concept

Biome

A major climate-shaped kind of ecosystem - tropical rainforest, desert, temperate forest, grassland, tundra - and the communities of life within it. The ecologist Robert Whittaker showed that just two numbers, mean annual temperature and mean annual precipitation, sort nearly every community into its box. Because atmospheric circulation decides where a world is warm-and-wet or dry-and-cold, it also draws the map of biomes on any world.