The World's Major Biomes

A biome is a massive area of the world that shares a similar climate (weather patterns over a long time) and specific types of plants and animals. People often confuse biomes with ecosystems, but there is a big difference in size! Think of an ecosystem as a single backyard pond. A biome, however, would be all the ponds, forests, and fields across an entire continent that have the same weather. It is like the difference between your specific bedroom (ecosystem) and your entire neighborhood (biome). The plants and animals in a biome have special adaptations to help them survive in that specific environment.

Scientists generally group the world into five main categories. First is the Aquatic biome, which covers about $75\%$ of Earth's surface and includes oceans and lakes. Second is the Desert, which is defined by being very dry. Third is the Forest, filled with trees and diverse life. Fourth is the Grassland, where grasses dominate because there isn't enough rain for thick forests. Finally, there is the Tundra, the coldest biome where the ground is often frozen year-round. Each of these biomes is like a unique 'room' on Earth with its own temperature and 'decorations' (plants).

Why isn't the whole world just one big jungle? The type of biome that forms in a location depends on two main 'ingredients': Temperature ($T$) and Precipitation ($P$), which is rain or snow.

We can think of it like a simple formula. If $T$ is high (hot) and $P$ is high (wet), you get a Rainforest. If $T$ is high but $P$ is very low (dry), you get a Desert. If $T$ is very low, it doesn't matter how much it rains; you will likely have a Tundra. These two factors decide what kind of plants can grow, and the plants decide what kind of animals can live there.