Write a short note on ENVIRONMENT-Endangered Animals
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Answer:
An endangered species is a group of organisms which is at risk of becoming extinct for one or more of three reasons: destruction or interruption of environment, in other words habitat loss; an alteration in the ecological balance resulting in an increase in predators; too few remaining members for sustainable breeding.
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Answer:
An endangered species is a group of organisms which is at risk of becoming extinct for one or more of three reasons:
destruction or interruption of environment, in other words habitat loss;
an alteration in the ecological balance resulting in an increase in predators;
too few remaining members for sustainable breeding.
A study in Nature suggested the without some form of radical change 25% of the world's land animals will become extinct within the next 50 years.
When considering the reasons why so many species are becoming endangered it is important to realise that this is very closely linked to the need to conserve the biodiversity of the planet.
Habitat loss is by far the most widespread cause of species endangerment. Usually this is due to some form of human activity. Forests are cut down to create more land for agriculture or building and coastal marshlands are drained for the same reason. Agricultural activity such as removal of hedgerows and pesticide spraying have removed both habitat and food supply for many species.
It was only after a noticeable decline in numbers of the bald eagle and the peregrine falcon that the use of DDT and other persistent pesticides began to be questioned. When the ecosystem of a species is not maintained, such as the removal of a food supply, the species is forced to adapt to new surroundings or perish.
Pollution is a major disrupter and destroyer of ecosystems and this was graphically illustrated following the April 2010 Deepwater Horizon oil disaster in the Gulf of Mexico. This devastated many marine ecosystems and caused the death of countless seabirds and marine creatures.
Overexploitation, such as deepwater trawling has put a number of species of fish at serious risk. This can also have a knock-on effect of removing the food supply of other marine creatures, putting them at risk as a consequence.
Climate change can alter the delicate balance of an ecosystem. Relatively minor changes in temperature can allow some species to thrive, while others perish. More dramatic climate changes can lead to the melting of ice caps and glaciers, with the consequent disruption to the local ecosystems. On a worldwide basis, the resulting rise in sea levels can disrupt the ecosystems of many species, including humans.
Habitat loss can also occur when alien species are introduced into ecosystems, either by chance or by design. In 1918 a ship ran aground on a Pacific island. While the ship was being repaired a number of Black Rats escaped and set up a thriving colony on the island. Within a short time they had wiped out several of the island's native birds and other fauna. The islanders introduced masked owls in an effort to control the rats, but this simple led to the loss of many of the remaining sea birds.
As habitat loss combines with other ecological disruptions, many species find it increasingly difficult to breed. This leads to a gradual decline in numbers until the point is reached where the species is no longer sustainable.
The International Union for Conservation of Nature (IUCN) maintains a Red List of Threatened Species. This is the most comprehensive inventory of the global status of plant and animal species. IUCN calculates that around 40% of the world's organisms are endangered.
The IUCN has a classification system to enable criteria to be set with respect to rate of decline, population size, area of geographic distribution and the degree of population and distribution fragmentation.