Habitat

Habitat is the environment in which natural or human species live. In all cases, a habitat is an area where an individual or population exists or can exist. The Joshua Tree, for example, can only be found in its natural habitat, which is the Mohave Desert. Water lilies can only be found in aqueous conditions, while cacti can only be found in desert conditions. Certain types of fish reside only in the ocean's abyss while longhorn sheep live on mountains.

A habitat can consist of a single individual living alone on an island, such as the fictional character Robinson Crusoe, as well as the individual members of a species in an area. Habitats can cover wide or small areas.

A microhabitat can be viewed as the immediate surroundings in which a plant or animal lives. A goldfish in a fishbowl dwells in a microhabitat. If it lived in an artificial pond, its habitat would be the area in the pond where it can swim. The microhabitat for a plant in a home aquarium is the immediate place where the planted is located.

Scientists usually use the term habitat in a gen t eral sense to mean the ecology of an area where the species exists. The habitat shared by many species is usually termed a biotope. A biome includes all of the flora and fauna living in the habitat of a certain geographic area.

The destruction of habitat is a grave danger to many species. It may well be the leading cause of species extinction. This is especially the case for species that are dependent on unique ecological niches. For example, the ivory-billed woodpecker resided only in fully matured forests. However, the destruction of most of its habitat probably caused its extinction, unless reported sightings of ivory-billed woodpeckers around 2004 turn out to be true.

Ecological niches are descriptions of the role that a species plays in an environment. The way that a species gets its food, that is, “earns its living,” can be of significance to other species. Some species such as panda occupy a narrow niche as do koala bears, which live entirely on eucalyptus leaves. Pigs, in contrast, are generalists and feed on almost anything.

Habitats can be destroyed by natural or human causes. Volcanoes can cover wide areas burying all living things under a layer of ash and lava. If a unique species has developed a special niche in the area of a dormant volcano that returns to life, it can be destroyed by geological developments.

Climatic changes have also changed the habitats of many species in the geologic ages of the earth's biography. The Sahara Desert was a grassy savannah with [Page 842]teeming wildlife 5,000–10,000 years ago. Numerous species that it supported lost their habitats because of the climatic changes that overtook the Sahara.

Habitats for some species can be greatly expanded as well as destroyed by natural or human activity. Geologic or meteorological forces can cause massive changes in the ecology of wide areas in a relatively short time. However, geological and climatic forces can also cause enormous changes in the habitat conditions. The great Sahara desert was verdant until a few thousand years ago. Climatic changes have made it into a desert without any apparent human intervention.

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