Extinction

Eventual extinction awaits all species of plants and animals, but the rate at which extinctions are taking place globally has been greatly accelerated by habitat destruction, pollution, global climate change, and over-harvesting to 1,000–10,000 times the normal background rate, equaling or exceeding rates of extinction during great mass extinctions of Earth's geological history. The present mass extinction is unique in that it is being caused by a single species—ours—rather than by natural events; furthermore, biologists agree that the effects may be so profound as to threaten the human species itself.

Many countries, including the United States, have passing laws to protect species that are threatened or in danger of extinction, preserving some wild areas from exploitation and some individual species from hunting and harassment. Furthermore, several private groups, such as the Nature Conservancy, seek to purchase or obtain easements on large areas of land in order to protect the life they harbor. In the case of species whose numbers have been reduced to a very low level, the role of the zoological park (or "zoo") has changed from one of simple exhibition to a more activist, wildlife-conservation stand.

Despite conservation efforts, however, the outlook is decidedly bleak. According to a 1998 poll commissioned by New York Museum of Natural History, 70–of all biologists agree with the statement that one fifth of all living species are likely to become extinct within the next 30 years. According to a statement from the World Conservation Union issued in 2000, over 11,000 species of plants and animals are already close to extinction—and the pace is accelerating. Since only 1.75 million species out of an estimated 14 million have been documented by biologists, even these numbers may understate the magnitude of the developing disaster. Although the Earth has restocked its species diversity after previous mass extinctions, this process invariably takes many millions of years.