Aetheris simulates a world with evolving continents, changing weather and terrain, and seasons. Plant life grows and adapts to changing conditions and competition from other plants. You can change settings that control the geography and ecology of the world.
The world has a subtle ring that helps orient you as you grab and turn the world (you are actually changing your viewpoint, not spinning the planet).
Plants emerge from seeds and grow in patterns determined by their genetic code and responding to their environment and their neighbors. As they get older, plants can divide into genetically related individuals, or they can spread through spores (if you allow it).
Each plant prefers a certain type of terrain — forest, grassland, desert, ice or sea. A plant will live longest in its preferred terrain, but can survive for a while in other terrains. A plant can generalize to live in multiple terrains, but it won't live as long as a plant that specializes for particular conditions. A strongly specialized plant has strongly colored leaves, while a generalist's colors are more muted.
The simulator has three clocks. Each day is one rotation of the planet. This clock never changes, because otherwise it would be hard to see details of the world. Each year is one orbit around the world's star. This clock can run faster so you can see the yearly expansion and contraction of ice sheets at the poles and on mountain tops. The third clock is a geological clock. You can dramatically speed up this clock so you can see the coastlines and habitats change quickly. Plants race each other to adapt as quickly as they can (or die).
The settings page has a link you can copy to share your world and its settings. A link always starts its world from the beginning, so leave it running to reach what you were looking at. And if you changed settings part way through the simulation, it will not even do that — what you were watching took a path that a list of settings cannot describe. The panel tells you which of the two you have, underneath the link.