About Drift King

Breed, herd and watch allele frequencies wander across generations in this free online genetic drift game about evolution's random side.

Drift King is a free online genetic drift game where you steward an island herd of Driftites through evolution you cannot steer. Every creature carries two copies of a color gene, Ember or Tide. Each generation the herd resamples its alleles by lottery, the Wright-Fisher model at the heart of population genetics. You never pick a winner. You only shape the arena: food raises carrying capacity, storms crash the population, rafts seed founder colonies, migrants carry in fresh genes and mate-preference fads ignite runaway sexual selection.

Every mechanic maps to real population genetics. Genetic drift is strongest in small herds because sampling error scales with effective population size Ne, which is why bottleneck storms and 4-founder colonies make the gene pool lurch while a fat, well-fed herd barely trembles. Predators eat the common morph, mirroring apostatic selection where rare looks survive better. Mutation spores are the only force that can return an allele once drift has fixed the other. The health bar tracks heterozygosity, the 2pq diversity measure that conservation biologists watch in endangered species.

This matters because drift is not a rounding error, it is how real species evolve and crash. Northern elephant seals fell to a few dozen individuals and still carry the scar of lost diversity. Cheetahs are so genetically uniform they accept skin grafts from strangers. Island populations founded by a handful of colonists, like the achromatopsia carriers of Pingelap, keep a founder's genetic fingerprint for centuries. The same math decides whether a reintroduced wolf pack or a zoo breeding program keeps enough variation to survive.

Key Science Concepts

• Genetic drift and the Wright-Fisher model
• Effective population size Ne and heterozygosity decay
• Population bottlenecks and the founder effect
• Gene flow, migration and translocation
• Fisherian runaway sexual selection
• Negative frequency-dependent selection and mutation

What You'll Learn

• Explain why small populations drift faster than large ones
• Predict what bottlenecks and founders do to allele frequencies
• Distinguish drift from selection and mutation
• Connect runaway mate preference to real ornament evolution

Grade Level: Middle School, High School

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How to play

1. Watch the Gene Pool Every few seconds a new generation resamples alleles at random. The pool bar below swings by pure luck, no selection needed.
2. Feed to Grow Tap berries to raise carrying capacity. Big herds drift gently, tiny herds lurch.
3. Weather Storms Swat bottleneck storms or let them cull the herd. Survive a cull with both alleles for a Drift Survivor bonus.
4. Seed a Colony Tap a raft to send 4 founders to an islet. Their allele mix drifts wildly, then merges back home.
5. Ride the Fad Tap a feather fad and mates chase the rare look. The runaway spiral scores big but risks fixation.
6. Rescue Diversity If an allele fixes, tap migrants or a mutation spore to bring it back. The health gauge fires an emergency translocation.

Frequently asked questions

Is Drift King free to play?

Yes. Drift King is completely free to play in your browser. There is no download, install or account needed.

What grade level is Drift King for?

Drift King is designed for Middle School, High School students and works well as a classroom activity or homework.

Does Drift King work on phones and tablets?

Yes. Drift King runs in any modern browser on desktop computers, Chromebooks, tablets and phones in landscape mode.

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