What defines a biome and where each occurs
A biome is a large region characterized by its climate, dominant vegetation, and the animal communities adapted to it. The major terrestrial biomes include tundra, taiga (boreal forest), temperate deciduous forest, grassland, desert, savanna, and tropical rainforest. Their global positions are governed largely by temperature and precipitation, which in turn follow latitude and the patterns of atmospheric circulation.
Cold biomes such as tundra and taiga dominate high latitudes, deserts cluster around 30 degrees latitude where descending dry air prevails, and tropical rainforests concentrate near the equator where warmth and heavy rainfall coincide.
Primary productivity across biomes
Net primary productivity, the rate at which plants convert sunlight into biomass, varies enormously between biomes. Tropical rainforests are among the most productive terrestrial systems because of abundant light, warmth, and water, while deserts and tundra are among the least productive due to water or temperature limits.
These differences in productivity shape how much carbon each biome stores and how many organisms it can support, making biome distribution central to understanding global ecology and the carbon cycle.