Reconstruint Darwin, cent cinquanta anys després

Abstract

Darwinism is an idea that disrupted the creationist biological order, as well as the social and religious ones, because it proposes that species, humans included, derive from each other by natural selection. This dangerous idea has been challenged from different sides. Fossil record, due to its discontinuity and imperfection, has been referred to by creationists to oppose gradual darwinism. Some paleontologists have also interpreted this discontinuity to negate the gradual model of natural selection. The evolution of form, absent in the neodarwinian synthesis, has been a traditional stronghold argument against darwinism. Morphological changes have been often explained as the outcome of evolutionary mechanisms different from darwinian selection. Current molecular approaches have unveiled how morphological variation is enacted by gene regulatory networks. This regulatory variability is the raw material for natural selection in the same way as protein-coding variability, making other mechanisms of evolution unnecesary. Molecular evolution has proved also that complexity is not irreducible, as advocated by the defenders of intelligent design. The darwinian interplay between random mutations and oportunistic natural selection (a deterministic mechanism) is bolstered by comparative genomics and molecular and developmental genetics. All this evidence makes the finding of a new Darwin unnecesary, if not preposterous, as some have proposed, although it may ask for a reconstruction of the new synthesis.