The Points-of-no-Return Ratchet to Higher Levels of Organismal Complexity
I plan to continue exploring the boundaries of the lifetime commitment principle that I developed in previous review papers. My approach elaborates that the origins of major transitions to obligate multicellularity and colonial superorganismality can always be captured in necessary and sufficient conditions that emerge from Hamilton's rule. The lifetime commitment principle, also known as the lifetime monogamy principle for explaining obligate reproductive division of labor in the social insects, appears to have fundamental consequences for how we understand the progression of life's complexity over evolutionary time. Major transitions to higher levels of organic complexity are a ratchet-like process. When the ratchet will click cannot be predicted, but if it does it will produce a major transition that is irreversible. Secondary reductions of complexity may well happen, but genome-wide rewiring of developmental pathways makes reversals to ancestral lower-level complexity impossible. In this view, "coming together" in same-generation chimeras is a fundamentally different starting condition from "staying together" across generations. Only staying together can lead to permanent higher-level adaptive states of complexity via family selection, whereas (non-family) group selection is unable to achieve that for "coming together". George C. Williams rightly acknowledged the fundamental difference between family selection and group selection more than 50 years ago, but the later sociobiology tradition lost sight of this distinction that was in fact also intuitively clear to Darwin, Weismann, and the key architects of the Modern Synthesis of evolutionary biology. Capturing the lifetime commitment principle in verbal, diagrammatic and simple mathematical terms is an important overarching objective, both for my book project and for additional studies to be pursued during my stay at the Wissenschaftskolleg.
Boomsma, J. J. and R. Gawne (2018). "Superorganismality and caste differentiation as points of no return: how the major evolutionary transitions were lost in translation. Biological Reviews 93: 28-54.
Smith, S. M., D. S. Kent, J. J. Boomsma, and A. J. Stow (2018). "Lifetime monogamous sperm storage and permanent worker sterility in a long-lived ambrosia beetle." Nature Ecology and Evolution. doi: 10.1038/s41559-018-0533-3.
Boomsma, J. J. (2016). "Fifty years of illumination about the natural levels of adaptation." Current Biology 26, R1250-R1255.
Boomsma, J. J. (2013). "Beyond promiscuity: Mate choice commitments in social breeding." Philosophical Transactions of the Royal Society London 368: 20120050.