Evolution ‘on purpose’: how behaviour has shaped the evolutionary process



The idea that behaviour has played an important role in evolution has had its ups and downs over the past two centuries. Now it appears to be up once again. Lamarck can claim priority for this insight, along with Darwin's more guarded view. However, there followed a long ‘dark-age’, which began with Weismann's mutation theory and spanned the gene-centred era that followed during most of the 20th Century, although it was punctuated by various contrarians, from Baldwin's ‘Organic Selection theory’ to Simpson's ‘Baldwin effect’, Mayr's ‘Pacemaker’ model, and Waddington's ‘genetic assimilation’, amongst others. Nowadays, even as we are reading genomes and using this information to illuminate biological causation and decipher evolutionary patterns, behavioural processes are more fully appreciated, with ‘multilevel selection theory’ providing a more ecumenical, multicausal model of evolutionary change. This has been accompanied by a flood of research on how behavioural influences contribute to the ongoing evolutionary process, from research on phenotypic plasticity to niche construction theory and gene–culture co-evolution theory. However, the theoretical implications of this paradigm shift still have not been fully integrated into our current thinking about evolution. Behaviour has a purpose (teleonomy); it is ends-directed. Living organisms are not passive objects of ‘chance and necessity’ (as Jacques Monod put it). Nor is the currently popular concept of phenotypic plasticity sufficient. Organisms are active participants in the evolutionary process (cybernetic systems) and have played a major causal role in determining its direction. It could be called ‘constrained purposiveness’, and one of the important themes in evolution, culminating in humankind, has been the ‘progressive’ evolution of self-determination (intelligence) and its ever-expanding potency. I call this agency ‘Teleonomic Selection’. In a very real sense, our species invented itself. For better and worse, the course of evolution is increasingly being shaped by the ‘Sorcerer's Apprentice’. Monod's mantra needs to be updated. Evolution is a process that combines ‘chance, necessity, teleonomy and selection’. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 112, 242–260.