The evolution of multicellularity

Assembled from 16 blocks · 2 evidence · 11 related

1. Story
2. Not one event but a repeated one, and that repetition is the most important fact about it. Simple multicellularity — cells that stay attached after division — has arisen independently dozens of times across bacteria, algae, fungi, plants and animals, which tells us the step is easy. Complex multicellularity, meaning three-dimensional bodies with differentiated cell types, regulated development and cells that cannot survive alone, has arisen far fewer times: animals, fungi, land plants, red algae, brown algae and a small number of others. Every one of those is a eukaryote. The hard part is not sticking together but the evolution of an enforceable division of labour, because a cell that abandons its own reproduction to build somebody else's body is vulnerable to cheating, and the standard solution is a single-cell bottleneck each generation that keeps the whole body genetically identical. The oldest taxonomically resolved case is the red alga Bangiomorpha, which also shows differentiated holdfast cells and spores; a far older and much-argued candidate is the 2.1 billion-year-old Francevillian biota of Gabon.
3. Knowledge
4. Endosymbiosis and the eukaryotic cell
5. The evolution of multicellularity
6. Connections
7. Endosymbiosis and the eukaryotic cell
8. Bangiomorpha pubescens
9. Francevillian Basin, Gabon
10. Ediacara Hills, Flinders Ranges
11. Centimetre-scale structures reported from 2.1 Ga Gabonese shales
12. The evolution of multicellularity
13. The Great Oxidation Event
14. Evidence
15. Supports the description of Bangiomorpha, its assignment to the red algae, its differentiated holdfast and the interpretation of its reproductive structures as evidence of sex. Deliberately cited without page numbers, which were not confirmed. V55 verification basis: this session had no network access to any source — WebFetch was egress-blocked and the WebSearch budget was exhausted — so the cited work was not retrieved and its pagination was not re-checked.
16. Supports the description of the Francevillian structures and their interpretation as colonial organisms. The interpretation is disputed; no rebuttal is cited here. V55 verification basis: this session had no network access to any source — WebFetch was egress-blocked and the WebSearch budget was exhausted — so the cited work was not retrieved and its pagination was not re-checked. Volume and page range are quoted from standing knowledge and were not re-checked.