Habitat is the environment, including physical, climatic and biotic conditions, where an organism naturally lives. Every species has certain habitat requirements in order to survive and thrive; some require very specific conditions and can only survive in limited geographical areas while others are tolerant of a wide range of variations. An example of the former is the giant panda, which requires large bamboo forests on cool, wet, high mountainsides; an example of the latter is the rat.
Habitats tend to change over time, gradually or suddenly. This can be due to natural events or processes, such as changes in climate, volcanic eruptions, wildfires, changes in the course of a river, or the entry of invasive species. But it has also become increasingly due to human activity, including deforestation, the draining of wetlands, hunting, the expansion of agriculture, urbanization, and the introduction of alien species.