Climate determines which type of organisms live in a biome by influencing the characteristics of the habitat. Everything that falls under the climate category such as whether it rains a lot or not, the temperature all throughout the year, whether it snows or not, and others, influence the creation of a biome and of natural habitats. This is why you won't see lychens in warm places with polluted air, or you won't see polar bears outside of the polar regions.