How do different environments support varieties of organisms?

Each organism has adaptations for its specific environment. Those adaptations will allow it to survive easily in one environment, but may make it impossible for that organism to survive in another environment. For example, a polar bear can live in the Arctic, but it would die of heat stroke within hours if you took it the Sahara Desert. Because each environment supports different adaptations, different organisms live in each environment, and each environment adds to the variety of organisms on Earth.