BioSphere — Evolving Creature Simulation

An in-depth, browser-based ecosystem where creatures with neural-net brains and heritable genetic traits co-evolve under natural selection. Watch life emerge, sculpt the environment, inspect any creature's brain, and fast-forward through generations.

This grew out of the original Java UnitGame prototype (still in src/). The full simulation lives in web/ and runs entirely in the browser — no build step.

Run it

cd web
python3 -m http.server 8777
# open http://localhost:8777

Or just open web/index.html directly in a browser.

What's simulated

• Dual-layer evolution — each creature has a feed-forward neural network (brain) and a genome of physical traits (size, speed, vision, field-of-view, metabolism, diet, aggression, fertility, color, mutability). Both mutate and cross over on reproduction.
• Full ecology — procedurally generated terrain (grass, water, rock, dirt), plants that regrow with daylight, herbivores, carnivores, and corpses that decay back into the soil to fertilize new growth.
• Emergent behavior — food-seeking, fleeing, hunting, and herding arise on their own from selection; nothing is hard-coded.
• Day/night cycle affecting vision range and plant growth.
• Seasons & disasters — a Spring→Winter cycle modulates food and metabolism, and catastrophes (drought, superbloom, plague, meteor impacts that crater the terrain) strike randomly or on demand, driving real selection.
• Species clustering — live genetic clustering labels emergent species/lineages.
• Phylogenetic tree — a time-based lineage tree records when species branch from an ancestor (tracked through real parent→child ancestry), how big each got, and when they go extinct. Click a living lineage to inspect a member; hover for details.
• Scenario presets — generate tuned worlds: Balanced, Eden (lush & peaceful), Predator pressure, Archipelago, or Harsh desert.

What you can do

• Watch — pan (drag), zoom (scroll), a mini-map for navigation, adjustable speed, color creatures by species / diet / energy / generation, toggle vision cones, and heatmap overlays (where creatures live, where they die, food pressure).
• Edit the environment (god mode) — paint grass/water/rock/dirt/food, drop herbivores or carnivores, remove creatures, adjustable brush.
• Tune the world live — plant growth, energy drain, mutation rate, turn agility, day/night, seasons, disasters, auto-respawn floor; trigger disasters manually.
• Train & analyze — live charts (population, plant cover, births/deaths, average traits, gene-distribution histograms), a phylogenetic lineage tree + Muller plot of who dominates over time, a chronicle narrating major events, a Hall of Fame of all-time champion creatures (re-spawnable as clones), inspect any creature's brain with live activations and gene bars, manually breed favorites, fast-forward many generations headless, and save/load whole worlds to JSON.

Keyboard

Space play/pause · . step · f fast-forward · v toggle vision cones

Code layout (web/js/)

File	Responsibility
utils.js	RNG, math, vector & color helpers
nn.js	tiny feed-forward neural network (brain)
genome.js	heritable trait genome + mutation/crossover
creature.js	agent: sensing, brain, energy, eating, reproduction
world.js	terrain, plants, corpses, day/night, spatial hash
simulation.js	tick loop, stats history, species clustering, save/load
renderer.js	canvas rendering, pan/zoom, selection
charts.js	analytics charts + neural-net visualizer
ui.js	inspector, species list, gene bars, toasts
main.js	game loop + all input/control wiring

For power users, window.BioSphere exposes the live sim and renderer in the dev console.