In general, a habitat is any place where a particular animal or plant species lives. It can also be thought of as the environment or surroundings of a species. Examples of a habitat include a lake, a stream, or even a drop of water.

         All habitats on Earth is part of the biosphere. Since the Earth is always changing, habitats are continually evolving as well. Over billions of years, the natural habitats have supported a great variety of species. Another major factor affecting habitats are humans. Things we do can increase or decrease the number of certain species.

         Descriptions of environment such as temperature and rainfall are used to group habitats together. Habitats of similar climate and vegetation are called biomes. In different parts of the world, the same biome may contain different species, but similar life-forms can always be identified. For example, the tree is the dominant form of the rain forest, no matter where the rain forest is located.