Endangered species are living things whose population is so reduced that they are threatened with extinction. Thousands of species are included in this category. The International Union for the Conservation of nature and Natural Resources publishes a list of threatened mammals, birds, reptiles, amphibians, and (many people do not consider them) plants.
CAUSES OF EXTINCTION
Millions of years before humans, extinction of living things was linked to geological and climate, the effects of which were translated into major alternation of the environment.
Environmental change is still the primary cause of the extinction of animals, but now the changes are greatly accelerated by humans activity. Clearing land for farms and towns, lumbering, mining, building dams, and draining wetlands all alter the environments so extensively that ecosystems may be completely destroyed. With a burgeoning human population requiring food, shelter, and clothing and constantly demanding more energy-using devices, the temperation to exploit land for human use without regard for consequences is great. Frequently, several forms of environmental change are responsible for the disappearance of species.
For example, as tropical forests are cut down, primates have progressively smaller feeding and living spaces. They also become more accessible to hunters, who kill monkeys for food and trap many primates for sale as pets, research animals, and zoo specimens. Some animal species may move into human communities when their own are destroyed. Extermination of marauding monkeys, roaming tigers, or foraging deer is easy to justify by people whose livelihood is threatened.
Pollution is another form of environments change. Forty species of birds in the United States, including peregrine hawk, bald eagle, pelicans, and roseate terns, lay thin-shelled as a result of ingesting degradation products of and some other chlorination hydrocarbon insecticides that make their way into the food chain. Species of salamanders in New England are dying out because the ponds in which they breed and the moist soil in which they must live are watered by acid rain (water that combines with pollutants in the air to form acid, sulfuric acid, and other corrosive compounds. Industrial waste dumped in the Mediterranean have so depleted the oxygen supply that some species of bacteria that decompose sewage have been wiped out and the nutrient cycles disturbed. Even the ocean environment has been altered by dumping.
Many species have been exterminated or endangered as a result of humans killing the individuals for food. The Hawaiian state bird, the none (a type of goose), is almost as easy to catch a the legendary do do and nearly met the same fate. The 22 finds of clams and 30 kinds of fish imperiled in the United States are probably all endangered by varying combinations of naturally changing environments, pollution, and over-harvesting. Whale species are on the endangered list. Whaling is often justified as supplying a source of protein for protein-poor populations. Actually, whales supply only 1% of the protein needs of any countries, such as Japan, that is actively engaged in whaling.
In the soviet Union, whaling meat is used to feed animals that are raised for their pelts, such as sable and mink. Thus, the wearer of a ranch-raised Russian sable coat may have indirectly contributed to the ultimate disappearance of the great whales. Many species have been hunted to the point of extinction for their fur, hides or feathers. These include the big cats, alligators, kimonos, quetzel birds, eastern gray kangaroos, egrets, and bids of paradise.
Many people and groups have taken measure to stop the killing of endangered species. Whether the species were killed deliberately, or if by accident (in a oil pill) these groups are trying to stop the killing. In conclusion, I just want every one to know that endagered species can be as big as a blue whale or as small as a tiny little ant.