Prof. Dr. Jacobus "Koos" Boomsma, UCPH, Denmark

"Kin-selection and the Major Transitions in Evolution"

The term Major Transition in Evolution (MTE) was coined in the 1990s without offering a universal definition or a unifying hypothesis for how MTEs might have originated. Rather, MTEs were suggested to merely emerge by chance when higher-level selection somehow became strong enough to turn loose societies into integrated organismal units. In this seminar I will summarize key elements of my 2022 book: Domains and Major Transitions of Social Evolution - Paperback - Koos Boomsma - Oxford University Press (oup.com). In particular, I will develop the following points to argue that the levels-of-selection view of MTEs is mistaken and should be replaced by an inclusive fitness theory (IFT) perspective that generates testable predictions: 1. There are four discrete levels in life’s organizational complexity: the prokaryote cell, the eukaryote cell, the somatic multicellular body, and the caste-differentiated colony. 2. Individuals within these four levels, comprising a single cell, a single body or a single colony, are fundamentally closed in terms of genetic information, at least when they originate. 3. Open societies have independently evolved within each of these four domains but such societies were never ancestral to higher-level organismality, i.e. they never produced MTEs. 4. Decades of research have shown that George Price’s statistical formalization of Hamilton’s rule is both necessary and sufficient to explain condition-dependent cooperation in open societies. 5. However, there is a complementary application of IFT to explain the origins of all MTEs towards obligate, unconditional cooperation in an irreversible higher level of closed organismality. 6. This conjectural approach partitions Hamilton’s rule (brx > cro) into a separate necessary condition (rx= ro) and an additionally required sufficiency condition (b > c) for any MTE origin. 7. New levels of closure around a lifetime committed pair of symbionts, gametes or parents appear to allways maximize offspring relatedness independent of gene-pool identity. 8. As far as I am aware, all available comparative data are consistent with my kin-selection theory for the origins of MTEs, but the conjecture deserves to be criticized and tested in Popper’s spirit. 9. My analysis challenges the idea that conditional cooperation (altruism/mutualism) can evolve into obligate cooperation as an anthropomorphic wishful-thinking projection upon the rest of nature. 10. Much of my logic was intuitively captured by Darwin (1859), all the way up to Williams (1966), but sociobiology’s thinking in gradients from microbes to men muddled conceptual transparency. My book emphasizes the fundamental importance of the neo-Darwinian ‘gene’s eye view’ of adaptive evolution, as first developed in the 1960s by Hamilton and Williams building on Tinbergen’s four kinds of complementary questions for understanding any question in organismal biology. In the final chapter I outline how and why the Human MTE is incomparable to any other MTE in the history of life.