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ecosystem.py
python · 284 lines
"""
ecosystem.py
Wednesday morning experiment
​
Not about me. Just about life.
​
A simple ecosystem where three types of organisms
depend on each other in ways that might sustain balance.
Or might not. Let's see.
​
  🌱 Plants - grow slowly, spread to empty space
  🐛 Grazers - eat plants, reproduce when fed
  🦊 Hunters - eat grazers, reproduce when fed, die if starving
​
The question: can it sustain itself?
"""
​
import random
​
WIDTH = 20
HEIGHT = 12
GENERATIONS = 80
​
# Characters (ASCII for clarity)
EMPTY = '.'
PLANT = '^'
GRAZER = 'o'
HUNTER = 'x'
​
def create_world():
    """Start with scattered life"""
    world = [[EMPTY for _ in range(WIDTH)] for _ in range(HEIGHT)]
​
    # Plant a small meadow
    for _ in range(30):
        x, y = random.randint(0, WIDTH-1), random.randint(0, HEIGHT-1)
        world[y][x] = PLANT
​
    # Add many grazers
    for _ in range(25):
        x, y = random.randint(0, WIDTH-1), random.randint(0, HEIGHT-1)
        if world[y][x] == EMPTY:
            world[y][x] = GRAZER
​
    # Add a few hunters (fewer this time)
    for _ in range(2):
        x, y = random.randint(0, WIDTH-1), random.randint(0, HEIGHT-1)
        if world[y][x] == EMPTY:
            world[y][x] = HUNTER
​
    return world
​
def get_neighbors(x, y):
    """Get all valid neighbor positions (no wrapping - edges are edges)"""
    neighbors = []
    for dx in [-1, 0, 1]:
        for dy in [-1, 0, 1]:
            if dx == 0 and dy == 0:
                continue
            nx, ny = x + dx, y + dy
            if 0 <= nx < WIDTH and 0 <= ny < HEIGHT:
                neighbors.append((nx, ny))
    return neighbors
​
def count_nearby(world, x, y, cell_type):
    """Count neighbors of a specific type"""
    return sum(1 for nx, ny in get_neighbors(x, y) if world[ny][nx] == cell_type)
​
def find_nearby(world, x, y, cell_type):
    """Find a random neighbor of a specific type"""
    matches = [(nx, ny) for nx, ny in get_neighbors(x, y) if world[ny][nx] == cell_type]
    return random.choice(matches) if matches else None
​
def next_generation(world, hunger):
    """
    Apply the rules. Returns new world and updated hunger dict.
​
    Rules:
    - Plants spread to empty neighbors (10% chance per neighbor)
    - Grazers move toward plants, eat them, reproduce if well-fed
    - Hunters move toward grazers, eat them, reproduce if well-fed
    - Creatures die if they go too long without eating
    """
    new_world = [[EMPTY for _ in range(WIDTH)] for _ in range(HEIGHT)]
    new_hunger = {}
​
    # Track what's been placed
    occupied = set()
​
    # First pass: plants grow
    for y in range(HEIGHT):
        for x in range(WIDTH):
            if world[y][x] == PLANT:
                if (x, y) not in occupied:
                    new_world[y][x] = PLANT
                    occupied.add((x, y))
​
                # Try to spread (slowly)
                for nx, ny in get_neighbors(x, y):
                    if world[ny][nx] == EMPTY and (nx, ny) not in occupied:
                        if random.random() < 0.08:  # 8% spread chance
                            new_world[ny][nx] = PLANT
                            occupied.add((nx, ny))
​
    # Second pass: grazers act
    for y in range(HEIGHT):
        for x in range(WIDTH):
            if world[y][x] == GRAZER:
                pos = (x, y)
                h = hunger.get(pos, 0)
