The virtual world: the terrain
The terrain is textured with either a base ‘grass’ texture, or a ‘subwater’ texture. It may be overlaid with a secondary texture if it has a ‘plant’ on it.
Its textures are modulated by a base colour …
Its base colour is dependant on its temperature,
which is a function of its distance from the equator,
and any effects due to its plant occupant.
This should create arctic and desert regions in the world, to which the inhabitants (plant and creature) can adapt.