Colonies of cells. Each grows from a few cells to 64; a cell can mutate into a cheater, which divides three times as fast and gives the colony nothing. Each grown colony makes new colonies, more of them the more cooperators it has. See where the cheaters end up.
Cells a new colony starts from: one cell, or a fragment of 16. What a cooperator gives the colony: how many more new colonies it helps make.
Eight coloniesEight grown colonies of run 1, 64 cells each: dark a cheater, pale a cooperator.
Genes, cells, coloniesA cell's gene: cooperator or cheater. Cheaters divide faster (grey arrow); what a colony's cells became is what its new colonies are drawn from. What a cooperator gives the colony: a colony makes new colonies in proportion to 1 + that × its share of cooperators. Cells a new colony starts from: drawn from the grown colony. Grey arrows: fixed.
Target100 colonies, every cell a cooperator at the start. Go plays 150 generations, 8 times.The picture: what a hit looks like; the red box, where the thick line, the 8 runs' average, should end.The picture: what a hit looks like; the red box marks what has to match.
To finish
Hit the two targets. 0 of 2
Stage B is open.
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B
Finish Stage A to unlock this section.
Every cell does two jobs for its colony: keeping it alive (v) and making its offspring (b), traded off along a curve. A colony's fitness is its cells' average v times their average b. Two kinds of colony compete: generalists, every cell doing some of both, and specialists, some cells only germ and the rest only body. See which wins, and what each cell is worth on its own.
The trade-off, bowed in, straight or bowed out. Germ share: the share of a specialist colony's cells that are germ.
The trade-off and the two coloniesLeft: the trade-off between v and b; the dot, where every generalist cell sits (the best point for a generalist colony); the squares, a specialist colony's germ and body cells.Right: each colony's average v, average b, its fitness V × B, its cells' own fitness (v × b, averaged), and the difference, −cov(v, b).
Specialist colonies over timeThe share of the 100 colonies that are specialists; the 8 runs thin, their average thick.
Trade-off, cells, colonyThe trade-off sets each cell's v and b; the germ share, how a specialist colony divides its cells. A colony's fitness: V × B. 100 colonies, drawn each generation by fitness; 1 in 100 offspring colonies is the other kind. Grey arrows: fixed.
TargetHalf the colonies specialists at the start. Go plays 100 generations, 8 times.The picture: what a hit looks like; the red box, where the thick line should end.The picture: what a hit looks like; the red box marks what has to match.
To finish
Hit the two targets. 0 of 2
Stage C is open.
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C
Finish Stage B to unlock this section.
Stage A's colonies, starting from fragments of 16 cells, cooperators giving little. Two more ways a colony can deal with its cheaters. See what happens to the cheaters' gain inside colonies.
A germ line set aside: new colonies come only from the cells a colony started with, which do not divide, so a cheater made in its body never passes on. Policing: a share of new cheater cells killed as they appear.
Eight coloniesEight grown colonies of run 1, 64 cells each: dark a cheater.
Genes, cells, coloniesStage A's diagram, held at 16 cells and a small gift. A germ line set aside cuts the path from a colony's divisions to its new colonies; policing acts on the cheaters' divisions. Grey arrows: fixed.
TargetAs stage A. Go plays 150 generations, 8 times. Both targets also need the cheaters' gain inside colonies, averaged over the last 50 generations, at .005 or less a generation.The picture: what a hit looks like; the red box, where the thick line should end.The picture: what a hit looks like; the red box marks what has to match.
To finish
Hit the two targets. 0 of 2
That is the whole lesson.
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