Clarificando a Evolução Biológica e cultivando a sua unidade

Abstract

The pre-university teaching of Biology and Geology refers to Evolutionary Theory as the necessary scientific explanation for the diversity of species within their underlying unity by descent. This is a subject in which many teachers feel somewhat uneasy, and end up settling for simplistic formulations, even sometimes less rigorous ones due to the interference of the mass media; on the other hand, they all desire a critical autonomy that will allow them to care the best possible for the training they provide, as well as to evaluate and clarify the notions that circulate. Admittedly, the mathematical formulations of Evolutionary Theory are often discouraging, but the real problem lies in the challenge of penetrating the controversies that divide scientists, which inadvertently propagate a notion of relativism that is essentially misleading. It becomes necessary to provide a critical narrative of how ideas about biological evolution have been revised as Genetics contributions repeatedly tested them, and to ascertain the extent to which existing controversies (or "isms") are necessary, if not even useful; and to counterpose the importance of relativizing them, against the superior benefit of gaining a secure sense of the breadth of what is consensual and applicable.

In this communication, a review of this whole historical process is brought up, in order to establish time boundaries for the unifying content of Evolutionary Theory, through the recognition of three landmarks of conceptual development: the evolutionary works of Charles Darwin, Population Genetics, and the Neutral Theory. The currents of thought that have been causing division from the 19^th century to the present day are therefore excluded, among which the so-called «Modern Synthesis», propagandised from the 1940s onwards, assumes particular prominence. Finally, the evolutionary aspect of Ontogeny (also known as "evo-devo"), still problematic to integrate in the current Evolutionary Theory, is addressed. Ontogeny is a fundamental nexus for the understanding of Morphology and Physiology, and these in turn continue to be essential for Taxonomy, the latter implying an evolutionary explanation in the phylogenetic Natural System. Moreover, Ontogeny is the point of view for the concrete understanding, at the organismic level, of evolutionary processes. If on the one hand the Neutral Theory of Molecular Evolution has brought the fundamental support for an interpretation of macroevolutionary processes, the "how" of Evolution necessarily involves the establishment of unity and diversity mechanisms, still difficult to generalise, centred on Ontogeny.