An Endangered species is a species which has been categorized by the International Union for Conservation of Nature (IUCN) Red List as likely to become extinct. IUCN has 3 main classification categories: Extinct, Threatened and Lower Risk. Each of these main categories is subdivided into other smaller categories. Extinct: Extinct and Extinct in the Wild (which means there are only a few more living exemplars but all in special reservations); Threatened: Critically Endangered, Endangered and Vulnerable; Lower Risk: Near Threatened, Conservation Dependent and Least Concern.
The conservation status of a species indicates the likelihood that it will become extinct. Many factors are considered when assessing the conservation status of a species; e.g., such statistics as the number remaining, the overall increase or decrease in the population over time, breeding success rates, or known threats. Many nations have laws that protect conservation-reliant species: for example, forbidding hunting, restricting land development or creating preserves. Population numbers, trends and species' conservation status can be found in the lists of organisms by population.
Around the world hundreds of thousands of species are lost to extinction, many of them only discovered as remains, after they are gone. Thus, not only biological variability, but also genetic diversity, and perhaps sources of livelihood for future generations are lost. An endangered species is a species that may become extinct in the near future. Throughout history, millions of species have disappeared due to natural processes. In the past 300 years, however, humans have increased the rate of extinction.
However it is also humans which came up with conservation plans such as: Captive breeding (the process of breeding rare or endangered species in human controlled environments with restricted settings, such as wildlife preserves, zoos and other conservation facilities. Captive breeding is meant to save species from extinction and so stabilize the population of the species that it will not disappear. However, captive breeding techniques are usually difficult to implement for such highly mobile species as some migratory birds (e.g. cranes) and fishes (e.g. hilsa). Additionally, if the captive breeding population is too small, then inbreeding may occur due to a reduced gene pool and reduce immunity.) or Private Farming (Whereas poaching substantially reduces endangered animal populations, legal, for-profit, private farming does the opposite. It has substantially increased the populations of the southern black rhinoceros and southern white rhinoceros.)
I know that in our cases, there is not much that we can do except to donate money to wildlife preserving NGO (Non-governmental organizations), but it is always good to have a small knowledge of what is happening around us.