International Lectures on Nature and Human Ecology

Telmo Pievani
Wad, the evolutionist: the relevance of Wad's breadth of interests 40 years later

According to Jonathan Slack (2002), Conrad H. Waddington could be defined as "the last Renaissance biologist", for his breadth of interests and his anticipatory thinking. In my talk, I used a metaphor proposed by Wad's friend Gregory Bateson: the pattern that connects.
Wad's thinking is a pattern that connects. Namely, I discussed six connections that summarize Wad's scientific career:
1) Embryology and genetics (strong integration of developmental processes under genetic control);
2) Genes to genes (large networks of genes interact in order to shape cell differentiation and developmental processes; interactionism);
3) Gene regulatory products and developmental phenotype (epigenetic landscape; canalizations of development; competence);
4) Environments and organisms (genetic assimilation, as a multi-generational, selective conversion of acquired characters into heritable characters);
5) Development and evolution (the evolution of organisms seen as evolution of developmental systems, like in Evo-Devo today);
6) Organisms and niches (the concept of "exploitive systems", and the idea that environmental stresses and selective pressures depend also on the activities of organisms in their habitats, like in Niche Construction models today).

I analyzed each connection in some details, stressing several points of Wad's relevance 40 years later, according to current experimental evidence. In the second part of my talk I discussed the evolutionary implications of Wad's six connections, shaping his "Post-Neo-Darwinian" view on evolution: a revised, expanded Neo-Darwinism against the gene-centered, athomistic and pan-selectionist approach of the Modern Synthesis, anticipating what we call today "Extended Evolutionary Synthesis".

I discussed the four «systems» of his Post-Neo-Darwinian theory of evolution (genetic system, natural selective system, epigenetic system, exploitive system), focusing on the relationships between the genealogical side of evolution (random genetic variation; differential reproduction) and the ecological-interactive side of evolution (non-random phenotypic variation; ecological survival of phenotypes as developmental systems). Summing up, I proposed to see Wad' thinking as a seminal work for the shift towards a new, extended Darwinian "scientific research programme" (following Imre Lakatos' terminology), able to give the deserved theoretical role to evolutionary factors such as developmental bias, plasticity, and niche construction.

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