Biomes: Life Zones of the Earth

A biome is a large region defined by its climate and the plants and animals adapted to it, such as tropical rainforest, savanna, desert, temperate grassland, temperate forest, taiga and tundra. Climate is the main driver: temperature and rainfall decide which plants can grow, and plants shape which animals can live there. Tropical rainforests receive heavy rain all year and hold an extraordinary share of Earth's species.

The taiga, a belt of coniferous forest across Canada, Scandinavia and Russia, is the largest land biome, while the tundra beyond it has permanently frozen ground called permafrost. Biomes also reflect human activity: grasslands have been widely converted to farmland, and forests cleared for crops and cattle. Studying biomes helps explain why some regions are fragile, why biodiversity is unevenly spread, and how shifting climate zones may move the boundaries between them.