It was just remarkable, with this evolutionary distance, that we should see such coherence in gene expression patterns. I was surprised how well everything lined up.
—Dr. Robert Waterston, co-senior author, Science (2025)
If one wanted to design an experiment to give natural selection the best possible chance of demonstrating its creative power, it would be hard to improve on the nematode worm.
Caenorhabditis elegans is about a millimeter long and consists of roughly 550 cells. It has a generation time of approximately 3.5 days. It produces hundreds of offspring per individual. Its populations are enormous. Its genome is compact—about 20,000 genes, comparable in number to ours but without the vast regulatory architecture that slows everything down in mammals. The worms experience significant selective pressure: most offspring die before reproducing, which means natural selection has plenty of raw material to work with. And critically, worms have essentially no generation overlap. When a new generation hatches, the old generation is dead or dying. Every generation represents a complete turnover of the gene pool. There is no drag, no cohort coexistence, no grandparents competing with grandchildren for resources.
In the notation of the Bio-Cycle Fixation Model, the selective turnover coefficient for C. elegans is approximately d = 1.0. Compare that to humans, where we have shown d ≈ 0.45. The worm is running the evolutionary engine at full throttle. No brakes, no friction, no generational overlap gumming up the works.
Now consider the timescale. C. elegans and its sister species C. briggsae diverged from a common ancestor approximately 20 million years ago. At 3.5 days per generation, that is roughly two billion generations. To put that in perspective, the entire history of the human lineage since the putative chimp-human divergence—six to seven million years at 29 years per generation—amounts to something like 220,000 generations. The worms have had nearly ten thousand times as many generations to diverge. Ten thousand times.
Two billion generations, running the evolutionary engine at maximum speed, with enormous populations, high fecundity, complete generational turnover, and all the raw material that natural selection could ask for. If there were ever a case where the neo-Darwinian mechanism should produce spectacular results, this is it.
But the data is reaching a conclusion that the researchers are not eager to draw. Two billion generations of evolution, operating under conditions more favorable than any large animal will ever experience, failed to produce any meaningful or functional divergence between two species. The mechanism ran at full speed for an incomprehensible span of time, and the result was the same worm.
This is not a philosophical objection to evolution. It is not an argument from personal incredulity or religious conviction. It is the straightforward empirical observation that the proposed mechanism, given every possible advantage, does not produce the results attributed to it. The creative power of natural selection, when measured rather than assumed, turns out to be approximately zero.
Two billion generations of nothing. A worm frozen in time. That’s what the data shows. And that’s exactly what Probability Zero predicted.