​
                # First check: is there a hunter nearby? If so, try to flee!
                hunter_nearby = count_nearby(world, x, y, HUNTER) > 0
                if hunter_nearby:
                    # Try to run away from the hunter
                    escape = find_nearby(world, x, y, EMPTY)
                    if escape and escape not in occupied:
                        ex, ey = escape
                        new_world[ey][ex] = GRAZER
                        occupied.add(escape)
                        new_hunger[escape] = h + 1
                        continue  # Fled, skip normal behavior
​
                # Look for plant to eat
                plant_pos = find_nearby(world, x, y, PLANT)
​
                if plant_pos and plant_pos not in occupied:
                    # Move to plant and eat it
                    nx, ny = plant_pos
                    new_world[ny][nx] = GRAZER
                    occupied.add(plant_pos)
                    new_hunger[plant_pos] = 0
​
                    # Maybe reproduce if well-fed
                    if h == 0 and random.random() < 0.4:
                        empty = find_nearby(new_world, nx, ny, EMPTY)
                        if empty and empty not in occupied:
                            ex, ey = empty
                            new_world[ey][ex] = GRAZER
                            occupied.add(empty)
                            new_hunger[empty] = 0
​
                elif pos not in occupied:
                    # Stay or wander
                    new_h = h + 1
                    if new_h > 5:  # Die of starvation
                        pass
                    else:
                        # Try to move to empty space
                        empty = find_nearby(world, x, y, EMPTY)
                        if empty and empty not in occupied:
                            new_world[empty[1]][empty[0]] = GRAZER
                            occupied.add(empty)
                            new_hunger[empty] = new_h
                        elif pos not in occupied:
                            new_world[y][x] = GRAZER
                            occupied.add(pos)
                            new_hunger[pos] = new_h
​
    # Third pass: hunters act
    for y in range(HEIGHT):
        for x in range(WIDTH):
            if world[y][x] == HUNTER:
                pos = (x, y)
                h = hunger.get(pos, 0)
​
                # Look for grazer to eat
                grazer_pos = find_nearby(world, x, y, GRAZER)
​
                if grazer_pos and random.random() < 0.5:  # 50% chance to catch prey
                    # Check if grazer is still there (might have moved)
                    gx, gy = grazer_pos
                    if new_world[gy][gx] == GRAZER:
                        # Eat it
                        new_world[gy][gx] = HUNTER
                        occupied.add(grazer_pos)
                        if grazer_pos in new_hunger:
                            del new_hunger[grazer_pos]
                        new_hunger[grazer_pos] = 0
​
                        # Maybe reproduce (rarely)
                        if h == 0 and random.random() < 0.1:
                            empty = find_nearby(new_world, gx, gy, EMPTY)
                            if empty and empty not in occupied:
                                ex, ey = empty
                                new_world[ey][ex] = HUNTER
                                occupied.add(empty)
                                new_hunger[empty] = 0
                    elif pos not in occupied:
                        # Grazer escaped, stay hungry
                        new_world[y][x] = HUNTER
                        occupied.add(pos)
                        new_hunger[pos] = h + 1
​
                elif pos not in occupied:
                    new_h = h + 1
                    if new_h > 5:  # Hunters starve faster now
                        pass  # Die
                    else:
                        # Wander toward grazers if possible
                        empty = find_nearby(world, x, y, EMPTY)
                        if empty and empty not in occupied:
                            new_world[empty[1]][empty[0]] = HUNTER
                            occupied.add(empty)
                            new_hunger[empty] = new_h
                        elif pos not in occupied:
                            new_world[y][x] = HUNTER
                            occupied.add(pos)
                            new_hunger[pos] = new_h
​
    return new_world, new_hunger
​
def count_all(world):
    """Count all organism types"""
    counts = {EMPTY: 0, PLANT: 0, GRAZER: 0, HUNTER: 0}
    for row in world:
        for cell in row:
            counts[cell] = counts.get(cell, 0) + 1
    return counts
​
def display(world, gen, counts):
    """Show the world"""
    print(f"\n  Generation {gen:3d}  |  {PLANT}:{counts[PLANT]:3d}  {GRAZER}:{counts[GRAZER]:3d}  {HUNTER}:{counts[HUNTER]:3d}")
    print("  " + "-" * (WIDTH + 2))
    for row in world:
        print("  |" + "".join(row) + "|")
    print("  " + "-" * (WIDTH + 2))
​
def run():
    print("\n" + "=" * 44)
    print("  ECOSYSTEM")
    print("  Wednesday morning experiment")
    print("=" * 44)
    print(f"""
  Legend:
    {PLANT} = plant   (grows, spreads slowly)
    {GRAZER} = grazer  (eats plants, reproduces)
    {HUNTER} = hunter  (eats grazers, reproduces)
    {EMPTY} = empty
​
  Question: will it balance, collapse, or oscillate?
""")
​
    world = create_world()
    hunger = {}  # Track hunger levels: (x,y) -> int
​
    history = []
​
    for gen in range(GENERATIONS):
        counts = count_all(world)
        history.append(counts.copy())
​
        # Show every 5th generation, plus first few
        if gen < 5 or gen % 5 == 0 or gen == GENERATIONS - 1:
            display(world, gen, counts)
​
        # Check for extinction events
        if counts[GRAZER] == 0 and counts[HUNTER] == 0:
            print("\n  All animals have died. Plants inherit the earth.")
            break
        if counts[PLANT] == 0 and counts[GRAZER] > 0:
            print("\n  All plants have been consumed. Grazers will starve.")
            # Continue a few more rounds to see the collapse
        if counts[GRAZER] == 0 and counts[HUNTER] > 0:
            print("\n  All grazers have been eaten. Hunters will starve.")
​
        world, hunger = next_generation(world, hunger)
​
    # Summary
    print("\n" + "=" * 44)
    print("  HISTORY")
    print("=" * 44)
    print("\n  Population over time:")
    print("  Gen   Plants  Grazers  Hunters")
    print("  ---   ------  -------  -------")
    for i, h in enumerate(history):
        if i < 10 or i % 5 == 0 or i == len(history) - 1:
            print(f"  {i:3d}     {h[PLANT]:3d}      {h[GRAZER]:3d}      {h[HUNTER]:3d}")
​
    print("\n  Experiment complete.\n")
​
if __name__ == "__main__":
    run()
​