What defines a biome?

A biome is best defined as a collection of ecosystems that share similar climatic conditions. This means that biomes are characterized not just by individual ecosystems, but rather by the broader environmental factors—such as temperature, precipitation, and the types of flora and fauna—that unify various ecosystems in a particular region.

For example, the temperate forest biome includes multiple ecosystems with varying species compositions, yet all are adapted to similar seasonal climates of moderate temperatures and adequate rainfall. The classification into biomes helps ecologists understand patterns of biodiversity and ecological characteristics associated with particular climatic conditions.

In contrast, the other options focus on narrower concepts. The geographic distribution of animal species is only one aspect of a biome and doesn’t encompass the interconnectedness of ecosystems. Similarly, defining a biome as a single ecosystem overlooks the diversity and complexity found within a biome. Lastly, while a biome does contain a diverse range of habitats, the defining factor is indeed the shared climate among those ecosystems rather than just the range of habitats.