A user in Second Life has created a virtual ecosystem within the game!

While taking a break from the UK game industry to raise her child, a programmer created a self-contained ecology on a Second Life island, with numerous species and natural phenomenon that must work together to keep the system function: clouds rain on the land, nourishing the plants (which also respond to sunlight), bees spread pollen to help the plants reproduce, birds eat seeds to keep the plants from growing out of control, and so on.