A biome basically represents an ecological community categorized by its physical characteristics such as soil, its climate and the life it supports. While Earth can be considered as one biome, it's normally subdivided into additional biomes.
Scientists separate biomes into two distinct classifications: aquatic and terrestrial. The largest biome on Earth is the aquatic one, as water covers 75 percent of the globe. Further scientific cataloguing leads to multiple eco-regions across the globe.