When food runs out, tens of thousands of lone amoebae — each a separate single-celled creature — stream together by chemical pulse into one body: a crawling slug, then a stalk that sacrifices a fifth of its cells so the rest can rise as spores. A many-celled animal that is really a society, voting with chemistry to become one.
The Four Natures
each piece emerges by one of four natures
The Idea
the three-beat story
Dictyostelium discoideum lives in the soil as thousands of separate amoebae, each a complete single-celled organism that crawls, hunts bacteria, and divides on its own. As long as there is food, they ignore each other entirely.
When the food runs out, a few cells begin pulsing a signal — cyclic AMP — in rhythmic waves. The others relay the pulse and crawl toward its source, streaming inward in spiraling rivers until tens of thousands have piled into a single mound. A multicellular body, summoned from loners by chemistry.
The mound becomes a crawling 'slug,' then stands up as a fruiting body: a slender stalk holding a ball of spores aloft. But the stalk is made of cells — about a fifth of them — that die to lift the others to where they can disperse. Altruism, and the cheaters who dodge it, all in a puddle of amoebae.
The Gathering
starved amoebae relay pulses of cAMP; each cell crawls up the gradient toward the signal, streaming inward until thousands pile into one mound. Click to drop a new signaling center. An illustration of cAMP-driven aggregation, NOT a developmental simulation.
The Reckoning
the thread, and the honesty about it
A Society That Becomes a Body
the thread
- The starkest case of the collective made literal: free-living single cells that assemble into one organism, and back again.
- >Cousin and contrast to the slime mold (Physarum is ONE cell with many nuclei; Dicty is MANY cells that gather) — and kin to quorum sensing and the ant colony's superorganism.
How It Decides
the mechanism, honestly
- The aggregation is self-organizing: cAMP pulses relayed cell to cell produce the spiraling waves, a textbook excitable medium — the same math as a heartbeat or a chemical clock.
- The stalk's sacrifice is real altruism with a real tension: 'cheater' strains that take the spore fate and skip the stalk exist, and the system polices them. Described as the science reports it.
Render, Not Invent
sourced
- Summarized from the public record; John Tyler Bonner (d. 2019), who built the field, is minted in memoriam; living researchers (Strassmann & Queller, Shaulsky, Gerisch-era successors) are CITED, not minted.
- Emergents are stages, signals, and concepts. The aggregation below is an illustration of cAMP-driven streaming, not a developmental simulation.
The Roster
the cells, concepts, and pioneers as ACI .agents — each a birth certificate & a nature (11)
