A weird mathematical 'glitch' explains why there's a specific size of green algae that just doesn't exist in nature.
arXiv · March 17, 2026 · 2603.15171
The Takeaway
During development, some algae embryos must literally turn themselves inside out like a sock to survive. Researchers discovered a mechanical limit where this process becomes physically impossible for colonies of exactly 256 cells, explaining a mysterious evolutionary gap between tiny and giant species.
From the abstract
The processes of morphogenesis that give rise to the shapes of organs and organisms during development are often driven by mechanical instabilities. Can such mechanical bifurcations also drive or constrain the evolution of these processes in the first place? We discover an instance of these constraints in the green algae of the family Volvocaceae. During their development, their bowl-shaped embryonic cell sheet turns itself inside out. This inversion is driven by a simple wave of cell wedging in