Introduction

Abstract

A selective history of developmental and mechanical constrains on brain maturation and evolution includes both micro- and macroscopic theories. The general idea regarding the possible existence of overarching laws had its beginning in the early nineteenth century in the work of two prominent scientists; the French zoologist Étienne Geoffroy Saint-Hilaire (1772–1844) and the comparative anatomist George Cuvier (1769–1832). Their multiple debates in 1830 at the Royal Academy of Sciences in Paris examined whether animal structures could be explained by either function (Cuvier) or by morphological laws (Geoffroy). The question was summarized by the zoologist and historian of science E. R. Russell: “Is function the mechanical result of form, or is form merely the manifestation of function or activity? What is the essence of life – organization or activity?” (Russell 1916) The view espoused by Geoffrey, later known as the “doctrine of unity of composition”, argued that function was dependent on structure and that an archetype of a basic structural plan (Bauplan or body map) accounted for homologies across different animal phyla. The word homology was coined only after the Geoffroy-Cuvier debate by Owen to define “the same organ in different animals under every variety of form and function” (Medina 2007). Although, at the time, Geoffroy was judged to be on the losing side of the debate, modern discoveries of evolutionary conserved developmental control genes seemingly support his account of a construction plan that is shared by all bilateral animals (Hirth and Reichert 2007).