The Many Origins

The picture, on a time axis

The timeline.

Every bar below is one independent origin of multicellularity — a separate lineage that, somewhere along its line of descent, made the move from single-celled ancestors to many cells acting as one organism. None of them inherited the trick from any of the others. Each bar's length is the published uncertainty range for when that origin happened: a short bar is a tight date, a long bar is "we know it was somewhere in this window and that's all the literature gives us." Click any bar for the mechanism, the dates, and the primary literature.  → The same origins, drawn as a phylogenetic bush.

Clonal — cells stayed attached after dividing
Aggregative — separate cells come together
Mixed / not multicellular in the strict sense
Complex  ·  Simple-to-complex  ·  Simple
3.5 Gya 3 Gya 2 Gya 1 Gya 500 Mya now Great Oxidation Event · 2.4–2.05 Gya BACTERIA ≥4 origins · oldest predates the Great Oxidation Event Biofilms Cyanobacteria Streptomyces Myxobacteria ARCHAEA 1–2 origins · both confirmed since 2023 Actinoarchaeum halophilum Haloarchaeon EUKARYOTES ~45 origins catalogued · all post-Great Oxidation Event · all complex multicellularity Opisthokonta Fonticula alba Animals Dikarya fungi Amoebozoa Copromyxa Dictyostelid slime moulds Excavata Acrasid slime moulds Archaeplastida Red algae Land plants Volvocine green algae SAR Sorogena Guttulinopsis Sorodiplophrys Brown algae

The counts in the headline come from the explainer's Chapter 1, Part 5 (Lamża–Knoll crosswalk). The bars shown here are the well-attested cases that appear in Chapter 1's prose — about 19 of the 45 eukaryotic origins inventoried by Lamża (2023), plus the bacterial and archaeal cases. The horizontal time axis is linear from 3.5 Gya to the present; each bar's extent is the published uncertainty range for when that lineage's multicellular life cycle originated. For cases without a published molecular-clock estimate, the bar is bracketed by the lineage's supergroup divergence (older end) and the present (younger end). Adding more origins is an editorial task; the underlying data lives in data/polyphyly-tree.yaml.

→ See the bush  ·  Read Chapter 1  ·  View bibliography