by the linear sequence is a tendency where satisfaction is only possible at thermodynamic equilibrium .2. To account for the observed randomness of the amino acid sequences. 3. To predict an alternation of periods of selection and neutral diffusion during protein evolutionary time. (shrink)

En este artículo defendemos la necesidad de reformular los conceptos de constreñimiento del desarrollo y variación considerando trabajos empíricos y teóricos recientes, principalmente sobre genes Hox, estado filotípico y morfogénesis. Argumentamos que la noción de variación isotrópica e ilimitada asociada con las teorías darwinianas y neodarwinianas deben ser reconsideradas a la luz de los aportes recientes de la biología del desarrollo. En esta visión, la variación estaría constreñida y sesgada. Esta reforma del concepto de variación coincide con la reformulación del (...) de constreñimiento, los cuales serían entendidos como un factor causal positivo en la evolución, en contraposición a como suelen ser entendidos en biología. (shrink)