Cell size matters: a unifying theory across the tree of life
Marcin Czarnołęski, Wilco C. E. P. Verberk
Abstract
Cell size shapes how organisms interact with their environment, yet our understanding of these effects remains fragmented. We synthesise these effects into a Theory of Optimal Cell Size (TOCS), predicting that the size of single-cell organisms, as well as the number and size of cells in multicellular organisms, is subject to strong selection. At the heart of TOCS lies a trade-off between power and energy conservation: cell size acts as a 'double-edged sword', influencing both resource acquisition and maintenance costs. Major evolutionary transitions across the tree of life are connected with innovations in cellular organisation. A unified framework for cell size adaptation is essential for revealing the fundamental principles governing the ecology and evolution of life.