I haven’t been blogging much lately, and here’s one of the reasons: Peter Conlin, Will Ratcliff, and I have been editing a book on the evolution of multicellularity, which the publisher says will come out in late March, 2022. It’s available for preorder now, at a 20% discount.

The Evolution of Multicellularity, cover art by Pedro Márquez-Zacarías

Our goal was to produce a single resource that could serve as a starting point for readers interested in the evolution of multicellularity, a reference for researchers on the subject, and a jumping-off point to stimulate future research. We hope it will provide a sufficient overview so that a reader unfamiliar with the relevant literature will come away with an understanding of the major issues. What types of multicellular organisms exist? What are their evolutionary relationships? What processes led to their origins and subsequent evolution? In what conceptual frameworks can their evolution be understood? What questions remain to be answered?

We invited some of the some of the most influential authors in the field, and to our delight and amazement, nearly all accepted. The results have far exceeded our expectations. The chapters cover their respective topics exceptionally well, combining broad overviews with compelling examples and historical context with recent discoveries.

Aside from the intro and concluding chapters written by the three of us, the book is organized into four sections: Theory and Philosophy, Aggregative Multicellularity, Clonal Multicellularity, Life Cycles and Development. Sections 2 and 3 each begin with a chapter on the phylogenetic distribution of aggregative and clonal multicellularity, respectively, followed by chapters on the formation, maintenance, and transformation of multicellular groups (this organization was inspired by Andrew F. G. Bourke’s The Principles of Social Evolution).

Will’s megathread on Twitter does a good job describing the chapters, but here’s a listing for convenience:

• Foreword (Andrew H. Knoll)
• Chapter 1: Introduction: the evolution of multicellularity in context (Matthew D. Herron, Peter L. Conlin, and William C. Ratcliff)
• Section 1: Theory and Philosophy
  • Chapter 2: Getting at the basics of multicellularity (Maureen O’Malley)
  • Chapter 3: Multi-level selection of the individual organism (Richard E. Michod)
  • Chapter 4: Life cycles as a central organizing theme for studying multicellularity (Merlijn Staps, Jordi van Gestel, and Corina E. Tarnita)
• Section 2: Aggregative Multicellularity
  • Chapter 5: Eukaryote aggregative multicellularity – phylogenetic distribution and a case study of its proximate and ultimate cause in Dictyostelia (Pauline Schaap)
  • Chapter 6: Group formation: On the evolution of aggregative multicellularity (Marco La Fortezza, Kaitlin A. Schaal, and Gregory J. Velicer)
  • Chapter 7: Group maintenance in aggregative multicellularity (Israt Jahan, Tyler Larsen, Joan Strassmann, and David Queller)
  • Chapter 8: Group transformation: fruiting body and stalk formation (Cathleen Broersma and Elizabeth Ostrowski)
• Section 3: Clonal Multicellularity
  • Chapter 9: Phylogenetics of clonal multicellularity (Michelle M. Leger and Iñaki Ruiz-Trillo)
  • Chapter 10: Group formation: hypotheses for the evolution of clonal multicellularity (Stefania Kapsetaki and Roberta M. Fisher)
  • Chapter 11: Group maintenance in clonal multicellularity: Controlling intra-organismal evolution (Aurora M. Nedelcu and Alexander N. May)
  • Chapter 12: Group transformation: life history tradeoffs, division of labor and evolutionary transitions in individuality (Guilhem Doulcier, Katrin Hammerschmidt, and Pierrick Bourrat)
• Section 4: Life Cycles and Development
  • Chapter 13: The single-celled ancestors of animals: a history of hypotheses (Thibaut Brunet and Nicole King)
  • Chapter 14: Convergent evolution of complex multicellularity in fungi (László G. Nagy)
  • Chapter 15: Genetic and developmental mechanisms of cellular differentiation in algae (Susana M Coelho and Mark Cock)
  • Chapter 16: The evolution of complex multicellularity in streptophytes (Liam N. Briginshaw and John L. Bowman)
  • Chapter 17: Multi-species multicellular life cycles (Rebecka Andersson, Hanna Isaksson, and Eric Libby)
• Chapter 18: Conclusion: The future of multicellularity research (William C. Ratcliff, Peter L. Conlin, and Matthew D. Herron)